PC78MR-6_SEBM030601
Short Description
manual oficina...
Description
SEBM030601
MACHINE MODEL
SERIAL NUMBER
PC78MR-6
1001 and up
• This shop manual may contain attachments and optional equipment that are not available in your area. Please consult your local Komatsu distributor for those items you may require. Materials and specifications are subject to change without notice. • PC78MR-6 mounts the S4D95LE-3-A engine. For details of the engine, see the 95-3 Series Engine Shop Manual.
© 2003 All Rights Reserved Printed in Japan 12-03(02)
00-1 (1)
CONTENTS No. of page
01
GENERAL ................................................................................................................01-1
10
STRUCTURE AND FUNCTION, MAINTENANCE STANDARD......................................................................10-1
20
TESTING AND ADJUSTING .......................................................................20-1
30
DISASSEMBLY AND ASSEMBLY ..........................................................30-1
90
OTHERS ....................................................................................................................90-1
00-2
PC78MR-6
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00-2-3 (1)
SAFETY
SAFETY NOTICE
SAFETY SAFETY NOTICE IMPORTANT SAFETY NOTICE Proper service and repair is extremely important for safe machine operation. The service and repair techniques recommended by Komatsu and described in this manual are both effective and safe. Some of these techniques require the use of tools specially designed by Komatsu for the specific purpose.
¤
To prevent injury to workers, the symbol is used to mark safety precautions in this manual. The cautions accompanying these symbols should always be followed carefully. If any dangerous situation arises or may possibly arise, first consider safety, and take the necessary actions to deal with the situation.
GENERAL PRECAUTIONS Mistakes in operation are extremely dangerous. Read the Operation and Maintenance Manual carefully BEFORE operating the machine. 1. Before carrying out any greasing or repairs, read all the precautions given on the decals which are fixed to the machine. 2. When carrying out any operation, always wear safety shoes and helmet. Do not wear loose work clothes, or clothes with buttons missing. • •
Always wear safety glasses when hitting parts with a hammer. Always wear safety glasses when grinding parts with a grinder, etc.
3. If welding repairs are needed, always have a trained, experienced welder carry out the work. When carrying out welding work, always wear welding gloves, apron, hand shield, cap and other clothes suited for welding work. 4. When carrying out any operation with two or more workers, always agree on the operating procedure before starting. Always inform your fellow workers before starting any step of the operation. Before starting work, hang UNDER REPAIR signs on the controls in the operator's compartment. 5. Keep all tools in good condition and learn the correct way to use them.
6. Decide a place in the repair workshop to keep tools and removed parts. Always keep the tools and parts in their correct places. Always keep the work area clean and make sure that there is no dirt or oil on the floor. Smoke only in the areas provided for smoking. Never smoke while working. PREPARATIONS FOR WORK 7. Before adding oil or making any repairs, park the machine on hard, level ground, and block the wheels or tracks to prevent the machine from moving. 8. Before starting work, lower blade, ripper, bucket or any other work equipment to the ground. If this is not possible, insert the safety pin or use blocks to prevent the work equipment from falling. In addition, be sure to lock all the control levers and hang warning signs on them. 9. When disassembling or assembling, support the machine with blocks, jacks or stands before starting work. 10.Remove all mud and oil from the steps or other places used to get on and off the machine. Always use the handrails, ladders or steps when getting on or off the machine. Never jump on or off the machine. If it is impossible to use the handrails, ladders or steps, use a stand to provide safe footing.
00-3
SAFETY
PRECAUTIONS DURING WORK 11. When removing the oil filler cap, drain plug or hydraulic pressure measuring plugs, loosen them slowly to prevent the oil from spurting out. Before disconnecting or removing components of the oil, water or air circuits, first remove the pressure completely from the circuit. 12.The water and oil in the circuits are hot when the engine is stopped, so be careful not to get burned. Wait for the oil and water to cool before carrying out any work on the oil or water circuits. 13.Before starting work, remove the leads from the battery. Always remove the lead from the negative (–) terminal first. 14.When raising heavy components, use a hoist or crane. Check that the wire rope, chains and hooks are free from damage. Always use lifting equipment which has ample capacity. Install the lifting equipment at the correct places. Use a hoist or crane and operate slowly to prevent the component from hitting any other part. Do not work with any part still raised by the hoist or crane. 15.When removing covers which are under internal pressure or under pressure from a spring, always leave two bolts in position on opposite sides. Slowly release the pressure, then slowly loosen the bolts to remove. 16.When removing components, be careful not to break or damage the wiring. Damaged wiring may cause electrical fires. 17.When removing piping, stop the fuel or oil from spilling out. If any fuel or oil drips onto the floor, wipe it up immediately. Fuel or oil on the floor can cause you to slip, or can even start fires. 18.As a general rule, do not use gasoline to wash parts. In particular, use only the minimum of gasoline when washing electrical parts.
00-4
SAFETY NOTICE
19.Be sure to assemble all parts again in their original places. Replace any damaged parts with new parts. • When installing hoses and wires, be sure that they will not be damaged by contact with other parts when the machine is being operated. 20.When installing high pressure hoses, make sure that they are not twisted. Damaged tubes are dangerous, so be extremely careful when installing tubes for high pressure circuits. Also, check that connecting parts are correctly installed. 21.When assembling or installing parts, always use the specified tightening torques. When installing protective parts such as guards, or parts which vibrate violently or rotate at high speed, be particularly careful to check that they are installed correctly. 22.When aligning two holes, never insert your fingers or hand. Be careful not to get your fingers caught in a hole. 23.When measuring hydraulic pressure, check that the measuring tool is correctly assembled before taking any measurements. 24.Take care when removing or installing the tracks of track-type machines. When removing the track, the track separates suddenly, so never let anyone stand at either end of the track.
FOREWORD
GENERAL
FOREWORD GENERAL This shop manual has been prepared as an aid to improve the quality of repairs by giving the serviceman an accurate understanding of the product and by showing him the correct way to perform repairs and make judgements. Make sure you understand the contents of this manual and use it to full effect at every opportunity.
This shop manual mainly contains the necessary technical information for operations performed in a service workshop. For ease of understanding, the manual is divided into the following chapters; these chapters are further divided into the each main group of components.
STRUCTURE AND FUNCTION This section explains the structure and function of each component. It serves not only to give an understanding of the structure, but also serves as reference material for troubleshooting. In addition, this section may contain hydraulic circuit diagrams, electric circuit diagrams, and maintenance standards. TESTING AND ADJUSTING This section explains checks to be made before and after performing repairs, as well as adjustments to be made at completion of the checks and repairs. Troubleshooting charts correlating "Problems" with "Causes" are also included in this section. DISASSEMBLY AND ASSEMBLY This section explains the procedures for removing, installing, disassembling and assembling each component, as well as precautions for them. MAINTENANCE STANDARD This section gives the judgment standards for inspection of disassembled parts. The contents of this section may be described in STRUCTURE AND FUNCTION. OTHERS This section mainly gives hydraulic circuit diagrams and electric circuit diagrams. In addition, this section may give the specifications of attachments and options together.
NOTICE The specifications contained in this shop manual are subject to change at any time and without any advance notice. Use the specifications given in the book with the latest date.
00-5
FOREWORD
HOW TO READ THE SHOP MANUAL
HOW TO READ THE SHOP MANUAL
REVISED EDITION MARK
VOLUMES Shop manuals are issued as a guide to carrying out repairs. They are divided as follows:
W h en a m an u a l is r e vis ed , a n e d itio n ma rk ( ....) is recorded on the bottom of the pages.
Chassis volume: Issued for every machine model Engine volume: Issued for each engine series Each issued as one Electrical volume: Attachments volume: · volume to cover all models
REVISIONS
}
These various volumes are designed to avoid duplicating the same information. Therefore, to deal with all repairs for any model , it is necessary that chassis, engine, electrical and attachment volumes be available. DISTRIBUTION AND UPDATING Any additions, amendments or other changes will be sent to KOMATSU distributors. Get the most up-todate information before you start any work.
FILING METHOD 1. See the page number on the bottom of the page. File the pages in correct order. 2. Following examples show how to read the page number. Example 1 (Chassis volume): 10 - 3 Item number (10. Structure and Function) Consecutive page number for each item. Example 2 (Engine volume): 12 - 5 Unit number (1. Engine) Item number (2. Testing and Adjusting) Consecutive page number for each item. 3. Additional pages: Additional pages are indicated by a hyphen (-) and number after the page number. File as in the example. Example: 12-203 10-4 12-203-1 10-4-1 Added pages 12-203-2 10-4-2 12-204 10-5
00-6
123
Revised pages are shown in the LIST OF REVISED PAGES next to the CONTENTS page.
SYMBOLS So that the shop manual can be of ample practical use, important safety and quality portions are marked with the following symbols.
Symbol
Item
Remarks
¤
Safety
Special safety precautions are necessary when performing the work.
Caution
Special technical precautions or other precautions for preserving standards are necessary when performing the work.
Weight
Weight of parts of systems. Caution necessary when selecting hoisting wire, or when working posture is important, etc.
Tightening torque
Places that require special attention for the tightening torque during assembly.
Coat
Places to be coated with adhesives and lubricants, etc.
Oil, water
Places where oil, water or fuel must be added, and the capacity.
Drain
Places where oil or water m u s t b e d r a i n e d , a nd quantity to be drained.
s
4 3 2 5 6
FOREWORD
HOISTING INSTRUCTIONS
HOISTING INSTRUCTIONS HOISTING
¤ •
Heavy parts (25 kg or more) must be lifted with a hoist, etc. In the DISASSEMBLY AND ASSEMBLY section, every part weighing 25 kg or more is indicated clearly with the symbol
4
If a part cannot be smoothly removed from the machine by hoisting, the following checks should be made: 1) Check for removal of all bolts fastening the part to the relative parts. 2) Check for existence of another part causing interference with the part to be removed.
WIRE ROPES 1) Use adequate ropes depending on the weight of parts to be hoisted, referring to the table below: Wire ropes (Standard "Z" or "S" twist ropes without galvanizing) Rope diameter
★
Allowable load
mm
kN
tons
10 11.5 12.5 14 16 18 20 22.4 30 40 50 60
9.8 13.7 15.7 21.6 27.5 35.3 43.1 54.9 98.1 176.5 274.6 392.2
1.0 1.4 1.6 2.2 2.8 3.6 4.4 5.6 10.0 18.0 28.0 40.0
Slinging near the edge of the hook may cause the rope to slip off the hook during hoisting, and a serious accident can result. Hooks have maximum strength at the middle portion.
100%
88%
79%
71%
41% SAD00479
3) Do not sling a heavy load with one rope alone, but sling with two or more ropes symmetrically wound onto the load. Slinging with one rope may cause turning of the load during hoisting, untwisting of the rope, or slipping of the rope from its original winding position on the load, which can result in a dangerous accident.
¤
4) Do not sling a heavy load with ropes forming a wide hanging angle from the hook. When hoisting a load with two or more ropes, the force subjected to each rope will increase with the hanging angles. The table below shows the variation of allowable load kN {kg} when hoisting is made with two ropes, each of which is allowed to sling up to 9.8 kN {1000 kg} vertically, at various hanging angles. When two ropes sling a load vertically, up to 19.6 kN {2000 kg} of total weight can be suspended. This weight becomes 9.8 kN {1000 kg} when two ropes make a 120° hanging angle. On the other hand, two ropes are subjected to an excessive force as large as 39.2 kN {4000 kg} if they sling a 19.6 kN {2000 kg} load at a lifting angle of 150°.
The allowable load value is estimated to be onesixth or one-seventh of the breaking strength of the rope used.
2) Sling wire ropes from the middle portion of the hook.
00-7
FOREWORD
METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER
METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER
¤ ¤
Before carrying out the following work, release the residual pressure from the hydraulic tank. For details, see TESTING AND ADJUSTING, Releasing residual pressure from hydraulic tank. Even if the residual pressure is released from the hydraulic tank, some hydraulic oil flows out when the hose is disconnected. Accordingly, prepare an oil receiving container.
Disconnection 1) Release the residual pressure from the hydraulic tan k. Fo r d e tails , se e TES TIN G AN D ADJUSTING, Releasing residual pressure from hydraulic tank. 2) Hold adapter (1) and push hose joint (2) into mating adapter (3). (See Fig. 1) ★ The adapter can be pushed in about 3.5 mm. ★ Do not hold rubber cap portion (4). 3) After hose joint (2) is pushed into adapter (3), press rubber cap portion (4) against (3) until it clicks. (See Fig. 2) 4) Hold hose adapter (1) or hose (5) and pull it out. (See Fig. 3) ★ Since some hydraulic oil flows out, prepare an oil receiving container. Connection 1) Hold hose adapter (1) or hose (5) and insert it in mating adapter (3), aligning them with each other. (See Fig. 4) ★ Do not hold rubber cap portion (4). 2) After inserting the hose in the mating adapter perfectly, pull it back to check its connecting condition. (See Fig. 5) ★ When the hose is pulled back, the rubber cap portion moves toward the hose about 3.5 mm. This does not indicate abnormality, however.
00-8
Type 1
FOREWORD
METHOD OF DISASSEMBLING, CONNECTING PUSH-PULL TYPE COUPLER
Type 3
1) Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end.
1) Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end.
2) Hold in the condition in Step 1), and turn lever (4) to the right (clockwise).
2) Hold in the condition in Step 1), and push until cover (3) contacts contact surface a of the hexagonal portion at the male end.
3) Hold in the condition in Steps 1) and 2), and pull out whole body (2) to disconnect it.
3) Hold in the condition in Steps 1) and 2), and pull out whole body (2) to disconnect it.
•
•
Disassembly
Type 2
Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end to connect it.
Connection
Hold the mouthpiece of the tightening portion and push body (2) in straight until sliding prevention ring (1) contacts contact surface a of the hexagonal portion at the male end to connect it.
00-9
FOREWORD
COATING MATERIALS
COATING MATERIALS ★ ★
The recommended coating materials such as adhesives, gasket sealants and greases used for disassembly and assembly are listed below. For coating materials not listed below, use the equivalent of products shown in this list.
Category
Komatsu code
Part No.
Q'ty
Container
LT-1A
790-129-9030
150 g
Tube
LT-1B
790-129-9050
20 g (2 pcs.)
Polyethylene container
LT-2
09940-00030
50 g
Polyethylene container
LT-3
790-129-9060 (Set of adhesive and hardening agent)
Adhesive: 1 kg Hardenin g agent: 500 g
Can
LT-4
790-129-9040
250 g
Polyethylene container
Holtz MH 705
790-126-9120
75 g
Tube
Three bond 1735
790-129-9140
50 g
Polyethylene container
2g
Polyethylene container
Adhesives
Aron-alpha 201
790-129-9130
Loctite 648-50
79A-129-9110
50 cc
Polyethylene container
LG-1
790-129-9010
200 g
Tube
LG-5
790-129-9070
1 kg
Can
Main applications, featuresr •
Used to prevent rubber gaskets, rubber cushions, and cock plug from coming out.
•
Used in places requiring an immediately effective, strong adhesive. Used for plastics (except polyethylene, polyprophylene, tetrafluoroet hl ene and vi nyl chl oride), rubber, metal and non-metal.
• •
Features: Resistance to heat and chemicals Used for anti-loosening and sealant purpose for bolts and plugs.
•
Used as adhesive or sealant for metal, glass and plastic.
•
Used as sealant for machined holes.
•
Used as heat-resisting sealant for repairing engine.
• • •
Quick hardening type adhesive Cure time: within 5 sec. to 3 min. Used mainly for adhesion of metals, rubbers, plastics and woods.
• •
Quick hardening type adhesive Quick cure type (max. strength after 30 minutes) Used mainly for adhesion of rubbers, plastics and metals.
• • •
Resistance to heat, chemicals Used at joint portions subject to high temperatures.
•
Used as adhesive or sealant for gaskets and packing of power train case, etc.
•
Used as sealant for various threads, pipe joints, flanges. Used as sealant for tapered plugs, elbows, nipples of hydraulic piping.
•
Gasket sealant • LG-6
790-129-9020
200 g
Tube
• •
00-10
Features: Silicon based, resistance to heat, cold Used as sealant for flange surface, tread. mab Used as sealant for oil pan, final drive case, etc.
FOREWORD
Category
COATING MATERIALS
Komatsu code
Part No.
Q'ty
Container
Main applications, featuresr •
LG-7
790-129-9070
1g
Tube
Three bond 1211
790-129-9090
100 g
Tube
LM-G
09940-00051
60 g
Can
•
Adhesives
Molybdenum disulphide lubricant
LM-P
09940-00040
200 g
•
Used as heat-resisting sealant for repairing engine.
•
Used as lubricant for sliding portion (to prevent from squeaking).
•
Used to prevent seizure or scuffling of the thread when press fitting or shrink fitting. Used as lubricant for linkage, bearings, etc.
Tube •
G2-LI
SYG2-400LI SYG2-350LI SYG2-400LI-A SYG2-160LI SYGA-160CNLI
G2-CA
SYG2-400CA SYG2-350CA SYG2-400CA-A SYG2-160CA SYGA-160CNCA
Various
Various
Molybdenum disulphide lubricant
SYG2-400M
400 g (10 per case)
Belows type
Grease
Various
Ftures: Silicon based, quick hardening type Used as sealant for flywheel housing, intake manifold, oil an, thermostat housing, etc.
•
General purpose type
•
Used for normal temperature, light load bearing at places in contact with water or steam.
•
Used for places with heavy load
Various
00-11
FOREWORD
STANDARD TIGHTENING TORQUE
STANDARD TIGHTENING TORQUE STANDARD TIGHTENING TORQUE TABLE (WHEN USING TORQUE WRENCH) ★ In the case of metric nuts and bolts for which there is no special instruction, tighten to the torque given in the table below. Thread diameter of bolt
Width across flats
mm
mm
6 8 10 12 14
10 13 17 19 22
16 18 20 22 24
24 27 30 32 36
27 30 33 36 39
41 46 50 55 60
Thread diameter of bolt
Width across flats
mm
mm
Nm
6 8 10 12
10 13 14 27
7.85 1.95 18.6 4.9 40.2 5.9 82.35 7.85
Nm
kgm
0 0.15 0 0.3 0 0.7 01 02 28.5 0 3 39 0 4 56 0 6 76 0 8.5 94.5 0 10.5 135 0 15 175 0 20 225 0 25 280 0 30 335 0 35
0 1.4 03 07 0 10 0 19 279 0 30 382 0 39 549 0 59 745 0 83 927 0 103 1320 0 140 1720 0 190 2210 0 240 2750 0 290 3290 0 340
1.35 3.2 6.7 11.5 18
13.2 31 66 113 177
kgm
0 0 0 0
0.8 1.9 4.1 8.4
0 0.2 0 0.5 0 0.6 0 0.8
Sealing surface
TABLE OF TIGHTENING TORQUES FOR FLARED NUTS ★ In the case of flared nuts for which there is no special instruction, tighten to the torque given in the table below.
SAD00483
Thread diameter
Width across flat
mm
mm
Nm
kgm
14 18 22 24 30 33 36 42
19 24 27 32 36 41 46 55
24.5 4.9 49 19.6 78.5 19.6 137.3 29.4 176.5 29.4 196.1 49 245.2 49 294.2 49
2.5 0.5 5 2 8 2 14 3 18 3 20 5 25 5 30 5
00-12
Tightening torque
0 0 0 0 0 0 0 0
0 0 0 0 0 0 0 0
FOREWORD
STANDARD TIGHTENING TORQUE
TABLE OF TIGHTENING TORQUES FOR SPLIT FLANGE BOLTS ★ In the case of split flange bolts for which there is no special instruction, tighten to the torque given in the table below.
Thread diameter
Width across flat
Tightening torque
mm
mm
Nm
kgm
10 12 16
14 17 22
65.7 6.8 112 9.8 279 29
0 0 0
6.7 0.7 11.5 1 28.5 3
0
0 0
TABLE OF TIGHTENING TORQUES FOR O-RING BOSS PIPING JOINTS ★ Unless there are special instructions, tighten the O-ring boss piping joints to the torque below.
Thread diameter
Width across flat
Tightening torque
mm
mm
Nm
14 20 24 33 42
Varies depending on type of connector.
34.3 4.9 93.1 9.8 142.1 19.6 421.4 58.8 877.1 132.3
Norminal No.
02 03, 04 05, 06 10, 12 14
kgm
0 0 0 0 0
0 0.5 01 02 06 0 13.5
3.5 9.5 14.5 43 89.5
TABLE OF TIGHTENING TORQUES FOR O-RING BOSS PLUGS ★ Unless there are special instructions, tighten the O-ring boss plugs to the torque below.
Thread diameter
Width across flat
Tightening torque
mm
mm
Nm
kgm
08 10 12 14 16 18 20 24 30 33 36 42 52
14 17 19 22 24 27 30 32 32 n 36 n n
7.35 1.47 11.27 1.47 17.64 1.96 22.54 1.96 29.4 4.9 39.2 4.9 49 4.9 68.6 9.8 107.8 14.7 127.4 19.6 151.9 24.5 210.7 29.4 323.4 44.1
0 0 0 0 0 0 0 0 0 0 0 0 0
0.75 0.15 1.15 0.15 1.8 0.2 2.3 0.2 3 0.5 4 0.5 5 0.5 7 1 11 1.5 13 2 15.5 2.5 21.5 3 33 4.5
Norminal No.
08 10 12 14 16 18 20 24 30 33 36 42 52
0 0 0 0 0 0 0 0 0 0 0 0 0
00-13
FOREWORD
STANDARD TIGHTENING TORQUE
TIGHTENING TORQUE FOR 102 ENGINE SERIES 1) BOLT AND NUTS Use these torques for bolts and nuts (unit: mm) of Cummins Engine. Thread diameter
Tightening torque
mm
Nm
6 8 10 12
10 2 24 4 43 6 77 12
kgm
0 0 0 0
1.02 2.45 4.38 7.85
0 0.20 0 0.41 0 0.61 0 1.22
2) EYE JOINTS Use these torques for eye joints (unit: mm) of Cummins Engine. Thread diameter
Tightening torque
mm
Nm
6 8 10 12 14
8 2 10 2 12 2 24 4 36 5
kgm
0 0 0 0 0
0.81 1.02 1.22 2.45 3.67
0 0.20 0 0.20 0 0.20 0 0.41 0 0.51
3) TAPERED SCREWS Use these torques for tapered screws (unit: inch) of Cummins Engine. Thread diameter
Tightening torque
inch
Nm
1 / 16 1/8 1/4 3/8 1/2 3/4 1
3 1 8 2 12 2 15 2 24 4 36 5 60 9
kgm
0 0 0 0 0 0 0
0.31 0.81 1.22 1.53 2.45 3.67 6.12
0 0.10 0 0.20 0 0.20 0 0.41 0 0.41 0 0.51 0 0.92
TIGHTENING TORQUE TABLE FOR HOSES (TAPER SEAL TYPE AND FACE SEAL TYPE) ★ Tighten the hoses (taper seal type and face seal type) to the following torque, unless otherwise specified. ★ Apply the following torque when the threads are coated (wet) with engine oil. Tightening torque (Nm {kgm}) Nominal size Width across of hose flats
Taper seal type
Face seal type
Nominal thread Thread size size - Threads per Root diameter (mm) (mm) (Reference) inch, Thread series
Range
Target
19
35 - 63 {3.5 - 6.5}
44 {4.5}
14
9 – - 18UNF 16
14.3
22
54 - 93 {5.5 - 9.5}
74 {4.5}
–
11 – - 16UN 16
17.5
24
59 - 98 {6.0 - 10.0}
78 {8.0}
18
–
–
04
27
84 - 132 {8.5 - 13.5}
103 {10.5}
22
13 – - 16UN 16
20.7
05
32
128 - 186 {13.0 - 19.0}
157 {16.0}
24
1 - 14UNS
25.4
06
36
177 - 245 {18.0 - 25.0}
216 {22.0}
30
3 1 – - 12UNF 16
30.3
(10)
41
177 - 245 {18.0 - 25.0}
216 {22.0}
33
–
–
(12)
46
197 - 294 {20.0 - 30.0}
245 {25.0}
36
–
–
(14)
55
246 - 343 {25.0 - 35.0}
294 {30.0}
42
–
–
02
03
00-14
FOREWORD
ELECTRIC WIRE CODE
ELECTRIC WIRE CODE In the wiring diagrams, various colors and symbols are employed to indicate the thickness of wires. This wire code table will help you understand WIRING DIAGRAMS. Example: 5WB indicates a cable having a nominal number 5 and white coating with black stripe.
CLASSIFICATION BY THICKNESS
Copper wire Cable O.D. (mm)
Current rating (A)
Applicable circuit
0.88
2.4
12
Starting, lighting, signal etc.
0.32
2.09
3.1
20
Lighting, signal etc.
65
0.32
5.23
4.6
37
Charging and signal
15
84
0.45
13.36
7.0
59
Starting (Glow plug)
40
85
0.80
42.73
11.4
135
Starting
60
127
0.80
63.84
13.6
178
Starting
100
217
0.80
109.1
17.6
230
Starting
Norminal number
Number of strands
Dia. of strands (mm2)
Cross section (mm 2)
0.85
11
0.32
2
26
5
CLASSIFICATION BY COLOR AND CODE Circuits Priority Classification
1
Primary
Charging
Ground
Starting
Lighting
Instrument
Signal
Other
Code
W
B
B
R
Y
G
L
Color
White
Black
Black
Red
Yellow
Green
Blue
Code
WR
BW
RW
YR
GW
LW
2 Color White & Red Code
WB
3 Color White & Black Code 4
Auxiliary
WL
Color White & Blue Code
WG
5 Color White & Green Code 6 Color
n n
n n n n n n n n n n
White & Black Red & White Rellow & Red Green & White Blue & White BY
RB
YB
GR
LR
Black & Yellow Red & Black Yellow & Black Green & Red Blue & Yellow BR
RY
Black & Red Red & Yellow
n n n n
RG
YG
GY
LY
Yellow & Green
Green & Yellow
Blue & Yellow
YL
GB
LB
Red & Green Yellow & Blue Green & Black Blue & Black RL
YW
GL
Red & Blue Yellow & White Green & Blue
n n 00-15
FOREWORD
CONVERSION TABLE
CONVERSION TABLE METHOD OF USING THE CONVERSION TABLE The Conversion Table in this section is provided to enable simple conversion of figures. For details of the method of using the Conversion Table, see the example given below.
EXAMPLE • Method of using the Conversion Table to convert from millimeters to inches 1. Convert 55 mm into inches. (1) Locate the number 50 in the vertical column at the left side, take this as , then draw a horizontal line from . (2) Locate the number 5 in the row across the top, take this as , then draw a perpendicular line down from . (3) Take the point where the two lines cross as . This point gives the value when converting from millimeters to inches. Therefore, 55 mm = 2.165 inches. 2. Convert 550 mm into inches. (1) The number 550 does not appear in the table, so divide by 10 (move the decimal point one place to the left) to convert it to 55 mm. (2) Carry out the same procedure as above to convert 55 mm to 2.165 inches. (3) The original value (550 mm) was divided by 10, so multiply 2.165 inches by 10 (move the decimal point one place to the right) to return to the original value. This gives 550 mm = 21.65 inches.
A B
C
C
A
B
B Millimeters to inches 1 mm = 0.03937 in
A
00-16
0
1
2
3
4
5
6
7
8
9
0 10 20 30 40
0 0.394 0.787 1.181 1.575
0.039 0.433 0.827 1.220 1.614
0.079 0.472 0.866 1.260 1.654
0.118 0.512 0.906 1.299 1.693
0.157 0.551 0.945 1.339 1.732
0.197 0.591 0.984 1.378 1.772
0.236 0.630 1.024 1.417 1.811
0.276 0.669 1.063 1.457 1.850
0.315 0.709 1.102 1.496 1.890
0.354 0.748 1.142 1.536 1.929
50 60 70 80 90
1.969 2.362 2.756 3.150 3.543
2.008 2.402 2.795 3.189 3.583
2.047 2.441 2.835 3.228 3.622
2.087 2.480 2.874 3.268 3.661
2.126 2.520 2.913 3.307 3.701
2.165 2.559 2.953 3.346 3.740
2.205 2.598 2.992 3.386 3.780
2.244 2.638 3.032 3.425 3.819
2.283 2.677 3.071 3.465 3.858
2.323 2.717 3.110 3.504 3.898
C
FOREWORD
CONVERSION TABLE
Millimeters to Inches 1 mm = 0.03937 in
0
1
2
3
4
5
6
7
8
9
0
0.039
0.079
0.118
0.157
0.197
0.236
0.276
0.315
0.354
10
0.394
0.433
0.472
0.512
0.551
0.591
0.630
0.669
0.709
0.748
20
0.787
0.827
0.866
0.906
0.945
0.984
1.024
1.063
1.102
1.142
30
1.181
1.220
1.260
1.299
1.339
1.378
1.417
1.457
1.496
1.536
40
1.575
1.614
1.654
1.693
1.732
1.772
1.811
1.850
1.890
1.929
50
1.969
2.008
2.047
2.087
2.126
2.165
2.205
2.244
2.283
2.323
60
2.362
2.402
2.441
2.480
2.520
2.559
2.598
2.638
2.677
2.717
70
2.756
2.795
2.835
2.874
2.913
2.953
2.992
3.032
3.071
3.110
80
3.150
3.189
3.228
3.268
3.307
3.346
3.386
3.425
3.465
3.504
90
3.543
3.583
3.622
3.661
3.701
3.740
3.780
3.819
3.858
3.898
0
Kilogram to Pound 1 kg = 2.2046 lb
0 0
0
1
2
3
4
5
6
7
8
9
2.20
4.41
6.61
8.82
11.02
13.23
15.43
17.64
19.84
10
22.05
24.25
26.46
28.66
30.86
33.07
35.27
37.48
39.68
41.89
20
44.09
46.30
48.50
50.71
51.91
55.12
57.32
59.53
61.73
63.93
30
66.14
68.34
70.55
72.75
74.96
77.16
79.37
81.57
83.78
85.98
40
88.18
90.39
92.59
94.80
97.00
99.21
101.41
103.62
105.82
108.03
50
110.23
112.44
114.64
116.85
119.05
121.25
123.46
125.66
127.87
130.07
60
132.28
134.48
136.69
138.89
141.10
143.30
145.51
147.71
149.91
152.12
70
154.32
156.53
158.73
160.94
163.14
165.35
167.55
169.76
171.96
174.17
80
176.37
178.57
180.78
182.98
185.19
187.39
189.60
191.80
194.01
196.21
90
198.42
200.62
202.83
205.03
207.24
209.44
211.64
213.85
216.05
218.26
00-17
FOREWORD
CONVERSION TABLE
Liter to U.S. Gallon 1l = 0.2642 U.S. Gal
0
1
2
3
4
5
6
7
8
9
0
0.264
0.528
0.793
1.057
1.321
1.585
1.849
2.113
2.378
10
2.642
2.906
3.170
3.434
3.698
3.963
4.227
4.491
4.755
5.019
20
5.283
5.548
5.812
6.076
6.340
6.604
6.869
7.133
7.397
7.661
30
7.925
8.189
8.454
8.718
8.982
9.246
9.510
9.774
10.039
10.303
40
10.567
10.831
11.095
11.359
11.624
11.888
12.152
12.416
12.680
12.944
50
13.209
13.473
13.737
14.001
14.265
14.529
14.795
15.058
15.322
15.586
60
15.850
16.115
16.379
16.643
16.907
17.171
17.435
17.700
17.964
18.228
70
18.492
18.756
19.020
19.285
19.549
19.813
20.077
20.341
20.605
20.870
80
21.134
21.398
21.662
21.926
22.190
22.455
22.719
22.983
23.247
23.511
90
23.775
24.040
24.304
24.568
24.832
25.096
25.361
25.625
25.889
26.153
0
Liter to U.K. Gallon 1l = 0.21997 U.K. Gal
0
1
2
3
4
5
6
7
8
9
0
0.220
0.440
0.660
0.880
1.100
1.320
1.540
1.760
1.980
10
2.200
2.420
2.640
2.860
3.080
3.300
3.520
3.740
3.950
4.179
20
4.399
4.619
4.839
5.059
5.279
5.499
5.719
5.939
6.159
6.379
30
6.599
6.819
7.039
7.259
7.479
7.969
7.919
8.139
8.359
8.579
40
8.799
9.019
9.239
9.459
9.679
9.899
10.119
10.339
10.559
10.778
50
10.998
11.281
11.438
11.658
11.878
12.098
12.318
12.528
12.758
12.978
60
13.198
13.418
13.638
13.858
14.078
14.298
14.518
14.738
14.958
15.178
70
15.398
15.618
15.838
16.058
16.278
16.498
16.718
16.938
17.158
17.378
80
17.598
17.818
18.037
18.257
18.477
18.697
18.917
19.137
19.357
19.577
90
19.797
20.017
20.237
20.457
20.677
20.897
21.117
21.337
21.557
21.777
0
00-18
FOREWORD
CONVERSION TABLE
kgm to ft. lb 1 kgm = 7.233 ft. lb
0
1
2
3
4
5
6
7
8
9
0
0
7.2
14.5
21.7
28.9
36.2
43.4
50.6
57.9
65.1
10
72.3
79.6
86.8
94.0
101.3
108.5
115.7
123.0
130.2
137.4
20
144.7
151.9
159.1
166.4
173.6
180.8
188.1
195.3
202.5
209.8
30
217.0
224.2
231.5
238.7
245.9
253.2
260.4
267.6
274.9
282.1
40
289.3
296.6
303.8
311.0
318.3
325.5
332.7
340.0
347.2
354.4
50
361.7
368.9
376.1
383.4
390.6
397.8
405.1
412.3
419.5
426.8
60
434.0
441.2
448.5
455.7
462.9
470.2
477.4
484.6
491.8
499.1
70
506.3
513.5
520.8
528.0
535.2
542.5
549.7
556.9
564.2
571.4
80
578.6
585.9
593.1
600.3
607.6
614.8
622.0
629.3
636.5
643.7
90
651.0
658.2
665.4
672.7
679.9
687.1
694.4
701.6
708.8
716.1
100
723.3
730.5
737.8
745.0
752.2
759.5
766.7
773.9
781.2
788.4
110
795.6
802.9
810.1
817.3
824.6
831.8
839.0
846.3
853.5
860.7
120
868.0
875.2
882.4
889.7
896.9
904.1
911.4
918.6
925.8
933.1
130
940.3
947.5
954.8
962.0
969.2
976.5
983.7
990.9
998.2
1005.4
140
1012.6
1019.9
1027.1
1034.3
1041.5
1048.8
1056.0
1063.2
1070.5
1077.7
150
1084.9
1092.2
1099.4
1106.6
1113.9
1121.1
1128.3
1135.6
1142.8
1150.0
160
1157.3
1164.5
1171.7
1179.0
1186.2
1193.4
1200.7
1207.9
1215.1
1222.4
170
1129.6
1236.8
1244.1
1251.3
1258.5
1265.8
1273.0
1280.1
1287.5
1294.7
180
1301.9
1309.2
1316.4
1323.6
1330.9
1338.1
1345.3
1352.6
1359.8
1367.0
190
1374.3
1381.5
1388.7
1396.0
1403.2
1410.4
1417.7
1424.9
1432.1
1439.4
00-19
FOREWORD
CONVERSION TABLE
kg/cm2 to lb/in2 1kg/cm2 = 14.2233 lb/in2
0
1
2
3
4
5
6
7
8
9
0
0
14.2
28.4
42.7
56.9
71.1
85.3
99.6
113.8
128.0
10
142.2
156.5
170.7
184.9
199.1
213.4
227.6
241.8
256.0
270.2
20
284.5
298.7
312.9
327.1
341.4
355.6
369.8
384.0
398.3
412.5
30
426.7
440.9
455.1
469.4
483.6
497.8
512.0
526.3
540.5
554.7
40
568.9
583.2
597.4
611.6
625.8
640.1
654.3
668.5
682.7
696.9
50
711.2
725.4
739.6
753.8
768.1
782.3
796.5
810.7
825.0
839.2
60
853.4
867.6
881.8
896.1
910.3
924.5
938.7
953.0
967.2
981.4
70
995.6
1010
1024
1038
1053
1067
1081
1095
1109
1124
80
1138
1152
1166
1181
1195
1209
1223
1237
1252
1266
90
1280
1294
1309
1323
1337
1351
1365
1380
1394
1408
100
1422
1437
1451
1465
1479
1493
1508
1522
1536
1550
110
1565
1579
1593
1607
1621
1636
1650
1664
1678
1693
120
1707
1721
1735
1749
1764
1778
1792
1806
1821
1835
130
1849
1863
1877
1892
1906
1920
1934
1949
1963
1977
140
1991
2005
2020
2034
2048
2062
2077
2091
2105
2119
150
2134
2148
2162
2176
2190
2205
2219
2233
2247
2262
160
2276
2290
2304
2318
2333
2347
2361
2375
2389
2404
170
2418
2432
2446
2460
2475
2489
2503
2518
2532
2546
180
2560
2574
2589
2603
2617
2631
2646
2660
2674
2688
190
2702
2717
2731
2745
2759
2773
2788
2802
2816
2830
200
2845
2859
2873
2887
2901
2916
2930
2944
2958
2973
210
2987
3001
3015
3030
3044
3058
3072
3086
3101
3115
220
3129
3143
3158
3172
3186
3200
3214
3229
3243
3257
230
3271
3286
3300
3314
3328
3343
3357
3371
3385
3399
240
3414
3428
3442
3456
3470
3485
3499
3513
3527
3542
00-20
FOREWORD
CONVERSION TABLE
Temperature Fahrenheit-Centigrade Conversion ; a simple way to convert a Fahrenheit temperature reading into a Centigrade temperature reading or vice versa is to enter the accompanying table in the center or boldface column of figures. These figures refer to the temperature in either Fahrenheit or Centigrade degrees. If it is desired to convert from Fahrenheit to Centigrade degrees, consider the center column as a table of Fahrenheit temperatures and read the corresponding Centigrade temperature in the column at the left. If it is desired to convert from Centigrade to Fahrenheit degrees, consider the center column as a table of Centigrade values, and read the corresponding Fahrenheit temperature on the right. 1°C = 33.8°F
°C
°F
°C
°F
°C
°F
°C
°F
–40.4 –37.2 –34.4 –31.7 –28.9
–40 –35 –30 –25 –20
–40.0 –31.0 –22.0 –13.0 –4.0
–11.7 –11.1 –10.6 –10.0 –9.4
11 12 13 14 15
51.8 53.6 55.4 57.2 59.0
7.8 8.3 8.9 9.4 10.0
46 47 48 49 50
114.8 116.6 118.4 120.2 122.0
27.2 27.8 28.3 28.9 29.4
81 82 83 84 85
117.8 179.6 181.4 183.2 185.0
–28.3 –27.8 –27.2 –26.7 –26.1
–19 –18 –17 –16 –15
–2.2 –0.4 1.4 3.2 5.0
–8.9 –8.3 –7.8 –7.2 –6.7
16 17 18 19 20
60.8 62.6 64.4 66.2 68.0
10.6 11.1 11.7 12.2 12.8
51 52 53 54 55
123.8 125.6 127.4 129.2 131.0
30.0 30.6 31.1 31.7 32.2
86 87 88 89 90
186.8 188.6 190.4 192.2 194.0
–25.6 –25.0 –24.4 –23.9 –23.3
–14 –13 –12 –11 –10
6.8 8.6 10.4 12.2 14.0
–6.1 –5.6 –5.0 –4.4 –3.9
21 22 23 24 25
69.8 71.6 73.4 75.2 77.0
13.3 13.9 14.4 15.0 15.6
56 57 58 59 0
132.8 134.6 136.4 138.2 140.0
32.8 33.3 33.9 34.4 35.0
91 92 93 94 95
195.8 197.6 199.4 201.2 203.0
–22.8 –22.2 –21.7 –21.1 –20.6
–9 –8 –7 –6 –5
15.8 17.6 19.4 21.2 23.0
–3.3 –2.8 –2.2 –1.7 –1.1
26 27 28 29 30
78.8 80.6 82.4 84.2 86.0
16.1 16.7 17.2 17.8 18.3
61 62 63 64 65
141.8 143.6 145.4 147.2 149.0
35.6 36.1 36.7 37.2 37.8
96 97 98 99 100
204.8 206.6 208.4 210.2 212.0
–20.0 –19.4 –18.9 –18.3 –17.8
–4 –3 –2 –1 0
24.8 26.6 28.4 30.2 32.0
–0.6 0 0.6 1.1 1.7
31 32 33 34 35
87.8 89.6 91.4 93.2 95.0
18.9 19.4 20.0 20.6 21.1
66 67 68 69 70
150.8 152.6 154.4 156.2 158.0
40.6 43.3 46.1 48.9 51.7
105 110 115 120 125
221.0 230.0 239.0 248.0 257.0
–17.2 –16.7 –16.1 –15.6 –15.0
1 2 3 4 5
33.8 35.6 37.4 39.2 41.0
2.2 2.8 3.3 3.9 4.4
36 37 38 39 40
96.8 98.6 100.4 102.2 104.0
21.7 22.2 22.8 23.3 23.9
71 72 73 74 75
159.8 161.6 163.4 165.2 167.0
54.4 57.2 60.0 62.7 65.6
130 135 140 145 150
266.0 275.0 284.0 293.0 302.0
–14.4 –13.9 –13.3 –12.8 –12.2
6 7 8 9 10
42.8 44.6 46.4 48.2 50.0
5.0 5.6 6.1 6.7 7.2
41 42 43 44 45
105.8 107.6 109.4 111.2 113.0
24.4 25.0 25.6 26.1 26.7
76 77 78 79 80
168.8 170.6 172.4 174.2 176.0
68.3 71.1 73.9 76.7 79.4
155 160 165 170 175
311.0 320.0 329.0 338.0 347.0
00-21
FOREWORD
UNITS
UNITS In this manual, the measuring units are indicated with Internatinal System of units (SI). As for reference, conventionally used Gravitational System of units are indicated in parentheses { Example: N {kg} Nm {kgm} MPa {kg/cm2} kPa {mmH2O} kPa {mmHg} kW/rpm {HP/rpm} g/kWh {g/HPh}
00-22
}.
01 GENERAL Specifiaction dimensions drawing ...................... 01-2 Working range drawing ....................................... 01-3 Specifications ...................................................... 01-4 Weight table ........................................................ 01-7 List of lubricants and coolant .............................. 01-9
PC78MR-6
01-1
GENERAL
SPECIFICATION DIMENSIONS DRAWING
SPECIFICATION DIMENSIONS DRAWING
Item
Unit
PC78MR-6 Steel shoe spec.
Road liner spec.
8,270
8,300
Machine weight (with blade)
kg
Bucket capacity
m³
0.28
Engine model
—
KOMATSU S4D95LE-3-A Diesel engine
kW {HP}/rpm
40.5 {54.0}/1,850
Rated engine output A
Overall length
mm
6,200
6,230
B
Overall height
mm
2,730
2,750
C
Overall width
mm
2,330
D
Shoe width
mm
450
E
Tail swing radius
mm
1,310
F
Overall length of track
mm
G
Distance between tumbler centers
mm
01-2
2,840
2,900 2,235
Minimum ground clearance
mm
Travel speed (Low/High)
km/h
360 2.8/4.2
400
Continuous swing speed
rpm
10.0
PC78MR-6
GENERAL
WORKING RANGE DRAWING
WORKING RANGE DRAWING
Working range (mm)
Steel shoe spec.
A
Max. digging reach
6,960
B
Max. digging depth
4,160
C
Max. digging height
6,570
D
Max. vertical wall depth
2,900
E
Max. dumping height
4,515
Min. swing radius of work equipment
2,775
Min. swing radius at boom swinging
2,125
G
Max. reach at ground level
6,750
H
Max. blade lifting height
380
I
Max. blade lowering depth
245
F
PC78MR-6
01-3
GENERAL
SPECIFICATIONS
Dimension
Machine model
PC78MR-6
Serial Number
1001 and up
Bucket capacity
m3
0.28
Machine weight
kg
8,270 (8,300)
Max. digging depth
mm
4,160
Max. vertical wall depth
mm
2,900
Max. digging reach
mm
6,960
Max. reach at ground level
mm
6,750
Max. digging height
mm
6,570
Max. dumping height
mm
4,515
Boom swing (left side/right side)
mm
580/930
Max. blade lifting height
mm
380
Max. blade lowering depth
mm
245
kN {kg}
61.3 {6,250}
Continuous swing speed
rpm
10.0
Max. slope angle for swing
deg.
16.0
Travel speed (Low/High)
km/h
2.8/4.2
Gradeability
deg.
35
Ground pressure
{kg/cm2}
Working range
Performance
SPECIFICATIONS
Max. digging force (Bucket)
kPa
37.3 {0.38}
Overall length (for transport)
mm
6,200
Overall width
mm
2,330
Overall height (for transport)
mm
2,730 (2,750)
Overall height (for operation)
mm
2,710 (2,750)
Ground clearance of counterweight
mm
735 (780)
Min. ground clearance
mm
360 (400)
Tail swing radius
mm
1,310
Min. swing radius of work equipment (at boom swinging)
mm
2,125
Height of work equipment at min. swing radius
mm
5,210 (5,230)
Overall width of track
mm
2,320
Overall length track
mm
2,840 (2,900)
Distance between tumbler centers
mm
2,235
Track gauge
mm
1,870
Machine cab height
mm
1,745 (1,795)
Blade width × height
mm
2,320 × 470
Figures (steel shoe specification) are common to the all specifications unless otherwise specified. ( ) Figures in ( ): Road liner specification
01-4
PC78MR-6
GENERAL
SPECIFICATIONS
Machine model
PC78MR-6
Serial Number
1001 and up
Model
S4D95LE-3-A
Type
4-cycle, water-cooled, in-line, direct injection
No. of cylinders - bore × stroke
mm
4-95 × 115
l {cc}
3.26 {3,260}
kW/rpm {HP/rpm} Nm/rpm {kgm/rpm}
40.5/1,850 {54.0/1,850} 337/1,500 {24.2/1,500}
Max. speed at no load
rpm
2,020
Min. speed at no load
rpm
1,130
Min. fuel consumption
g/kWh {g/HPh}
227 {169}
Total displacement
Performance
Engine
Rated output Max. torque
Starting motor
24 V, 3.0 kw
Alternator
24 V, 25 A
Battery
12 V, 48 Ah × 2 (55D26R) 1 on each side
Track roller
5 on each side
Track shoe
Control valve Hydraulic motor
Hydraulic system
CF29-3
Carrier roller
Hydraulic pump
Undercarriage
Type of radiator core
Assembly-type triple grouser, 39 on each side Assembly-type road liner, 39 on each side Unit-type rubber crawler Variable-capacity piston pump × 1 Gear pump × 2
(Steel shoe) (Road liner) (Rubber shoe)
Type × No. Discharge Set pressures (Work equipment, travel) (Swing, blade) (Control) Type × No. Control method Travel motor Swing motor
Hydraulic tank Hydraulic oil filter Oil cooler
PC78MR-6
l {cc}
80×2+60+12.7
MPa {kg/cm2}
26.5 {270} 21.1 {215} 3.1 {32} 9-spool type × 1 Hydraulically assisted Variable-capacity piston motor (with brake valve, parking brake) × 2 Fixed-capacity piston motor (with safety valve, pivot shaft brake) × 1 Box-shaped, open Tank return side Air-cooled
01-5
GENERAL
SPECIFICATIONS
Machine model
PC78MR-6
Serial Number
1001 and up
Bucket cylinder Blade cylinder
Boom swing cylinder
Work equipment cylinder
Hydraulic system
Arm cylinder
Boom cylinder
Type
01-6
Reciprocating piston
Inside diameter of cylinder
mm
115
Diameter of piston rod
mm
65
Stroke
mm
988
Max. distance between pinsmm
mm
2,393
Min. distance between pinsmm
mm
1,405
Type
mm
Reciprocating piston
Inside diameter of cylinder
mm
100
Diameter of piston rod
mm
60
Stroke
mm
865
Max. distance between pins
mm
2,193
Min. distance between pins
mm
1,328
Type
mm
Reciprocating piston
Inside diameter of cylinder
mm
90
Diameter of piston rod
mm
55
Stroke
mm
710
Max. distance between pins
mm
1,765
Min. distance between pins
mm
1,055
Type
mm
Reciprocating piston
Inside diameter of cylinder
mm
120
Diameter of piston rod
mm
60
Stroke
mm
658
Max. distance between pins
mm
1,687
Min. distance between pins
mm
1,029
Type
mm
Reciprocating piston
Inside diameter of cylinder
mm
Diameter of piston rod
mm
65
Stroke
mm
130
Max. distance between pins
mm
679
Min. distance between pins
mm
549
130
PC78MR-6
GENERAL
WEIGHT TABLE
WEIGHT TABLE
k This mass list is for reference in handling or transporting these components. Unit: kg Machine model
PC78MR-6
Serial Number
1001 and up
Engine assembly (without water and oil)
403
• Engine (without water and oil)
300
• Engine mount
30
• PTO
7
• Hydraulic pump
66
Cooling assembly (without coolant and oil)
29
• Radiator (without coolant)
6.3
• Oil cooler (without oil)
5.2
Revolving frame
1,220
Operator's cab
260
Operator's seat
18
Fuel tank (without fuel)
8.3
Hydraulic tank (without hydraulic oil)
70
Control valve
62
Counterweight
950
Additional counterweight
220
Swing motor (Including brake valve)
22
Swing circle
104
Swing machinery
47
Center swivel joint
16
Track frame assembly (without track shoe) • Track frame
1,067 [1,048] 704
• Idler assembly
54 x 2
• Recoil spring assembly
40 x 2
• Carrier roller
3.4 x 2
• Track roller
13 x 10
• Travel motor (with reduction gears)
81 x 2
• Sprocket
19 x 2
Figures (steel shoe specification) are common to the all specifications unless otherwise specified. [ ] Figures in [ ]: Rubber shoe specification
PC78MR-6
01-7
GENERAL
WEIGHT TABLE
Unit: kg Machine model
PC78MR-6
Serial Number
1001 and up
Track shoe assembly • City pad shoe (450 mm)
410 X 2
• Road liner (450 mm)
450 X 2
• Rubber shoe (450 mm)
385 X 2
• Triple grouser (600 m)
495 X 2
Boom assembly
365
Swing bracket
234
Arm assembly
147
Bucket link assembly
56
Bucket assembly (with side cutter)
210
Blade assembly
374
Boom cylinder assembly
95
Arm cylinder assembly
72
Bucket cylinder assembly
51
Boom swing cylinder assembly
65
Blade cylinder assembly
46
Figures are common to the all specifications unless otherwise specified.
01-8
PC78MR-6
GENERAL
LIST OF LUBRICANTS AND COOLANT
LIST OF LUBRICANTS AND COOLANT
RESERVOIR
KIND OF FLUID
AMBIENT TEMPERATURE –22 –30
–4 –20
14 –10
32 0
50 10
68 20
86 30
104 40
122°F 50°C
SAE 30 SAE 10W
Engine oil pan
SAE 10W-30 SAE 15W-40 Swing machinery case Final drive case PTO gear case
Engine oil SAE 30
SAE 10 Hydraulic system
SAE 10W-30 SAE 15W-40 ASTM D975 No. 2
Fuel tank
Diesel fuel *1
Greasing system
Diesel fuel
Cooling system
Water
NLGI No. 2 Add antifreeze
Unit: l
*1: ASTM D975 No. 1 Reservoir
PC78MR-6 Specified capacity
Refill capacity
Engine oil pan
7.5
7.0
PTO gear case
0.4
0.4
Swing machinery case
2.0
2.0
Final drive case (each)
1.3
1.3
Hydraulic system
120
64
Fuel tank
125
—
Cooling system
10.5
—
PC78MR-6
01-9
10 STRUCTURE, FUNCTION AND MAINTENANCE STANDARD PTO ........................................................................... 10- 2 Cooling system .......................................................... 10- 3 Power train system .................................................... 10- 4 Swing circle ............................................................... 10- 5 Swing machinery ....................................................... 10- 6 Track frame and idler cushion ................................... 10- 8 Idler ........................................................................... 10-10 Track roller..................................................................10-11 Carrier roller .............................................................. 10-12 Sprocket .................................................................... 10-13 Track shoe................................................................. 10-14 Arrangement of hydraulic components...................... 10-19 Hydraulic tank and oil filter ........................................ 10-20 Center swivel joint ..................................................... 10-21 Travel motor .............................................................. 10-22 Work equipment cylinder ........................................... 10-30 Solenoid valve ........................................................... 10-34 Multi-Control Valve .................................................... 10-40 Accumulator for Brake ............................................... 10-41 Hydraulic pump ......................................................... 10-42 Control valve ............................................................. 10-56 CLSS ......................................................................... 10-68 Swing motor ............................................................ 10-100 Work equipment and swing PPC valve ................... 10-108 Travel PPC valve......................................................10-114 Boom swing PPC valve, blade PPC valve ...............10-118 Boom hydraulic anti-burst valve (For EU spec.) ... 10-121-1 Work equipment ...................................................... 10-122 Dimensions of each part of work equipment ........... 10-124 Air conditioner piping (Optional) .............................. 10-128 Electric control system ............................................ 10-129 System components ................................................ 10-146 Monitor system ........................................................ 10-154 Sensors ................................................................... 10-158
PC78MR-6
10-1 (1)
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
PTO
PTO
1. 2. 3. 4. 5. 6. 7.
Drain plug Coupling Flywheel Pump case Cage Level plug Breather/Oil filler plug
10-2
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
COOLING SYSTEM
COOLING SYSTEM
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.
Fan guard Radiator inlet hose Drain valve Radiator outlet hose Radiator cap Oil cooler Radiator Shroud Oil cooler inlet Reservoir tank Oil cooler outlet
PC78MR-6
SPECIFICATIONS Radiator
Oil cooler
Type of core
CF29-3
CF40-1
Fin pitch (mm)
4.0/2
4.5/2
Total heat dissipation area (m2)
16.53
6.15
Pressure valve cracking pressure (kPa {kg/cm²})
88.3±14.7 (0.9±0.15)
–
Vacuum valve cracking pressure (kPa {kg/cm²})
4.9 (0.05)
–
10-3
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
POWER TRAIN SYSTEM
POWER TRAIN SYSTEM
1. 2. 3. 4. 5. 6. 7. 8.
Idler Control valve Center swivel joint Swing motor Travel motor Control pump (for pilot control) Hydraulic pump (for swing and blade) Hydraulic pump (For travel and work equipment) 9. Engine
10-4
10. 11. 12. 13. 14. 15. 16. 17.
Boom RAISE stop EPC valve Arm IN stop EPC valve Left offset stop EPC vaolve Swing holding brake solenoid valve 2-stage travel speed selector solenoid valve PPC lock solenoid valve Swing machinery Swing circle
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SWING CIRCLE
SWING CIRCLE
Unit: mm
2. 3. 4. 5. 6. 7.
No.
Item
1
Axial clearance of bearing
Greasing for swing circle bearing Greasing for swing circle pinion Outer race Inner race Ball Seal
PC78MR-6
Criteria
Remedy
Standard clearance
Allowable clearance
0.20 – 0.80
2.0
Replace
a. Position of inner race soft zone b. Position of outer race soft zone Specifications Reduction ratio
80/10=8.0
Grease
G2-LI
Quantity of grease ( )
5.5
10-5
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SWING MACHINERY
SWING MACHINERY
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.
Swing pinion (Number of teeth: 10) Swing machinery case No. 2 planetary carrier Ring gear (Number of teeth: 58) No. 2 sun gear (Number of teeth: 14) No. 1 planetary carrier No. 1 sun gear (Number of teeth: 14) Swing motor Oil filler Level gauge No. 1 planetary gear (Number of teeth: 22) No. 2 planetary gear (Number of teeth: 22) Drain plug
10-6
Specification Reduction ratio
(14+58)/14X(14+58)/14 = 26.45
Swing reduction ratio
26.45X8.0 = 211.59
Swing speed (rpm)
10
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SWING MACHINERY
Unit: mm No.
Item
1
Backlash between swing motor shaft and No. 1 sun gear
2
Criteria
Remedy
Standard clearance
Allowable clearance
0.03 – 0.11
—
Backlash between No. 1 sun gear and No. 1 planetary gear
0.10 – 0.27
0.6
3
Backlash between No. 1 planetary gear and ring gear
0.12 – 0.38
0.6
4
Backlash between No. 1 planetary carrier and No. 2 sun gear
0.10 – 0.26
—
5
Backlash between No. 2 sun gear and No. 2 planetary gear
0.10 – 0.27
0.6
6
Backlash between No. 2 planetary gear and ring gear
0.12 – 0.38
0.6
7
Backlash between No. 2 planetary carrier and swing pinion
0.07 – 0.21
—
8
Backlash between swing pinion and swing circle
0.27 – 0.83
2.0
9
Wear of sliding surface of swing pinion collar against oil seal
PC78MR-6
Replace
Basic dimension 75
Allowance 0 - 0.074
Allowable Limit 74.8
Plating with hard chromium or replace
10-7
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRACK FRAME AND IDLER CUSHION
TRACK FRAME AND IDLER CUSHION
10-8
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRACK FRAME AND IDLER CUSHION
Unit: mm No.
1
2
Item
Criteria Basic dimension
Allowable limit
Vertical width of Track frame idler guide Idler support
74
78
73
69
Track frame Lateral width of idler guide Idler support
158
162
Overlay
152
Overlay or replace
156 Basic dimension
3
Remedy
Recoil spring
Overlay Overlay or replace
Allowable limit
Free length
Installed length
Installed load
Free length
Installed load
Road liner, steel shoe
412
323
47.4 kN {4,835 kg}
402
42.2 kN {4,305 kg}
Rubber shoe
412
283
69.2 kN {7,061 kg}
402
61.6 kN {6,284 kg}
Replace
4. 5. 6. 7. 8. 9. 10. 11.
Idler Track frame Carrier roller Travel motor Sprocket Track roller Track shoe Idler cushion 11a.Support 11b.Yoke 11c.Recoil spring 11d.Cylinder 11e.Collar 11f. Lubricator 12. Idler guard (Road liner specification, steel shoe specification) 13. Bracket to secure machine body for transportation (for USA spec. only) Specification Grease
G2-LI
Quantity of grease (cc)
96 (Steel shoe, road liner) 233 (Rubber shoe)
PC78MR-6
10-9
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
IDLER
IDLER
Unit: mm No. 1
Item Outside diameter of projected part
2
Outside diameter of tread
3
Depth of tread
4
Width of projected part
5 6
7
8
9
Criteria Basic dimension
Remedy Allowable limit
460
—
415
407
22.5
26.5
43
37
Overall width
100
92
Width of tread
28.5
32
Clearance between idler shaft and bushing
Interference between idler and bushing Side clearance of idler (Each side)
10
Thickness of tread (at center of width of tread)
—
Quantity of oil
10-10
Basic dimension 44 Basic dimension 50
Allowance Shaft
Hole
-0.250 -0.290
+ 0.062 0
Allowance Shaft
Hole
+0.117 +0.087
+0.025 0
Standard clearance
Overlay or replace
Standard clearance
Allowable clearance
0.250 – 0.352
1.5
Standard interference
Allowable interference
0.062 – 0.117
—
Replace
Allowable clearance
0.190 – 0.395
1.5
Basic dimension
Allowable limit
13.8
9.8 60 cc (Engine oil: SAE30CD)
Overlay or replace —
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRACK ROLLER
TRACK ROLLER
Unit: mm No.
Item
Criteria Basic dimension
Remedy Allowable limit
1
Outside diameter of projected part
149
—
2
Outside diameter of tread
120
113
3
Width of flange
43
4
Overall width
129
—
—
5
Width of tread
43
47.3
Overlay or replace
6
Clearance between idler shaft and bushing
7
8
Interference between idler and bushing Side clearance of track roller (Each side)
9
Thickness of tread (at center of width of tread)
—
Quantity of oil
PC78MR-6
38
Shaft
Hole
-0.250 -0.270
+ 0.075 - 0.025
Allowance
Basic dimension 48
36.6
Allowance
Basic dimension
Overlay or replace
Shaft
Hole
+0.117 +0.087
+0.030 0
Standard clearance
Standard clearance
Allowable clearance
0.225 – 0.345
1.5
Standard interference
Allowable interference
0.057 – 0.117
—
Replace
Allowable clearance
0.38 – 0.73
1.5
Basic dimension
Allowable limit
36
32.5 210 – 230 cc (Gear oil: G0140)
Overlay or replace —
10-11
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CARRIER ROLLER
CARRIER ROLLER
Unit: mm No.
Item
1
Outside diameter of tread
2
Width of tread
3
Interference between shaft and bearing
4
Interference between roller and bearing
5
Thickness of tread
—
Quantity of oil
10-12
Criteria Basic dimension
Remedy Allowable limit
82 100
— Allowance
Basic dimension
Overlay or replace
72
—
Shaft
Hole
Standard interference
Allowable interference
30
+0.009 -0.004
0 - 0.010
-0.004 – 0.019
—
62
0 - 0.013
+ 0.018 - 0.012
-0.031 – 0.012
—
Basic dimension
Allowable limit
10
5
47 – 52 cc (Grease: ALVANIA EP-2)
Replace
Overlay or replace —
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SPROCKET
SPROCKET
Unit: mm No.
Item
Criteria Basic dimension
1
Wear of root diameter
Allowance
433.004
+1.0 -2.0 ±2.0
Remedy Allowable limit 421
2
Wear of tip diameter
483.7
3
Wear of dip width
28
-
23
4
Wear of root width
38
+0.5 -2.5
33
5
Thickness of root
84.002
+0.475 -1.150
78
PC78MR-6
472
Overlay or replace
10-13
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRACK SHOE
TRACK SHOE CITY PAD SHOE, ROAD LINER, AND TRIPLE SHOE
*1. City pad shoe Triple shoe (OPT)
*2. Road liner (OPT) a Part P is the link on the press fitting side of bushing.
10-14
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRACK SHOE
Unit: mm No.
Item
Criteria Basic dimension
Allowable limit
154.25
157.25
41.2
37.2
Height of link
74
70
Thickness of link (Press fitting part of bushing)
20
16
1
Link pitch
2
Outside diameter of bushing
3 4 5 6
Shoe bolt pitch
Repair or replace
73
Replace
57
8 Link
10
Inside width
45
Overall width
30
Width of tread
26.3
11
Projection of pin
12
Projection of regular bushing
3.15
13
Overall length of pin
131
14
Overall length of bushing (Master bushing)
74.6
15
Thickness of bushing
16
Thickness of spacer
17 18
Reverse or replace
89
7
9
Remedy
Press fitting pressure
*19
Repair or replace
3
Basic dimension
Adjust or replace Allowable limit
8.4
4.4 —
Bushing
19.6 – 98.1 kN {2 – 10 ton}
Regular pin
49.0 – 117.7 kN {5 – 12 ton}
Master pin
—
39.2 – 78.5 kN {4 – 8 ton}
Items marked with * are for the dry track.
PC78MR-6
10-15
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRACK SHOE
Unit: mm No.
Item
Criteria Tightening torque (Nm {kgm}) a. Regular link
Shoe bolt 20 b. Master link
Retightening angle (deg.)
• City pad • Triple
117.7 ± 19.6 {12 ± 2}
90 ± 10
• Road liner
117.7 ± 19.6 {12 ± 2}
60 ± 10 (Torque after retightening) Min. 343 Nm {35 kgm}
Tightening torque
Retightening angle (deg.)
Lower limit torque
—
—
—
Number of shoes (Each side)
21
22
23
*24
*25
26
39
Interference between regular pin and link Clearance between regular pin and bushing
Interference between master pin and link
Clearance between master pin and bushing
Hole
41
+0.214 +0.174
+0.062 0
0.112 – 0.214
24
+0.150 0
-0.198 -0.250
0.198 – 0.400
Allowance
24
Shaft
Hole
+0.150 0
+0.830 +0.330
Standard clearance 0.180 – 0.830 Adjust or replace
Allowance
Basic dimension 24
Shaft
Hole
+0.020 -0.020
-0.198 -0.250
Standard interference 0.178 – 0.270
Allowance
Basic dimension
Road liner
Standard interference
Shaft
Basic dimension
24
Retighten
—
Allowance
Basic dimension
Number of shoes (Each side)
Height of grouser
Remedy
Shaft
Hole
-0.150 -0.250
+0.630 +0.230
Standard clearance 0.380 – 0.880
Basic dimension
Allowable limit
42
19
Replace
Items marked with * are for the dry track.
10-16
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRACK SHOE
TRIPLE SHOE AND CITY PAD SHOE
Unit: mm No.
Item
1
Height of grouser
2
Overall height of shoe
3
Thickness of plate
4 5
Length of base of grouser
6 7
Criteria
Remedy
Basic dimension
Allowable limit
20
12
26
18 6 20
Overlay or replace
16 14
Length of upper side of grouser
8
PC78MR-6
10 12
10-17
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRACK SHOE
RUBBER SHOE (OPTIONAL)
Unit: mm No.
Item
1
Wear of lug height
2
Wear of roller guide
3
Wear of meshing part of sprocket
10-18
Criteria
Remedy
Basic dimension
Allowable limit
30
5
42
58
Replace
Basic dimension
Allowance
Allowable limit
22.5
±0.5
27
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ARRANGEMENT OF HYDRAULIC COMPONENTS
ARRANGEMENT OF HYDRAULIC COMPONENTS
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.
Bucket cylinder Arm cylinder Boom cylinder Boom swing cylinder Hydraulic tank Control valve Swing motor Hydraulic pump Oil cooler Travel motor Left work equipment PPC valve
PC78MR-6
12. 13. 14. 15. 16. 17. 18. 19. 20.
Blade PPC valve Right work equipment PPC valve Center swivel joint Service PPC valve (Machine to which attachments can be installed) Travel PPC valve 6-spool solenoid valve Boom swing PPC valve Blade cylinder Boom hydraulic anti-burst valve (For EU spec.)
10-19 (1)
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
HYDRAULIC TANK AND OIL FILTER
HYDRAULIC TANK AND OIL FILTER
1. 2. 3. 4. 5. 6. 7.
Hydraulic tank Sight gauge Strainer Drain plug Filter Bypass valve Oil filler cap
10-20
Specification Tank capacity ( )
80
Quantity of oil in tank ( )
64
Bypass valve set pressure (kPa {kg/cm²})
0.15 ± 0.03 {1.53 ± 0.3}
Pressure valve cracking pressure (kPa {kg/cm²})
38 ± 15 {0.39 ± 0.15}
Vacuum valve cracking pressure (kPa {kg/cm²})
0–5 {0 – 0.05}
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CENTER SWIVEL JOINT
CENTER SWIVEL JOINT
A1: From right travel control valve
A2: To right travel motor
B1: From right travel control valve
B2: To right travel motor
C1: From left travel control valve
C2: To left travel motor
D1: From left travel control valve
D2: To left travel motor
E1: From blade control valve
E2: To blade cylinder bottom
F1: From blade control valve
F2: To blade cylinder head
G1: From 2-stage travel speed selector solenoid valve
G2: To 2-stage travel speed selector solenoid valve
DR1: To tank
DR2: From travel motor drain port
1. Cover 2. Rotor
3. Slipper seal 4. Shaft Unit: mm
No. 5
Item Clearance between rotor and shaft
PC78MR-6
Criteria Basic dimension 70
Remedy
Standard clearance
Allowable clearance
0.056 – 0.105
0.111
Replace
10-21
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRAVEL MOTOR
TRAVEL MOTOR
A. B. D. P.
From travel control valve From travel control valve To tank From 2-stage travel speed selector solenoid valve
10-22
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13.
Check valve Counterbalance valve Valve plate Cylinder Brake piston Plate Disc Piston Swash plate Regulator piston RV gear RV gear Case
PC78MR-6
TRAVEL MOTOR
14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.
Shaft Drive gear Cover Crankshaft Drain plug Driven gear Pivot Spindle Floating seal End cover Regulator valve Check valve
10-23
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRAVEL MOTOR
Specification Model Theoretical displacement (cm³/rev) Rated speed
GM09VN-E Hi
24.1
Lo
36.3
Hi
3,211
Lo
2,154
Brake releasing pressure (MPa {kg/cm²})
0.47 {4.8}
Speed changeover pressure (MPa {kg/cm²})
2.94 {30}
Reduction ratio
66.5
Outline
1. Reduction gears The reduction gears consists of spur gear unit (1a) and differential gear unit (1b) which uses pericycloid gears and converts the high speed revolution of the hydraulic motor into low-speed and high-torque revolution. 2. Hydraulic motor The hydraulic motor is a swash plate-type axial piston motor, which converts the power of the hydraulic oil sent from the hydraulic pump into revolution.
4. 2-stage travel speed changeover mechanism The 2-stage travel speed changing mechanism consists of a changeover valve and a piston, which change the displacement of the hydraulic motor to either of 2 stages. 5. Parking brake The parking brake is a friction plate brake, which is built as a part of the hydraulic motor.
3. Brake valve The brake valve consists of various valves and has functions of stopping the hydraulic motor smoothly, preventing the hydraulic motor from running away, and preventing generation of abnormally high pressure when the hydraulic motor is stopped suddenly.
10-24
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRAVEL MOTOR
OPERATION Operation of motor At low speed (With swash plate angle at maximum)
1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
2-stage travel speed selector solenoid valve Regulator valve Spring Check valve End cover Regulator piston Swash plate Pump merge-divider valve Travel control valve Brake valve
• • •
• •
PC78MR-6
Since 2-stage travel speed selector solenoid valve (1) is de-energized, the hydraulic oil from the control pump does not flow into port Pi. Accordingly, regulator valve (2) is pressed to the left by spring (3). Under this condition, the main hydraulic oil from the control valve pushes check valve (4) and flows into end cover (5) and then is shut off by regulator valve (2). The hydraulic oil in control chamber (a) flows through passage (b) of regulator valve (2) into the motor case. As a result, swash plate (7) is pushed toward the maximum swash plate angle by the main hydraulic oil in chamber (P) of the cylinder and the motor capacity is increased to the maximum and the travel speed lowers.
10-25
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRAVEL MOTOR
At high speed (With swash plate angle at minimum)
1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
2-stage travel speed selector solenoid valve Regulator valve Spring Check valve End cover Regulator piston Swash plate Pump merge-divider valve Travel control valve Brake valve
10-26
•
•
•
If 2-stage travel speed selector solenoid valve (1) is energized, the pilot pressure from the control pump flows into port Pi and pushes regulator valve (2) to the right. Accordingly, the main hydraulic oil from the control valve flows through passage (c) of regulator valve (2) into control chamber (a) and pushes regulator piston (6) to the left. As a result, swash plate (7) is pushed toward the minimum swash plate angle and the motor capacity is decreased to the minimum and the travel speed rises.
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRAVEL MOTOR
Operation of brake valve
Operation when oil is supplied
•
•
The brake valve consists of check valves (1a) and (1b) and counterbalance valve spool (2) as shown in the following figure.
If the travel lever is operated, the hydraulic oil from the control valve flows in port PA, pushes valve (1a) open, and flows through motor input port MA to motor outlet port MB. At the same time, the hydraulic oil also flows through orifice c of spool (2) to chamber D. If its pressure becomes higher than the pressure of spring (3), spool (2) is pushed to the left. As a result, port MB is connected to port PB and the motor outlet side opens and the motor starts revolution. Since port PA is connected to port E, too, the hydraulic oil operates parking brake piston (4) to release the parking brake force.
Function •
When the machine travels downhill, its speed may become higher than the motor speed because of its momentum. If the engine speed is low at this time, the motor runs idle and the machine runs away, and this situation is very dangerous. The brake valve prevents this phenomenon and limits the travel speed according to the engine speed (pump discharge).
PC78MR-6
10-27
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRAVEL MOTOR
Operation when oil is shut off
Operation of brake during downhill travel
•
•
• • •
If the control lever is returned to neutral, the hydraulic oil from the control valve is shut off and spool (2) is returned to the right by the reaction force of spring (3). At this time, the oil flows through orifice (c) of chamber D into port PA and back pressure is generated by the throttle effect of orifice (c). This back pressure controls the speed of spool (2) returning to the right. Even after the hydraulic oil in port PA is shut off, the motor continues revolution by inertia. At this time, the returning oil is reduced gradually according to the changing speed and shape of spool (2) to stop the motor smoothly. The motor continues revolution by inertia and can cause cavitation. Since valve (1a) is operated by very slight negative pressure, however, it opens ports PA and MA to prevent cavitation.
10-28
If the machine starts running away while traveling downhill, the motor revolves idle and the pressure on the motor inlets side lowers, then the pressure in chamber D also lowers through orifice (c). If the pressure in chamber D lowers below the pressure of spring (3), spool (2) is pushed back to the right. At this time, the oil in chamber G flows through orifice (f) into port PB. The throttle effect of orifice (f) generates back pressure, and spool (2) returns to the right to control the returning speed of spool (2). Port MB on the outlet side is narrowed. As a result, the pressure on the outlet side rises and revolving resistance is generated in the motor to prevent the machine from running away. To put it concretely, spool (2) moves to a position at which the machine weight and the pressure on the inlet side are balanced with the pressure at port MB on the outlet side to narrow the outlet circuit. Consequently, the speed is controlled according to the pump discharge.
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRAVEL MOTOR
Operation of parking brake When travel lever is operated • If the travel lever is operated, the hydraulic oil from the pump moves spool (1) to the left and flows through port E into chamber A of brake piston (2), then pushes brake piston (2) to the left. • As a result, the pressing force of spring (5) given to plate (3) and disc (4) is lost, then plate (3) and disc (4) are separated and the brake force is released.
PC78MR-6
When travel lever is set to neutral position • If the travel lever is set to the neutral position, the hydraulic oil from the pump is shut off. The hydraulic oil in chamber (a) of brake piston (2) is drained into the case and piston (2) is pushed to the right by spring (5). As a result, plate (3) and disc (4) are pressed and the braking force is applied.
10-29
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
WORK EQUIPMENT CYLINDER
WORK EQUIPMENT CYLINDER Boom cylinder
Arm cylinder
Bucket cylinder
10-30
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
WORK EQUIPMENT CYLINDER
Boom swing cylinder
Blade cylinder
PC78MR-6
10-31
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
WORK EQUIPMENT CYLINDER
Unit: mm No.
Item
Criteria Cylinder name
1
Clearance between piston rod and bushing
Clearance between piston rod support shaft and bushing
2
3
Clearance between cylinder bottom support shaft and bushing
5
Tightening torque of cylinder piston
10-32
Shaft
Hole
Standard clearance
Allowable clearance
+0.250 +0.055
0.085 – 0.354
0.654
Boom
65
Arm
60
-0.030 -0.104
+0.163 +0.006
0.036 – 0.267
0.567
Bucket
55
-0.030 -0.104
+0.163 +0.006
0.036 – 0.267
0.567
Boom swing
60
-0.030 -0.104
+0.163 +0.006
0.036 – 0.267
0.567
Blade
65
-0.030 -0.104
+0.250 +0.055
0.085 – 0.354
0.654
Boom
60
-0.030 -0.100
+0.174 +0.100
0.130 – 0.274
1.0
Arm
60
-0.030 -0.100
+0.174 +0.100
0.130 – 0.274
1.0
Bucket
60
-0.030 -0.100
+0.174 +0.100
0.130 – 0.274
1.0
Boom swing
65
-0.030 -0.100
+0.174 +0.100
0.130 – 0.274
1.0
Blade
70
-0.030 -0.104
+0.174 +0.100
0.130 – 0.278
1.0
Boom
65
-0.030 -0.100
+0.174 +0.100
0.130 – 0.274
1.0
Arm
55
-0.030 -0.100
+0.174 +0.100
0.130 – 0.274
1.0
Bucket
50
-0.030 -0.100
+0.142 +0.080
0.110 – 0.242
1.0
Boom swing
65
-0.030 -0.076
+0.174 +0.100
0.130 – 0.250
1.0
Blade
70
-0.030 -0.104
+0.174 +0.100
0.130 – 0.278
1.0
Arm
Tightening torque of cylinder head
Allowance -0.030 -0.104
Boom
4
Basic dimension
Remedy
Bucket
Replace bushing
Replace pin and bushing
961 ± 96.1 Nm {98 ± 9.8 kgm} 785 ± 78.5 Nm {80 ± 8.0 kgm} Procedure 1) Tighten to 1.18 – 1.37 kNm {120 – 140 kgm}. 2) Loosen to 0 Nm {0 kgm}. 3) Tighten to 0.39 kNm {40 kgm}. 4) Control tightening of cylinder head by turning angle (Turning distance: 3.5 – 4.5 mm).
Boom swing
981 ± 98.1 Nm {100 ± 10.0 kgm}
Blade
1.030 ± 103.0 Nm {105 ± 10.5 kgm}
Boom
3.33 ± 0.33 kNm {340 ± 34.0 kgm} (2 Width across flats: 70 mm)
Arm
2.65 ± 0.26 kNm {270 ± 27.0 kgm} (2 Width across flats: 65 mm)
Bucket
2.16 ± 0.22 kNm {220 ± 22.0 kgm} (2 Width across flats: 60 mm)
Boom swing
2.6 ± 0.26 kNm {265 ± 26.0 kgm} (2 Width across flats: 70 mm)
Blade
3.14 ± 0.31 kNm {320 ± 32.0 kgm} (2 Width across flats: 75 mm)
Retighten
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SOLENOID VALVE
SOLENOID VALVE Serial No.: 1001 – 1094
10-34 (1)
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
A: A4: A5: A6: B1: B2: B3: B4: B5: B6: T: 1. 2. 3. 4. 5. 6.
SOLENOID VALVE
From control pump Plug From left work equipment PPC valve "ARM IN" From right work equipment PPC valve "BOOM RAISE" To PPC valve To 2-stage travel speed selection valve To swing holding brake Plug To control valve "ARM IN" To control valve "BOOM RAISE" To hydraulic tank Left boom swing stop EPC valve Right boom swing stop EPC valve Not used Swing holding brake solenoid valve 2-stage travel speed selector solenoid valve PPC lock solenoid valve
Solenoid valve 7. Coil (ON-OFF type) 8. Push pin 9. Valve spool 10. Return spring 11. Valve body EPC valve 12. Return spring 13. Guide 14. Valve spool 15. Push pin 16. Coil (Proportional) Check valve 17. Plug 18. Spring 19. Ball Control relief valve 20. Adjustment screw 21. Locknut 22. Guide 23. Return spring 24. Valve spool
PC78MR-6
10-35
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SOLENOID VALVE
Serial No.: 1095 and up
10-35-1 (1)
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
A: A5: A6: B1: B2: B3: B4: B5: B6: T: 1. 2. 3. 4. 5.
SOLENOID VALVE
From control pump From left work equipment PPC valve "ARM IN" From right work equipment PPC valve "BOOM RAISE" To PPC valve To 2-stage travel speed selection valve To swing holding brake Plug To control valve "ARM IN" To control valve "BOOM RAISE" To hydraulic tank Left boom swing stop EPC valve Right boom swing stop EPC valve Swing holding brake solenoid valve 2-stage travel speed selector solenoid valve PPC lock solenoid valve
Solenoid valve 6. Coil (ON-OFF type) 7. Push pin 8. Valve spool 9. Return spring 10. Valve body EPC valve 11. Return spring 12. Guide 13. Valve spool 14. Push pin 15. Coil (Proportional) Check valve 16. Plug 17. Spring 18. Ball Control relief valve 19. Adjustment screw 20. Locknut 21. Guide 22. Return spring 23. Valve spool
PC78MR-6
10-35-2 (1)
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SOLENOID VALVE
PPC LOCK SOLENOID VALVE 2-STAGE TRAVEL SPEED SELECTOR SOLENOID VALVE SWING HOLDING BRAKE SOLENOID VALVE Operation When solenoid is de-energized (circuit is broken) • While a signal current does not flow from the PPC hydraulic lock switch or travel speed boost pedal, solenoid (1) is de-energized. Accordingly, spool (2) is pressed up by spring (3). • Under this condition, port A is closed and the pilot hydraulic oil does not flow into the actuator. At the same time, the oil from the actuator is drained through ports B and T into the tank.
10-36
When solenoid is energized (circuit is made) • If a signal current flows from the PPC hydraulic lock switch or travel speed boost pedal to solenoid (1), solenoid (1) is energized. • Accordingly, spool (2) is pushed down by push pin (4). • Under this condition, the pilot hydraulic oil flows through port A, spool (2), and port B into the actuator. At the same time, port T is closed and the oil does not flow into the tank.
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SOLENOID VALVE
LEFT BOOM SWING STOP EPC VALVE RIGHT BOOM SWING STOP EPC VALVE Operation When signal current is maximum (When coil is energized and circuit pressure is maximum) • If the signal current flows from the controller into coil (1), coil (1) is energized. At this time, the thrust of coil (1) is maximum. • As a result, spool (2) is pushed down by push pin (3). • Accordingly, all the pressurized oil from the PPC valve flows through port A, spool (2), and port B to the control valve. At this time, port T is closed and any oil does not flow in the tank.
PC78MR-6
When signal current is reduced (When coil is energized and circuit pressure is low) • If the signal current flowing from the controller into coil (1) is reduced, coil (1) is still energized but its thrust is lowered in proportion to the signal current. • As a result, push pin (3) pushes down spool (2) and the pressurized oil from port A flows to port B. • If the pressure in port B rises and the force applied to face "a" of spool (2) becomes larger than the thrust of coil (1), spool (2) is pushed up and port A is disconnected from port B and connected to port T. • Accordingly, spool (2) moves up and down so that the thrust of coil (1) will be balanced with the pressure in port B. • As a result, the circuit pressure between the PPC valve and control valve is controlled in proportion to the signal current.
10-37
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SOLENOID VALVE
When signal current is 0 (When coil is de-energized and circuit cut out) • If the signal current flowing from the controller into coil (1) becomes 0, coil (1) is deenergized. • As a result, spool (2) is pressed up by return spring (4). • Accordingly, port A is closed and the pressurized oil from the PPC valve does not flow into the control valve. At this time, the oil from the control valve is drained through ports B and T into the tank.
Signal current is 0 o increased o maximum • The valve operates in the order of 3, 2, and 1 explained above.
10-38
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SOLENOID VALVE
Control relief valve •
If the pressure of the hydraulic oil from the control pump rises, the oil in port A pushes spool (1). The reaction force of spool (1) compresses spring (2) and moves spool (1) to the right to open ports A and T to relieve the circuit. Set pressure: 3.1 MPa {32 kg/cm²}
PC78MR-6
10-39
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
MULTI-CONTROL VALVE
MULTI-CONTROL VALVE (OPTIONAL)
(1) JIS Pattern (2) Backhoe Pattern * Operation pattern selection drawing (Port names correspond to symbols in drawing)
10-40
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ACCUMULATOR FOR BRAKE
ACCUMULATOR FOR BRAKE (If equipped)
1. 2. 3. 4. 5. 6.
Cap Core Guard rubber Lid Plug Shell
PC78MR-6
Specification Type of gas
Nitrogen Gas
Gas volume ( )
0.48
Sealed gas pressure
–
(MPa {kg/cm²})
0.1 {1} (at 80 °C)
Max. actuating pressure
–
(MPa {kg/cm²})
6.86 {70}
10-41 (1)
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
HYDRAULIC PUMP
HYDRAULIC PUMP Model: LPD45 + 45
P1 P2 P4 PD PM P1T P2T
: Pump discharge : Pump discharge : Pilot pump discharge : Drain : PC mode changeover pressure pickup port : Travel deviation adjustment orifice : Travel deviation adjustment orifice
10-42
PD2 : Pump drain (plug) PDA : Air bleeder PEN : Control pressure pickup port PLS : LS pressure input (From control valve) PPT : PTO oil filler PS1 : Main pump suction PEPC : EPC main pressure pickup port PPLS : Pump pressure input (From control valve)
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
T P1 P2 P3 P5 PD PH
: : : : : : :
Drain Pump discharge Pump discharge Gear pump pressure input Gear pump pressure pickup port Drain Pump shuttle
PC78MR-6
HYDRAULIC PUMP
PAV PD2 PDE PEN PPT PS1 PEPC
: : : : : : :
Pump average pressure Drain (Plug) EPC drain Control pressure input PTO oil filler Pump suction EPC main pressure pickup port
10-43
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
HYDRAULIC PUMP
Shaft Flange Case Rocker cam Shoe Piston Cylinder block Valve plate Servo piston Oil seal
10-44
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
HYDRAULIC PUMP
With blade Model: LPD45 + 45
P1 P2 P3 P4 P5 PD PM P1T P2T
: Pump discharge : Pump discharge : Gear pump discharge : Pilot pump discharge : Gear pump pressure pickup port : Drain : PC mode changeover pressure pickup port : Travel deviation adjustment orifice : Travel deviation adjustment orifice
PC78MR-6
PD2 : Pump drain (plug) PDA : Air bleeder PEN : Control pressure pickup port PGS : Gear pump suction PLS : LS pressure input (From control valve) PPT : PTO oil filler PS1 : Main pump suction PEPC :EPC main pressure pickup port PPLS :Pump pressure input (From control valve)
10-45
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
T P1 P2 PD PH PAV PD2
: Drain :Pump discharge : Pump discharge :Drain :Pump shuttle :Pump average pressure :Drain (Plug)
10-46
HYDRAULIC PUMP
PD3 :Drain PDE :EPC drain PEN :Control pressure input PPT :PTO oil filler PS1 :Pump suction PEPC :EPC main pressure pickup port
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
HYDRAULIC PUMP
Shaft Flange Case Rocker cam Shoe Piston Cylinder block Valve plate Servo piston Oil seal
PC78MR-6
10-47
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
HYDRAULIC PUMP
PDE: EPC drain 1. EPC valve PC valve T: Drain P3: Gear pump pressure input PH: Pump shuttle pressure PAV: Pump average pressure PPL: PC valve output pressure PEPCOUT: EPC output pressure 2. Lever 3. Spring
10-48
4. Retainer 5. Seat 6. Spool 7. Sleeve 8. Piston 9. Seal 10. Piston 11. Plug
LS valve PE: Control piston pressure PH: Pump shuttle pressure PLS: LS pressure input PPL: PC valve output pressure PPLS: LS pump pressure input 12. Spool 13. Plug
14. Seat 15. Spring 16. Seat 17. O-ring 18. Backup ring 19. Nut 20. Plug
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
Function • This pump converts the revolution and torque of the engine transmitted to its shaft into hydraulic energy and discharges hydraulic oil according to the load. • The discharge can be changed by changing the swash plate angle.
HYDRAULIC PUMP
•
The oil in each cylinder of cylinder block (7) can be drawn and discharged through valve plate (8).
Structure • Cylinder block (7) is supported on shaft (1) through spline a. Shaft (1) is supported on the front and rear bearings. • The end of piston (6) is a concave sphere, which holds shoe (5) as a spherical bearing. • Rocker cam (4) has plane A. Shoe (5) is kept pressed against plane A and slid circularly. Rocker cam (4) is supported on flange (2) and ball (12) fixed to the case and slides on the formed static pressure bearing and high-pressure oil. • Piston (6) moves axially and relatively in each cylinder of cylinder block (7). • Cylinder block (7) revolves relatively against valve plate (8), sealing the hydraulic oil. The hydraulic pressure on the revolving surface of the cylinder block is balanced properly.
PC78MR-6
10-49
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
HYDRAULIC PUMP
Operation 1. Operation of pump •
Shaft (1) and cylinder block (7) revolve together and shoe (5) slides on plane A. As rocker cam (4) slants around ball (12) at this time, angle ( ) between the center line X of rocker cam (4) and axis of cylinder block (7) changes. Angle ( ) is called the swash plate angle.
•
• •
• •
•
If center line X of rocker cam (4) is in the direction of the axis of cylinder block (7) (Swash plate angle = 0), the difference between volumes E and F in cylinder block (7) is 0 and oil is not sucked or discharged (The swash plate angle is not reduced to 0 actually, however). In short, swash plate angle ( ) is in proportion to the discharge of the pump. The number of holes on cylinder block (7) is even 10 and every second one of them is fitted to 2 grooves of valve plate (8). The quantity of the oil equivalent to 5 pistons is discharged to each of P1 and P2.
If the angle between the center line X of rocker cam (4) and the axis of cylinder block (7) is a, plane A works as a cam for shoe (5). Accordingly, piston (6) slides inside cylinder block (7) and makes difference between volumes E and F in cylinder block (7) and the oil is drawn and discharged by the difference. In short, if cylinder block (7) revolves and volume of chamber E is reduced, the oil is discharged. On the other hand, the volume of chamber F is increased and the oil is sucked. (The figure shows the end of suction process of chamber F and the end of discharge process of chamber E.)
10-50
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
HYDRAULIC PUMP
2. Control of discharge
LS valve
•
Function • The LS valve controls the discharge of the pump according to the stroke of the control lever, or the demand flow for the actuator. • The LS valve calculates the demand flow for the actuator from differential pressure EPLS between inlet pressure PPLS and outlet pressure PLS of the control valve, and controls discharge Q of the main pump. (PPLS is called the LS pump pressure, EPLS the LS pressure, and EPLS the LS differential pressure.) • That is, the discharge of the pump is controlled according to the demand flow for the actuator by the following method; The pressure loss made when the oil flows through the opening of the control valve spool (LS differential pressure EPLS) is sensed and discharge Q of the pump is so controlled that the pressure loss will be constant. • The LS valve receives main pump discharge pressure PP, LS pump pressure (PPLS), and LS pressure PLS. The relationship between the LS differential pressure (EPLS) and pump discharge Q changes as shown below.
•
If swash plate angle ( ) is increased, the difference between volumes E and F, or discharge Q, is increased. Swash plate angle ( ) is changed with servo piston (11). Servo piston (11) is reciprocated linearly by the signal pressure of PC and LS valves. This linear motion is transmitted to rocker cam (4) supported on flange (2) through ball (12). Then, rocker cam (4) slides in the revolutionary direction.
PC78MR-6
10-51
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
PC valve Function • The PC valve limits the oil flow to a certain level (according to the discharge pressure) even if the stroke of the control valve is increased so that the horsepower absorbed by the pump will not exceed the engine horsepower, as long as pump discharge pressure PP is high. That is, the PC valve performs constant-horsepower control. • In other words, the PC valve decreases the pump discharge when the load is increased and the pump discharge pressure rises and increases it when the pump discharge pressure lowers. • This pump has 2 discharge openings and the average of discharge pressures P1 and P2 at those openings is sensed. The average of P1 and P2 is called the PAVE. The relationship between this average and pump discharge (discharge from the 2 discharge openings) is shown below.
Operation 1. With blade (1) Function of spring • The spring load of spring (2) at the PC valve is decided by the position of the swash plate. • If servo piston (6) moves to the right, spring (2) is compressed through lever (1) and its spring load changes. The spring constant of this spring changes to 2 levels. (2) When pump pressure PAVE is low • The pressure of spool (4) is decreased and spool (3) is a little to the right (Fig. 1 and Fig. 4). At this time, ports C and D are connected to each other and the pressure in the LS valve is drain pressure PT.
10-52
HYDRAULIC PUMP
•
• •
•
At this time, ports F and G of the LS valve are connected to each other. As a result, the pressure in port J becomes drain pressure PT and servo piston (6) moves to the left. Consequently, the pump discharge is increased. As servo piston (6) moves, lever (1) moves to the left and spring (2) expands and its spring load is decreased. Consequently, spool (3) moves to the left to break the connection of ports C and D, and then pump discharge ports B and C are connected. As a result, the pressure in port C rises and the piston pressure is increased and servo piston (6) stops moving to the left.
(3) When pump pressure PAVE is high • The pressure of spool (4) is increased and spool (3) is a little to the left (Fig. 2 and Fig. 5). At this time, ports C and B are connected to each other and the pressure in the LS valve is pump pressure PP. • At this time, ports F and G of the LS valve are connected to each other. As a result, the pressure in port J becomes pump pressure PP and servo piston (6) moves to the right. • Consequently, the pump discharge is decreased. • As servo piston (6) moves, lever (1) moves to the right and spring (2) is compressed and its spring load is increased. Consequently, spool (3) moves to the right to break the connection of ports C and B, and then drain pressure ports D and C are connected. • As a result, the pressure in port C lowers and the piston pressure is decreased and servo piston (6) stops moving to the right. • Accordingly, the stopping position (= pump discharge) of servo piston (6) is decided by the position where the pressure caused by pressure PP applied to spool (4) is balanced with the force of spring (2) applied through spool (3) (Fig. 3 and Fig. 6). (4) When swing gear pump pressure rises/lowers • The pressure of spool (4) changes and the pump discharge changes similarly to the case where the PAVE rises/lowers. • The PC-EPC valve changes the output pressure according to the input current from the controller, then the pressure of spool (5) changes and the pump discharge changes similarly to the case where the PAVE rises/lowers.
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
HYDRAULIC PUMP
When load is light
When load is heavy
PC78MR-6
10-53
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
HYDRAULIC PUMP
When balanced
2. Without blade • Although the swing gear pump is not mounted, the theory of operation of this model is the same as that of the machine equipped with the swing gear pump. When load is light
10-54
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
HYDRAULIC PUMP
When load is heavy
When balanced
PC78MR-6
10-55
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CONTROL VALVE
CONTROL VALVE Outline (1) Outside view A1: To blade cylinder head A2: To swing motor A3: To left travel motor A4: To right travel motor A5: To boom swing cylinder head A6: To boom cylinder bottom A7: To arm cylinder head A8: To bucket cylinder head A9: To attachment B1: To blade cylinder bottom B2: To swing motor B3: To left travel motor B4: To right travel motor B5: To boom swing cylinder bottom B6: To boom cylinder head B7: To arm cylinder bottom B8: To bucket cylinder bottom B9: To attachment BP: From boom RAISE PPC valve LS: To pump LS valve (LS pressure input) P1: From main pump P2: From main pump P3: From gear pump PP: To pump LS valve (Pump pressure input) PT: To travel pressure switch TB: To tank TC: To oil cooler TS: To tank PA1: From blade raise PPC valve PA2: From swing right PPC valve PA3: From left travel reverse PPC valve PA4: From right travel reverse PPC valve PA5: From boom swing right PPC valve PA6: From boom raise PPC valve PA7: From arm out PPC valve PA8: From bucket dump PPC valve PA9: From attachment PPC valve PB1: From blade lower PPC valve PB2: From swing left PPC valve PB3: From left travel forward PPC valve PB4: From right travel forward PPC valve PB5: From boom swing left PPC valve PB6: From boom lower PPC valve PB7: From arm in PPC valve PB8: From bucket curl PPC valve PB9: From attachment PPC valve TSW: To swing motor
10-56
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
PC78MR-6
CONTROL VALVE
10-57
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CONTROL VALVE
(2) Sectional view
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17.
Safety-suction valve (Blade head) Suction valve (Left travel) Suction valve (Right travel) Suction valve (Boom swing head) Suction valve (Boom bottom) Suction valve (Arm head) Suction valve (Bucket head) Suction valve (Attachment) Suction valve (Attachment) Suction valve (Bucket bottom) Suction valve (Arm bottom) Suction valve (Boom head) Suction valve (Boom swing bottom) Suction valve (Right travel) Suction valve (Left travel) Suction valve (Blade bottom) Main relief valve
10-58
18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28. 29. 30. 31 32. 33. 34.
Gear pump relief valve Safety valve Cooler bypass valve Spool (Boom raise merge) Spool (Blade) Spool (Swing) Spool (Left travel) Spool (Right travel) Spool (Boom swing) Spool (Boom) Spool (Arm) Spool (Bucket) Spool (Attachment) Unload valve (P1) Unload valve (P2) LS pressure pickup plug (LS1) LS pressure pickup plug (LS2)
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CONTROL VALVE
Unit: mm No.
Item
Criteria Basic dimensions
35
Cooler bypass valve spring
Remedy Allowable limit
Free length x Outside diameter
Installed length
Installed load
Free length
Installed load
34.5 X 17.7
25
73.5 N {7.5 kg}
—
58.8 N {6.0 kg}
36
Spool return spring (Work equipment)
41.1 X 19.3
40.5
34.3 N {3.5 kg}
—
27.4 N {2.8 kg}
37
Spool return spring (Arm out)
42.3 X 19.2
38.9
103.9 N {10.6 kg}
—
83.2 N {8.48 kg}
38
Spool return spring (Trave)
29.0 X 17.5
25.0
180.5 N {18.02 kg}
—
14.5 N {14.74 kg}
39
Unload valve spring
40.9 X 15.1
33.5
129 N {13.2 kg}
—
103 N {10.6 kg}
40
Boom RAISE merge valve spring
42.4 X 19.0
13
287.3 N {29.3 kg}
—
230 N {23.44 kg}
41
Spool return spring (Blade)
29.01 X 18.3
27.5
89.5 N {9.1 kg}
—
71.6 N {7.28 kg}
42
Spool return spring (Boom raise)
41.13 X 19.3
38.5
136.4 N {13.91 kg}
—
109 N {11.13 kg}
43
Spool return spring (Bucket curl, Boom lower)
41.47 X 19.3
38.5
135.53 N {13.82 kg}
—
108 N {11.06 kg}
44
Spool return spring (Boom swing)
29.20 X 17.5
25.0
162.54 N {16.57 kg}
—
130 N {13.26 kg}
45
Spool return spring (Swing)
29.03 X 18.4
26.0
173.2 N {17.66 kg}
—
139 N {14.13 kg}
PC78MR-6
If damaged or deformed, replace spring.
10-59
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15.
Spool (Pump merge-divider valve) Pressure compensation valve F (Left travel) Pressure compensation valve F (Right travel) Pressure compensation valve F (Boom swing) Pressure compensation valve F (Boom) Pressure compensation valve F (Arm) Pressure compensation valve F (Bucket) Pressure compensation valve F (Attachment) Pressure compensation valve R (Attachment) Pressure compensation valve R (Bucket) Pressure compensation valve R (Arm) Pressure compensation valve R (Boom) Pressure compensation valve R (Boom swing) Pressure compensation valve R (Right travel) Pressure compensation valve R (Left travel)
10-60
CONTROL VALVE
16. 17. 18. 19. 20. 21. 22. 23. 24. 25. 26. 27. 28.
Pump pressure pickup plug (P2) LS pressure pickup plug (LS3) LS bypass plug (LS2) LS bleed valve Travel junction valve, LS bleed valve Logic valve Boom hydraulic drift prevention valve Check valve (Blade) Check valve (Swing) Check valve (Boom bottom) Check valve (Arm) Check valve (Bucket) Check valve (Attachment)
F: Flow control valve R: Pressure reducing valve
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CONTROL VALVE
Unit: mm No.
Item
Criteria Basic dimensions
29
Free length x Pressure compensation Outside diamvalve spring eter
Remedy Allowable limit
Installed length
Installed load
Free length
Installed load
28.0 X 14.4
14.5
13.7 N {1.4 kg}
—
11.0 N {1.12 kg}
30
Pressure compensation valve spring
33.4 X 14.4
21.5
55.9 N {5.7 kg}
—
44.7 N {4.56 kg}
31
Pressure compensation valve spring
30.9 X 5.2
27
9.8 N {1.0 kg}
—
7.85 N {0.8 kg}
32
Pressure compensation valve spring
20.0 X 8.4
12
6.86 N {0.7 kg}
—
5.49 N {0.56 kg}
33
Pump merge-divider valve spool return spring
33.2 X 14.2
22.5
49.0 N {5.0 kg}
—
39.2 N {4.0 kg}
34
Check valve spring
27.2 X 6.9
22
3.92 N {0.4 kg}
—
3.14 N {0.32 kg}
35
Check valve spring
12.3 X 11.4
10.5
3.92 N {0.4 kg}
—
3.14 N {0.32 kg}
36
Check valve spring
21.9 X 5.0
15.8
1.96 N {0.2 kg}
—
1.57 N {0.16 kg}
37
Check valve spring
13.0 X 6.5
9.5
1.96 N {0.2 kg}
—
1.57 N {0.16 kg}
38
Pressure compensation valve spring
28.0 X 14.4
14.5
13.72 N {1.4 kg}
—
11.0 N {1.12 kg}
PC78MR-6
If damaged or deformed, replace spring.
10-61
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
10-62
CONTROL VALVE
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CONTROL VALVE
Unit: mm No.
Item
Criteria Basic dimensions
1
2
Check valve spring
Travel junction valve spring
PC78MR-6
Remedy Allowable limit
Free length x Outside diameter
Installed length
Installed load
Free length
Installed load
21.9 X 5.0
15.8
1.96 N {0.2 kg}
—
1.57 N {0.16 kg}
19.3 X 7.5
14
15.7 N {1.6 kg}
—
12.6 N {1.28 kg}
If damaged or deformed, replace spring.
10-63
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
10-64
CONTROL VALVE
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
1. 2. 3. 4.
CONTROL VALVE
Pump pressure pickup plug (P1) LS bypass plug (LS1) Check valve (P1) Check valve (P2)
Unit: mm No.
Item
Criteria Basic dimensions
5
Check valve spring
Remedy Allowable limit
Free length x Outside diameter
Installed length
Installed load
Free length
Installed load
13.0 X 6.5
9.5
1.96 N {0.2 kg}
—
1.57 N {0.16 kg}
6
Hydraulic drift prevention valve spring
16.6 X 13.0
13
11.2 N {1.14 kg}
—
8.96 N {0.91 kg}
7
Hydraulic drift prevention valve spring
13.0 X 8.8
7.5
10.8 N {1.1 kg}
—
8.64 N {0.88 kg}
PC78MR-6
If damaged or deformed, replace spring.
10-65
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
10-66
CONTROL VALVE
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CONTROL VALVE
1. Pump pressure pickup plug (P2) 2. Check valve (Boom head) 3. Pressure release plug Unit: mm No.
Item
Criteria Basic dimensions
4
Logic valve spring
PC78MR-6
Remedy Allowable limit
Free length x Outside diameter
Installed length
Installed load
Free length
Installed load
11.0 X 6.2
9.5
5.5 N {0.56 kg}
—
4.4 N {0.45 kg}
If damaged or deformed, replace spring.
10-67
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
CLSS OUTLINE OF CLSS Features CLSS stands for Closed center Load Sensing System, and has the following featues. • Fine control not influenced by load • Control enabling digging even with fine control • Ease of compound operation ensured by flow divider function using area of opening of spoll during compund operations • Energy saving using variable pump control
10-68
Structure • The CLSS consists of a variable capacity single piston pump, control valve, and actuators. • The pump body consists of the main pump, PC valve and LS valve.
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
BASIC PRINCIPLE 1. Control of pump swash plate angle • The pump swash plate angle (pump discharge amount) is controlled so that LS differential pressure EPLS (the difference between pump (discharge) pressure PP and control valve outlet port LS pressure PLS) load pressure of actuator) is constant. (LS pressure EPLS=Pump discharge pressure PP-LS pressure PLS)
If LS differential pressure EPLS becomes lower than the set pressure of the LS valve (when the actuator load pressure is high), the pump swash plate moves towards the maximum position; if the set pressure becomes higher than the set pressure of the LS valve (when the actuator load pressure is low), the pump swash plate moves towards the minimum position. a For details of the operation, see HYDRAULIC PUMP.
•
PC78MR-6
10-69
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
2. Pressure compensation control • A pressure compensation valve is installed to the inlet port side of the control valve spool to balance the load. When to actuators are operated together, this valve acts to make pressure difference EP between the upstream (inlet port) and down-
10-70
CLSS
stream (outlet port) the same, regardless of the size of the load (pressure). In this way, the flow of oil from the pump is divided (compensated) in proportion to the area of openings S1 and S2 of each valve when it is operated.
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
OPERATION FOR EACH FUNCTION AND VALVE Hydraulic circuit diagram and name of valves
10-72
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
1. Unload valve (P1) Set pressure: LS pressure + 2.45 MPa {25 kg/cm2} 2. Unload valve (P2) Set pressure: LS pressure + 2.45 MPa {25 kg/cm2} 3. Main relief valve Set pressure: 26.5 MPa {270 kg/cm2} 4. Gear pump relief valve Set pressure: 21.1 MPa {215 kg/cm2} 5. Cooler bypass valve 6. Suction valve 7. Safety-suction valve Set pressure: 9.8 MPa {100 kg/cm2} 8. Safety valve Set pressure: 27.9 MPa {285 kg/cm2} 9. Pressure compensation valve 10. LS bypass plug (P1) 11. LS bypass plug (P2) 12. Boom raise merge valve 13. LS bleed valve 14. Travel junction valve, LS bleed valve 15. Logic valve 16. Boom hydraulic drift prevention valve
PC78MR-6
10-73
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
Unload valve 1. When control valve is at HOLD
Function • When the control valve is at HOLD, pump discharge amount Q discharged by the minimum swash plate angle is released to the tank circuit. At this time, pump discharge pressure PP1/PP2 is set at 2.45 MPa {25.0 kg/cm2} by spring (2) in the valve. (LS pressure PLS1/PLS2: 0 MPa {0 kg/cm2}) • Since the pump merge-divider valve is at the merge position, pump discharge pressures PP1 and PP2 are merged. LS pressures PLS1, PLS2, and PLS3 are also merged.
•
•
•
When the control valve is at HOLD, LS pressures PLS1 and PLS2 are not generated, so only pump discharge pressures PP1 and PP2 act, and PP1 and PP2 are set by only the load of spring (2). As pump discharge pressure PP1/PP2 rises and reaches the load of spring (2) (2.45 MPa {25.0 kg/cm2}), spool (1) is moved to the right. Pump discharge pressures PP1 and PP2 are connected to tank circuit T through the cut of spool (1) As a result, pump discharge pressure PP1/PP2 is set to 2.45 MPa {25.0 kg/cm2}.
Operation • Pump discharge pressures PP1 and PP2 are acting on the left end of unload spool (1) and LS pressures PLS1 and PLS2 are acting on the right end. (PP1 = PP2, PLS1 = PLS2)
10-74
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
2. During fine control of work equipment valve Work equipment valve: Boom, arm, bucket, boom swing, or attachment.
Function • During fine control of the work equipment valve, when the demand flow for the actuator is within the amount discharged by the minimum swash plate angle of the pump, pump discharge pressure PP1/PP2 is set to LS pressure PLS1/PLS2 + 2.45 MPa {25.0 kg/cm2}. When the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 reaches the load of spring (2) (2.45 MPa {25.0 kg/cm 2 }), unload spool (1) opens, so LS differential pressure EPLS becomes 2.45 MPa {25 kg/cm2}. • Since the pump merge-divider valve is at the merge position, pump discharge pressures PP1 and PP2 are merged. LS pressures PLS1, PLS2, and PLS3 are also merged.
PC78MR-6
Operation • When fine control is carried out on the work equipment valve, LS pressures PLS1 and PLS2 are generated and act on the right end of spool (1) (PP1 = PP2, PLS1 = PLS2). When this happens, the area of the opening of the work equipment valve spool is small, so LS pressures PLS1 and PLS2 are very different from pump discharge pressures PP1 and PP2. • When the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 reaches the load of spring (2) (2.45 MPa {25.0 kg/cm2}), spool (1) moves to the right, and pump discharge pressures PP1 and PP2 are connected to tank circuit T. • In other words, pump discharge pressure PP1/ PP2 is set to the spring force (2.45 MPa {25.0 kg/cm2}) + LS pressure PLS1/PLS2, and LS differential pressure DPLS becomes 2.45 MPa {25.0 kg/cm2}.
10-75
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
3. When work equipment valve is operated Work equipment valve: Boom, arm, bucket, boom swing, or attachment
Function • When any work equipment valve is operated if the demand flow for the actuator becomes greater than the pump discharge from the minimum swash plate angle, the oil flow to tank circuit T is cut off, and all pump discharge amount Q flows to the actuator circuit. • Since the pump merge-divider valve is at the merge position, pump discharge pressures PP1 and PP2 are merged. LS pressures PLS1, PLS2, and PLS3 are also merged.
Operation • When any work equipment valve is operated for a long stroke, LS pressures PLS1 and PLS2 are generated and act on the right end of unload spool (1) (PP1 = PP2, PLS1 = PLS2). When this happens, the area of the opening of the work equipment valve spool is large, so LS pressures PLS1 and PLS2 are not so different from pump discharge pressures PP1 and PP2. •
•
10-76
For this reason, the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 does not reach the load of spring (2) (2.45 MPa {25.0 kg/cm2}), so spool (1) is pushed to the left by spring (2). As a result, pump discharge pressures PP1 and PP2 and tank circuit T are shut off, and all pump discharge amount Q flows to the actuator circuit.
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
4. During fine control of both travel valves
Function • During fine control of both travel valves, when the demand flow is below the maximum pump discharge amount, pump discharge pressure PP1/PP2 is set to LS pressure PLS1/PLS2 + 2.45 MPa {25.0 kg/cm2}. • When the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 reaches the load of spring (2) (2.45 MPa {25.0 kg/cm2}), unload spool (1) opens, so excessive oil (maximum pump discharge mount - demand flow) flows into the tank circuit. • Since the pump merge-divider valve is at the separate position, pump discharge pressures PP1 and PP2 are separated. LS pressures PLS1 and PLS2 are also separated. • The swash plate angle of the pump becomes maximum, so the pump discharge amount becomes maximum. (For details, see the sections on the pump merge-divider valve and logic valve.)
PC78MR-6
Operation • When fine control is carried out on both travel valves, LS pressures PLS1 and PLS2 are generated and act on the right end of spool (1) (PP1, PP2, PLS1, and PLS2 are separated). • When this happens, the area of the opening of both travel valve spools is small, so LS pressures PLS1 and PLS2 are very different from pump discharge pressures PP1 and PP2. • When the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 reaches the load of spring (2) (2.45 MPa {25.0 kg/cm2}), spool (1) moves to the right, and pump discharge pressures PP1 and PP2 are connected to tank circuit T and the excessive oil (maximum pump discharge mount – demand flow) flows. • In other words, the excessive oil (maximum pump discharge mount – demand flow) above the strokes of both travel valves flows into tank circuit T.
10-77
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
5. When both travel valves are operated
Function • During operation of both travel valves, when the demand flow becomes maximum, the oil flow to tank circuit T is cut off, and all pump discharge amount Q flows to both travel circuits. • Since the pump merge-divider valve is at the separate position, pump discharge pressures PP1 and PP2 are separated. LS pressures PLS1 and PLS2 are also separated. • The swash plate angle of the pump becomes maximum, so the pump discharge amount becomes maximum. (For details, see the sections on the pump merge-divider valve and logic valve.)
10-78
Operation • When both travel valves are operated to the stroke ends, LS pressures PLS1 and PLS2 are generated and act on the right end of unload spool (1) (PP1, PP2, PLS1, and PLS2 are separated). • When this happens, the area of the openings of both travel valve spools is large, so LS pressures PLS1 and PLS2 are not so different from pump discharge pressures PP1 and PP2. • For this reason, the difference between pump discharge pressure PP1/PP2 and LS pressure PLS1/PLS2 does not reach the load of spring (2) (2.45 MPa {25.0 kg/cm2}), so spool (1) is pushed to the left by spring (2). • As a result, pump discharge pressures PP1 and PP2 and tank circuit T are shut off, and all pump discharge amount Q flows to the actuator circuit.
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
6. When either travel valve is operated
Function • The demand flow decided by the valve stroke is sent to the travel circuit on the operated travel valve side and the all pump discharge amount is sent to the tank circuit on the non-operated travel valve side. • Since the pump merge-divider valve is at the separate position, pump discharge pressures PP1 and PP2 are separated. LS pressures PLS1 and PLS2 are also separated. • The swash plate angle of the pump becomes maximum, so the pump discharge amount becomes maximum. (For details, see the sections on the pump merge-divider valve and logic valve.)
•
Operation When left travel valve is operated to stroke end and right one is at HOLD. • When the left travel valve is operated to the stroke end, LS pressure PLS1 is generated and acts on the right end of unload spool (1).
•
PC78MR-6
•
•
•
When this happens, the area of the openings of both travel valve spools is large, so LS pressures PLS1 is not so different from pump discharge pressures PP1. For this reason, the difference between pump discharge pressure PP1 and LS pressure PLS1 does not reach the load of spring (2) (2.45 MPa {25.0 kg/cm2}), so spool (1) is pushed to the left by spring (2). As a result, pump discharge pressures PP1 and tank circuit T are shut off, and all pump discharge amount QP1 on the P1 side flows to the left travel circuit. Since the right travel valve is at HOLD, LS pressure PLS2 is not generated, so only pump discharge pressure PP2 acts. When pump discharge pressure PP2 reaches the load of spring (4) (2.45 MPa {25.0 kg cm2}), spool (3) moves to the right, and all pump discharge amount QP2 on the P2 side flows into tank circuit T.
10-79
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
Pump merge-divider valve and logic valve 1. When control valve is at HOLD
Function • Pump merge-divider valve spool (3) merges pump discharge pressures PP1 and PP2 and LS pressures PLS1, PLS2, and PLS3 respectively. Operation • When the control valve is at HOLD, changeover pressure is not generated on logic spool (1), so spring (2) pushes spool (1) to the left. • Since both travel valves are at HOLD, changeover pressure is not generated on the pump merge-divider spool. • When the control valve is at HOLD, changeover pressure is not generated on the pump mergedivider spool, so spring (4) pushes spool (3) to the right. • Pump discharge pressures PP1 and PP2 and LS pressures PLS1, PLS2, and PLS3 are merged respectively (PP1 = PP2, PLS1 = PLS2 = PLS3).
10-80
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
2. When work equipment valve is operated (including compound operation of work equipment + travel). Work equipment valve: Boom, arm, bucket, boom swing, or attachment.
Function • Pump merge-divider valve spool (3) merges pump discharge pressures PP1 and PP2 and LS pressures PLS1, PLS2, and PLS3 respectively. • As the LS pressure, PLS1, PLS2, and PLS3 are output.
• •
When the work equipment valve is operated, changeover pressure for spool (3) is not generated, so spring (4) pushes spool (3) to the right. Pump discharge pressures PP1 and PP2 are merged. LS pressures PLS1, PLS2, and PLS3 are also merged (PP1 = PP2, PLS1 = PLS2 = PLS3).
Operation • When any work equipment valve is operated, the work equipment PPC pressure or the swing holding brake release pressure is introduced in the left chamber of logic spool (1) to change over spool (1). • When the load of spring (2) reaches 0.6 MPa {6 kg/cm2}, spool (1) moves to the right. • As a result, the right chamber of spool (3) is connected to tank circuit T and changeover pressure for spool (3) is not generated.
PC78MR-6
10-81
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
3. When either or both travel valves are operated
Function • Pump merge-divider valve spool (3) separates pump discharge pressures PP1 and PP2 and LS pressures PLS1, PLS2, and PLS3 respectively. • As the LS pressure, higher pressure of PP1 and PP2 is output. Operation • Since the all work equipment valves are at HOLD, changeover pressure for logic spool (1) is not generated, spring (2) pushes spool (1) to the left. • When both travel valves are operated, travel PPC pressure is introduced as changeover pressure for spool (3) through spool (1) into the right chamber of spool (3). • When the load of spring (4) reaches 0.49 MPa {5 kg/cm2}, spool (3) is pushed to the left. • As a result, pump discharge pressures PP1 and PP2 and LS pressures PLS1 and PLS2 are separated respectively.
10-82
• •
Furthermore, PP1 and PLS1 are separated for the left travel circuit and PP2 and PLS2 are separated for the right travel circuit. The higher pressure of pump discharge pressures PP1 and PP2 is output as the LS pressure and the swash plate angle of the pump becomes maximum, so the pump discharge amount becomes maximum.
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
Introduction of LS pressure 1. Work equipment valve: Boom, arm, bucket, boom swing, or attachment
Function • The LS pressure is the actuator load pressure at the outlet port end of the control valve. • Actually, pump discharge pressure PP is reduced by reducing valve (3) of the pressure compensation valve to the same pressure as actuator circuit pressure A and sent to LS circuit PLS. • In the travel valve, actuator circuit pressure A is directly introduced to LS circuit PLS. Operation • When spool (1) is operated, pump discharge pressure PP flows from flow control valve (2) through notch (a) in the spool and bridge passage (b) to actuator circuit A. • At the same time, reducing valve (3) also moves to the right, so pump discharge pressure PP is reduced by the pressure loss at notch (c). It goes to LS circuit PLS, and then goes to spring chamber PLSS.
PC78MR-6
• •
•
When this happens, LS circuit PLS is connected to tank circuit T from LS bypass plug (4) (See the section on the LS bypass plug). The areas at both ends of reducing valve (3) are the same (SA = SLS), and actuator circuit pressure PA acts on the SA end. The reduced pump discharge pressure PP acts on SLS at the other end. As a result, reducing valve (3) is balanced at a position where actuator circuit pressure PA and the pressure of spring chamber PLSS are the same. Pump discharge pressure PP reduced at notch (c) becomes actuator pressure A and is introduced into LS circuit PLS.
10-83
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
2. Travel valve
Operation • When spool (1) is operated, pump discharge pressure PP flows from flow control valve (2) through notch (a) in the spool and bridge passage (b) to actuator circuit A. • At the same time, reducing valve (3) is moved to the right by actuator circuit pressure PA, and notch (c) and notch (d) are interconnected respectively with travel junction circuit (e) and LS circuit PLS. • As a result, actuator circuit pressure PA (= A) is introduced from notch (c) through the internal check valve and notch (d) into LS circuit PLS. a The travel circuit is different from the work equipment circuit: actuator circuit pressure PA is directly introduced into LS circuit PLS.
10-84
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
LS bypass plug When work equipment valve is operated
When both travel valves are operated
Function • The LS bypass plug releases the residual pressure of LS pressure PLS. • This lowers the rising speed of LS pressure PLS. In addition, the discarded throttled flow causes a pressure loss in the throttled flow in the reducing valve, and that lowers the effective LS differential pressure to improve the stability. Operation 1. When work equipment valve is operated (including compound operation of work equipment + travel) • Since pump merge-divider spool (1) is at the merge position, the hydraulic oil in LS circuits PLS1, PLS2, and PLS3 flows from tip filter
PC78MR-6
(a) of LS bypass plug (2) through orifice (b) to tank circuit T. 2. When either or both travel valves are operated • Since pump merge-divider spool (1) is at the separate position, LS circuits PLS1, PLS2, and PLS3 are separated. • The hydraulic oil PLS1 flows from tip filter (a) of LS bypass plug (3) on the P1 side through orifice (b) to tank circuit T. • The hydraulic oil PLS2 flows from tip filter (a) of LS bypass plug (2) on the P2 side through orifice (b) to tank circuit T.
10-85
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
Boom raise merge valve During normal operation
When machine swings and boom is raised simultaneously
Function • When the machine swings and the boom is raised simultaneously, this valve merges discharge amount of the gear pump into that of main pump to heighten the boom raising speed. Operation 1. During normal operation • When the boom is not raised, the pilot pressure is not applied to pilot port BP. • Under this condition, gear pump circuit P3 and main pump circuit PP are shut off by spool (1), so oil in gear circuit P3 is not merged into that of main pump circuit PP.
10-86
2. When machine swings and boom is raised simultaneously • When the machine swings and boom is raised simultaneously, the signal pressure of the boom RAISE PPC circuit is applied to pilot port BP. • When pilot pressure BP acts on spool (1) and increases above the force of spring (2), spool is pushed to the right. Then, check valve (3) in spool (1) is pushed open and oil in gear pump circuit P3 is merged into that in main pump circuit PP to heighten the boom raising speed.
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
Area ratio of pressure compensation valve
Function • The pressure compensation valve determines the compensation characteristics by carrying out fine adjustment of the area r atio ( S2/S1) between (left) area S1 of flow control valve (2) and (right) area S2 of reducing valve (1) to match the characteristics of each actuator. S1: Area of flow control valve (2) – area of piston (3) S2: Area of reducing valve (1) – area of piston (3)
PC78MR-6
Area ratio (S1:S2) and compensation characteristics • When ratio is 1.00: [Pump discharge pressure PP - spool notch upstream pressure PPB] = [LS circuit pressure PLS - actuator circuit pressure PA (= A)] and oil flow is divided in proportion to area of opening of spool. • When ratio is more than 1.00:PP – PPB > PLS – PA ( = A ) a nd oi l fl o w i s divided in a proportion less tha n ar ea of ope ning of spool. • When ratio is less than 1.00:PP – PPB < PLS – PA ( = A ) a nd oi l fl o w i s divided in a proportion more tha n ar ea of ope ning of spool.
10-87
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
Pressure compensation valve
Function • During compound operations, if the load pressure on either actuator becomes lower than the other actuator and the oil flow is about to increase, compensation is made. [When this happens, the other actuator being used for compound operation (right side) is at a high load than the actuator on this side (left side).] Operation • When the load pressure on the other actuator (right side) becomes higher during compound operations, the oil flow in actuator circuit A on this side (left side) starts increasing. • When this happens, the LS pressure PLS on the other actuator acts on spring chamber PLSS, and reducing valve (1) and flow control valve (2) are pushed to the left.
10-88
•
•
•
Flow control valve (2) throttles the area of opening between pump circuit PP and spool upstream PPA to cause a pressure loss between PP and PPA. Flow control valve (2) and reducing valve (1) are balanced in a position where the difference between PLS and PA acting on both ends of reducing valve (1) and the pressure loss made between PP and PPA on the sides of flow control valve (2) will be the same. In this way, the pressure difference between upstream pressure PPA and downstream pressure PA of both spools used during compound operations is the same, so the pump flow is divided in proportion to the area of opening of notch (a) of each spool.
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
Boom hydraulic drift prevention valve Function • This valve prevents the oil in the boom cylinder bottom from leaking through spool (1) to cause hydraulic drift of the boom while the boom control lever is not operated. 1. When boom is raised
Operation • When the boom is "raised", the main pressure from the control valve pushes up puppet (2). As a result, the hydraulic oil from the control valve flows through the valve into the boom cylinder bottom.
PC78MR-6
10-89
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
2. When boom is held
•
When the boom control lever is returned to the neutral position after the boom is raised, the holding pressure on the boom cylinder bottom side is closed by puppet (2) and the hydraulic oil that flowed through orifices (a1) and (a2) is closed by pilot spool (3). Accordingly, the boom is held.
10-90
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
3. When boom is lowered
•
•
•
When the boom is lowered, pilot pressure P1 from the PPC valve pushes pilot spool (3) and the hydraulic oil in chamber (b) in the puppet is drained. The pressure in port (Ab) is heightened by the hydraulic oil from the boom cylinder bottom, but the pressure in chamber (b) is lowered by orifices (a1) and (a2). When the pressure in chamber b lowers below that in port (Ab), puppet (2) opens and the hydraulic oil from port (Ab) flows through port (Aa) into the control valve.
PC78MR-6
10-91
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
Boom regeneration circuit 1. When boom is lowered by its weight.
Function • While the boom is being lowered by its weight, if bottom pressure A of cylinder (1) is higher than head pressure B, this circuit sends the return oil on the bottom side to the head side to increase the cylinder speed by that amount.
•
•
When this happens, a part of the return oil on the bottom side flows through regeneration passages (a) of bottom spool (2), pushes check valve (3) open, and flows into the head side. As a result, the boom lowering speed is heightened.
Operation • While the boom is being lowered by its weight, pressure A on the bottom side of boom cylinder (1) is higher than pressure B on the head side.
10-92
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
2. When boom is lowered under a load.
Function • While the boom is being lowered under a load, if head pressure B of cylinder (1) is higher than bottom pressure A, check valve (3) is closed to shut off the head side and bottom side from each other. Operation • While the boom is being lowered under a load, pressure B on the head side of boom cylinder (1) is higher than pressure A on the bottom side. • When this happens, check valve (3) is closed by pressure B on the head side and spring (4) to shut off the head side and bottom side from each other.
PC78MR-6
10-93
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
Travel junction valve (L.H., R.H. travel junction circuit) 1. When traveling in a straight line
10-94
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
2. When steered during travel
PC78MR-6
10-95
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
Function • To compensate for any difference in the oil flow in the left and right travel circuits while machine travels in a straight line, the junction circuit opens when the left and right travel spools are operated. • In this way, the flow rates of oil to the left and right travel motors are almost the same when the machine travels in a straight line, so the machine deviates less. • When the machine is steered, the junction circuit opens. Since opening (b) of travel junction valve spool (3) is small, however, the junction circuit does not affect the steering performance. Operation 1. When traveling in a straight line • Since only both travel valves are operated and any work equipment valve is not operated, pump discharge circuits PP1 and PP2 and LS circuits PLS1 and PLS2 are separated by the pump merge-divider spool. (See the section on the LS bypass plug). • When both travel spools (1) are operated, the oil from the pump flows from pump discharge circuits PP1 and PP2 through actuator circuit PB to B. • When the machine travels in straight line, both reducing valves (2) are pushed to the right and notch (a) and travel junction circuit are opened. • The right end of travel junction spool (3) is the work equipment PPC pressure circuit. Since the work equipment valve is not operated at this time, however, any pressure is not generated. • In this way, both travel actuator circuits are interconnected by the travel junction circuit. If any difference occurs in the flow of oil to both travel motors, the difference is compensated to reduce travel deviation. 2. When steered during travel • Since only both travel valves are operated and any work equipment valve is not operated, pump discharge circuits PP1 and PP2 and LS circuits PLS1 and PLS2 are separated by the pump merge-divider spool. (See the section on the LS bypass plug). • The machine is steered by supplying the demand flow to the actuator circuit according to the strokes of both travel spools. (See the section on the unload valve.) • While the machine is traveling in a straight line, if the right travel spool (right 1) is returned to the neutral position and the machine is steered, a difference (left B > right B) is made between the load pressures in both travel actuator circuits PB.
10-96
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
Travel LS bleed circuit and travel junction valve 1. During normal operation
PC78MR-6
10-97
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
CLSS
2. When travel actuator and another actuator are operated
10-98
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
Function • When the travel actuator and another actuator are operated at the same time, the amount of oil discarded through the throttle in LS circuit PLS increases and the pressure compensation precision of the travel circuit is lowered to reduce the drop of the travel speed. • When the travel actuator or any other actuator is operated singly, the LS bleed circuit is closed. • Travel junction valve spool (5) is set to open (b) (small) or open (c) (large) by the boom PPC pressure so that the difference between the flow rates in both travel circuits can be corrected easily.
CLSS
•
For this reason, LS circuit pressure PLS, which is the same pressure as boom circuit pressure A, flows to travel circuit B to reduce the pressure.
Operation 1. During normal operation • When boom spool (1) is operated, LS circuit PLS becomes the same pressure as boom circuit pressure A. • Since the work equipment valve is operated, pump discharge pressures PP1 and PP2 are merged by the pump merge-divider valve spool. LS pressures PLS1, PLS2, and PLS3 are also merged. (See the sections on the pump merge-divider valve and logic valve.) • At the same time, LS pressure PLS also goes to spring chamber PLSS of reducing valve (2) of the travel valve. • Since the travel valve spool is not operated, notch (a) of reducing valve (2) is closed, and check valves (3) and (4) of the bleed circuit are also closed. • As a result, when the boom is operated singly, the travel LS bypass circuit is closed. 2. When travel actuator and another actuator are operated • When boom spool (1) is operated, LS circuit PLS becomes the same pressure as boom circuit pressure A. • Since the work equipment valve is operated, pump discharge pressures PP1 and PP2 are merged by the pump merge-divider valve spool. LS pressures PLS1, PLS2, and PLS3 are also merged. (See the sections on the pump merge-divider valve and logic valve.) • As for the actuator circuit pressure, the boom RAISE pressure is normally higher than the travel pressure (A > B), so the pressure in spring chamber PLSS inside reducing valve (2) of the travel valve is higher than travel circuit pressure PB. • As a result, reducing valve (2) moves to the left and LS pressure PLS flows through check valves (3) and (4) and notch (a) of reducing valve (2) to travel circuit PB.
PC78MR-6
10-99
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SWING MOTOR
SWING MOTOR Model: LMF30AEL
B: From swing brake solenoid valve S: From tank T: To tank MA: From control valve MB: From control valve
Specifications Model: LMF30AEL Capacity: 31 cm3/rev Set pressure of safety valve: 21 MPa {210 kg/cm2} Cracking pressure of check valve: Max. 0.03 MPa {0.30 kg/cm2}
1. Reverse prevention valve
10-100
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
1. 2. 3. 4. 5. 6. 7. 8.
SWING MOTOR
9. 10. 11. 12. 13. 14. 15.
Output shaft Housing Shoe Piston Cylinder block Valve plate Center spring Swash plate
Safety valve Check valve Check valve spring Brake spring Brake piston Disc Plate
Unit: mm No.
Item
Criteria Basic dimension
A
B
Check valve spring
Free length × Outside diameter
Installed length
Installed load
Free length
Installed load
15.5 × 9.0
11.5
0.9 N {0.09 kg}
–
0.69 N {0.07 kg}
33 × 13.8
19.5
1.8 N {0.18 kg}
–
1.41 N {0.14 kg}
Valve return spring
PC78MR-6
Remedy Allowable limit If damaged or deformed, replace spring.
10-101
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SWING MOTOR
BRAKE VALVE Outline • The brake valve consists of a check valve and a safety valve. Function • When the machine stops swinging, control valve (1) closes the outlet circuit of the motor. Since the motor continues revolving because of the inertia, the motor output pressure rises abnormally to break the motor. Accordingly, the abnormally high pressure is released through the outlet (high pressure side) of the motor to protect the motor. Operation 1. When machine starts swinging • When the swing control lever is operated to swing to the left, the hydraulic oil from the pump flows through control valve (1) into port MB. As a result, the pressure in port MB rises and the starting torque is generated in the motor and the motor starts revolution. The oil from the motor outlet returns from port MA through control valve (1) to the tank.
10-102
2. When machine stops swinging • If the swing control lever is returned to the neutral position, oil is not supplied from the pump to port MB any more. Since the return circuit for the oil from the motor outlet to the tank is closed by control valve (1), the pressure in port MA rises and revolution resistance is generated in the motor, then the motor is braked. • The pressure in port MA rises to the set pressure of the safety valve. As a result, high braking torque is generated in the motor, then the motor stops. • While the safety valve is operating, the oil discharged from the safety valve and the oil from port S are supplied through check valve CB to port MB so that cavitation will not occur in port MB.
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SWING MOTOR
MODULATING RELIEF VALVE Function The relief valve for the swing motor prevents the relief pressure from rising sharply to reduce shocks when the machine starts and stops swinging.
Operation 1. When circuit pressure is P0 • The relief valve does not operate. 2. When circuit pressure rises sharply • When circuit pressure rises to P1, the hydraulic pressure acts on the area difference between D1 and D3 (D1 > D3) and pushes spring (4) to open valve (3). • At this time, pressure acts on the area difference between D1 and D2 (D2 > D1), so seat (1) follows valve (3). • As seat (1) moves, the passage for the pressurized oil in chamber (a) to flow into port S is narrowed by ball (2). Accordingly, seat (1) does not move so fast as valve (3). • As a result, the relief pressure rises gradually from P1 to P2 while seat (1) is moving to sleeve (5).
PC78MR-6
10-103
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SWING MOTOR
SWING BRAKE 1. When solenoid valve is de-energized
2. When solenoid valve is energized
Operation • When the solenoid valve of the swing brake is de-energized, the hydraulic oil from the selfpressure reducing valve is shut off and port B is connected to the tank circuit. • As a result, brake piston (13) is pushed up by brake spring (12) to press disc (14) and disc (15) to apply the brake.
Operation • When the solenoid valve of the swing brake is energized, the valve is changed and hydraulic oil from the self-pressure reducing valve flows through port B into brake chamber A. • The hydraulic oil in chamber A pushes brake spring (12) and brake piston (13) moves down. As a result, disc (14) and plate (15) are separated and the brake is released.
10-104
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SWING MOTOR
REVERSE ROTATION PREVENTION LEVEL
MA : MB : T1 : T2 :
Port Port Port Port
PC78MR-6
1. 2. 3. 4. 5. 6. 7.
Valve Body Spool (MA end) Spring (MA end) Plug (MA end) Spool (MB end) Spring (MB end) Plug (MB end)
10-105
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SWING MOTOR
EFFECT EXPLANATION DRAWING
10-106
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SWING MOTOR
Function • This valve reduces the swing back generated in the swing body by the inertia of the swing body, the backlash and rigidity of the machinery system, and the compression of the hydraulic oil when the swing is stopped. • This is effective in preventing spillage of the load when stopping the swing and reducing the cycle time (the positioning ability is good and it is possible to move swiftly to the next job).
1. When brake pressure is being generated at port MB Operation • Pressure MB passes through the notch and goes to chamber d, spool (5) compresses spring (6) according to the difference in area D1 > D2, moves to the left, and MB o e is connected. • When this happens, pressure MA is below the set pressure of spring (3), so spool (2) does not move. For this reason, the pressure oil is closed, and the braking force is ensured.
2. After motor stops Operation • The motor is reversed by the closing pressure generated at port MB. (1st reversal) • When this happens, reversal pressure is generated at port MA. Pressure MA goes to chamber a, compresses spring (3), spool (2) moves to the right, and MA o b is connected. • At the same time, b o f is connected through the drill hole in spool (5), so the reversal pressure at port MA is bypassed to port T to prevent the 2nd reversal.
PC78MR-6
10-107
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
WORK EQUIPMENT AND SWING PPC VALVE
WORK EQUIPMENT AND SWING PPC VALVE
P T P1 P2 P3 P4
: : : : : :
From main pump To tank Left - Arm OUT/Right - Boom LOWER Left - Arm IN/Right - Boom RAISE Left - Swing RIGHT/Right - Bucket CURL Left - Swing LEFT/Right - Bucket DUMP
10-108
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11.
WORK EQUIPMENT AND SWING PPC VALVE
Spool Metering spring Centering spring Piston Disc Nut (For connection of lever) Joint Plate Retainer Body Filter
10-110
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
WORK EQUIPMENT AND SWING PPC VALVE
Unit: mm No.
Item
Criteria Basic dimension
12
13 14
Centering spring (For ports P3 and P4)
Centering spring (For ports P1 and P2) Metering spring
PC78MR-6
Remedy Allowable limit
Free length × Outside diameter
Installed length
Installed load
Free length
Installed load
42.48 × 15.5
34.0
17.65 N {1.80 kg}
–
14.1 N {1.44 kg}
44.45 × 15.5
34.0
29.42 N {3.0 kg}
–
23.5 N {2.40 kg}
26.47 × 8.20
24.9
16.66 N {1.70 kg}
–
13.3 N {1.36 kg}
If damaged or deformed, replace spring.
10-111
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
WORK EQUIPMENT AND SWING PPC VALVE
OPERATION 1. At neutral • Ports A and B of the control valve and ports P1, P2, P3 and P4 of the PPC valve are connected to drain chamber D through fine control hole f in spool (1). (Fig. 1)
2. During fine control (neutral o fine control) • When piston (4) starts to be pushed by disc (5), retainer (9) is pushed; spool (1) is also pushed by metering spring (2), and moves down. • When this happens, fine control hole f is shut off from drain chamber D, and at almost the same time, it is connected to pump pressure chamber PP, so pilot pressure oil passes through fine control hole f and goes from port P1 to port A. • When the pressure at port P1 becomes higher, spool (1) is pushed back and fine control hole f is shut off from pump pressure chamber PP. At almost the same time, it is connected to drain chamber D to release the pressure at port P1. • When this happens, spool (1) moves up or down so that the force of metering spring (2) is balanced with the pressure at port P1. The relationship in the position of spool (1) and body (10) (fine control hole f is at a point midway between drain hole D and pump pressure chamber PP) does not change until retainer (9) contacts spool (1). • Therefore, metering spring (2) is compressed proportionally to the amount of movement of the control lever, so the pressure at port P1 also rises in proportion to the travel of the control lever. • In this way, the control valve spool moves to a position where the pressure in chamber A (the same as the pressure at port P1) and the force of the control valve spool return spring are balanced. (Fig. 2)
10-112
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
WORK EQUIPMENT AND SWING PPC VALVE
3. During fine control (when control lever is returned) • When disc (5) starts to be returned, spool (1) is pushed up by the force of centering spring (3) and the pressure at port P1. • When this happens, fine control hole f is connected to drain chamber D and the pressure oil at port P1 is released. • If the pressure at port P1 drops too far, spool (1) is pushed down by metering spring (2), and fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, and the pump pressure is supplied until the pressure at port P1 recovers to a pressure that corresponds to the lever position. • When the spool of the control valve returns, oil in drain chamber D flows in from fine control hole f in the valve on the side that is not working. The oil passes through port P2 and enters chamber B to fill the chamber with oil. (Fig. 3)
4. At full stroke • When disc (5) pushes down piston (4), and retainer (9) pushes down spool (1), fine control hole f is shut off from drain chamber D, and is connected with pump pressure chamber PP. • Therefore, the pilot pressure oil passes through fine control hole f and flows to chamber A from port P1, and pushes the control valve spool. • The oil returning from chamber B passes from port P2 through fine control hole f and flows to drain chamber D. (fig. 4)
PC78MR-6
10-113
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRAVEL PPC VALVE
TRAVEL PPC VALVE
P T P1 P2 P3 P4
: : : : : .
From main pump To tank Left travel reverse Left travel forward Right travel reverse Right travel forward
10-114
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
1. 2. 3. 4.
TRAVEL PPC VALVE
5. 6. 7. 8.
Plate Body Piston Collar
Metering spring Centering spring Valve Bolt Unit: mm
No.
Item
Criteria Basic dimension
9
10
Metering spring
Centering spring
PC78MR-6
Remedy Allowable limit
Free length × Outside diameter
Installed length
Installed load
Free length
Installed load
26.53 × 8.15
24.9
16.7 N {1.70 kg}
–
13.3 N {1.36 kg}
52.06 × 15.5
31.9
135.2 N {13.8 kg}
–
108 N {11.04 kg}
If damaged or deformed, replace spring.
10-115
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRAVEL PPC VALVE
OPERATION 1. At neutral • Ports A and B of the control valve and ports P1 and P2 of the PPC valve are connected to drain chamber D through fine control hole f in spool (1). (Fig. 1)
2. During fine control (neutral o fine control) • When piston (4) starts to be pushed by disc (5), retainer (9) is pushed; spool (1) is also pushed by metering spring (2), and moves down. • When this happens, fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, and the pilot pressure is sent from port A through fine control hole f to port P1 . • When the pressure at port P1 rises, spool (1) is pushed back. Fine control hole f is shut off from pump pressure chamber PP. At almost the same time, it is connected to drain chamber D to release the pressure at port P1. • As a result, spool (1) moves up and down until the force of metering spool (2) is balanced with the pressure of port P1. • The relationship in the position of spool (1) and body (10) (fine control hole f is in the middle between drain hole D and pump pressure chamber PP) does not change until retainer (9) contacts spool (1). • Therefore, metering spring (2) is compressed in proportion to the travel of the control lever, so the pressure at port P1 also rises in proportion to the travel of the control lever. • In this way, the control valve spool moves to a position where the pressure of chamber A (same as pressure at port P1) and the force of the return spring of the control valve spool are balanced. (Fig. 2)
10-116
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
TRAVEL PPC VALVE
3. Fine control (control lever returned) • When disc (5) starts to be returned, spool (1) is pushed up by the force of centering spring (3) and the pressure at port P1. • Because of this, fine control hole f is connected to drain chamber D, and the pressurized oil at port P1 is released. • If the pressure at port P1 drops too much, spool (1) is pushed up by metering spring (2), so fine control hole f is shut off from drain chamber D. At almost the same time, it is connected to pump pressure chamber PP, so the pressure at port P1 supplies the pump pressure until the pressure recovers to a pressure equivalent to the position of the lever. • When the control valve returns, oil in drain chamber D flows in from fine control hole f of the valve on the side that is not moving. It passes through port P2 and enters chamber B to fill the chamber with oil. (Fig. 3)
4. At full stroke • Disc (5) pushes down piston (4), and retainer (9) pushes down spool (1). Fine control hole f is shut off from drain chamber D, and is connected to pump pressure chamber PP. • Therefore, the pilot pressure oil passes through fine control hole f and flows to chamber A from port P1 to push the control valve spool. • The return oil chamber B passes from port P2 through fine control hole f and flows to drain chamber D. (fig. 4)
PC78MR-6
10-117
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
BOOM SWING PPC VALVE, BLADE PPC VALVE
BOOM SWING PPC VALVE BLADE PPC VALVE
T P P1 P2
: : : :
To tank From main pump To right boom swing/blade raise valve To left boom swing/blade lower valve
1. 2. 3. 4. 5.
Spool Metering spring Centering spring Piston Lever
10-118
6. 7. 8. 9.
Plate Retainer Body Filter
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
BOOM SWING PPC VALVE, BLADE PPC VALVE
For Boom Swing Unit: mm No.
Item
Criteria Basic dimension
10
11
Centering spring
Metering spring
Remedy Allowable limit
Free length × Outside diameter
Installed length
Installed load
Free length
Installed load
33.88 × 15.3
28.4
124.5 N {12.7 kg}
–
100 N {10.2 kg}
22.73 × 8.1
22.0
16.67 N {1.70 kg}
–
13.3 N {1.36 kg}
If damaged or deformed, replace spring.
For Blade Unit: mm No.
Item
Criteria Basic dimension
10
11
Centering spring
Metering spring
PC78MR-6
Remedy Allowable limit
Free length × Outside diameter
Installed length
Installed load
Free length
Installed load
42.36 × 15.5
32.5
14.7 N {15 kg}
–
118 N {12 kg}
22.73 × 8.1
22.0
16.67 N {1.7 kg}
–
13.3 N {1.36 kg}
If damaged or deformed, replace spring.
10-119
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
BOOM SWING PPC VALVE, BLADE PPC VALVE
Operation 1. In the neutral mode • P1 and P2 ports of the operation valves A, B and PPC valve are connected to drain room D via the fine control hole f on the spool (1).
2. In the fine control mode (Neutral o fine control) • As the piston (4) is pushed by disk (5), the retainer (7) is pushed too. At the same time, the spool (1) is also pushed down via the metering spring (2). • By this move, connection of the fine control hole f is switched from the drain room D to the pump pressure room PP, and pilot pressure oil for the control pump is conducted from P1 port to A port. • As P1 port pressure increases, the spool (1) is pushed back. By this move, connection of the fine control hole f is switched from the pump pressure room PP to the drain room D, thereby relieving P1 port pressure. • As the result, the spool (1) moves up and down so that force of the metering spring (2) and P1 port pressure may be balanced. • Positional relationship between the spool (1) and body (8) (fine control hole f is situated at mid point between the drain room D and pump pressure room PP) remains unchanged until the retainer (7) is contacted against the spool (1). • The metering spring (2) is, therefore, compressed in proportion to strokes of the operation lever. Thus, the P1 port pressure too, increases in proportion to strokes of the operation lever. • As the result, the operation valve spool moves to the position where the pressure of A room (the same as P1 port pressure) is balanced against force of the operation valve spool return spring.
10-120
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
BOOM SWING PPC VALVE, BLADE PPC VALVE
3. In the fine control mode (when the operation lever is shifted back to its original position) • As the lever (5) starts returning, the spool (1) is pushed up by force of the centering spring (3) and P1 port pressure. By this move, the fine control hole f is connected to the drain room D and relieves pressurized oil of P1 port to it. • If P1 port pressure goes excessively low, the spool (1) is pushed down by the metering spring (2), and passage between fine control hole f and drain room D is shut down. And, almost at the same time, the hole is connected to the pump pressure room PP and starts supplying pump the pressure. This supply continues until the P1 port pressure is recovered to the level equivalent to the lever position. • When the operation valve spool returns, oil in the drain room D flows in through the fine control hole f on the not moving side valve. Oil is then conducted via P2 port to the room B to fill it up. 4. In the full stroke mode • When the disk (5) pushes down piston (4) and the retainer (7) pushes down the spool (1), connection of the fine control hole f is switched from the drain room D, to the pump pressure room PP. • Thus, pilot pressurized oil from the control pump passes through fine control hole f and conducted to A room via P1 port to push the operation valve spool. • Return oil from B room is conducted from P2 port to the drain room D via the fine control hole f.
PC78MR-6
10-121
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
BOOM HYDRAULIC ANTI-BURST VALVE
BOOM HYDRAULIC ANTI-BURST VALVE (FOR EU SPEC.)
V : From control valve T : To hydraulic tank CY : To hydraulic cylinder PI : From PPC valve PCY: For pressure pickup and equalizer circuits
10-121-1 (1)
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
1. 2. 3. 4. 5. 6.
BOOM HYDRAULIC ANTI-BURST VALVE
Pilot spool Spring (1st stage of spool) Spring (2nd stage of spool) Safety valve Check valve Spring Unit: mm
No.
Item
Criteria Basic dimension
7
Check valve spring
Remedy Allowable limit
Free length x Outside diameter
Installed length
Installed load
Free length
Installed load
16.4 x 8.9
11
14.7 ± 1.5 N {1.5 ± 0.15 kg}
—
10.8 N {1.1 kg}
8
Spool return spring
19.1 × 8
13.5
24.7 ± 1.5 N {2.52 ± 0.15 kg}
—
18.6 N {1.9 kg}
9
Spool return spring
24.8 × 16.8
22.5
55.4 ± 3.0 N {5.65 ± 0.3 kg}
—
42.2 N {4.3 kg}
PC78MR-6
If damaged or deformed, replace spring
10-121-2 (1)
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
BOOM HYDRAULIC ANTI-BURST VALVE
Function If the piping between the main valve and a work equipment cylinder bursts, this valve prevents the oil from flowing back from the work equipment cylinder to prevent sudden fall of the work equipment. Operation 1. When the work equipment is in neutral [When piping is normal] • Check valve (5) is closed by the work equipment cylinder holding pressure applied through port CY to chamber b. • When the work equipment is in neutral, no pilot pressure is applied from the PPC valve to port PI. Accordingly, pilot spool (1) is moved to the left end by the force of springs (2) and (3), then chambers a and b are shut off from each other. • Accordingly, oil does not flow from the main valve to the work equipment cylinder, thus the work equipment cylinder is held. • If the pressure in the work equipment cylinder rises high abnormally, work equipment cylinder holding pressure Pb operates safety valve (4). [When piping bursts] • Even if piping A between the main valve and work equipment cylinder bursts, chamber a is shut off from chanber b as in the case where the piping is normal. Accordingly, the work equipment cylinder is held. • When the engine is stopped and the work equipment is held in air, if port PCY is opened, oil in chamber b flows out through orifice (7) and port PCY. Accordingly, the work equipment lowers slowly.
10-121-3 (1)
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
BOOM HYDRAULIC ANTI-BURST VALVE
2. When oil is sent from main valve to cylinder [When piping is normal] • If pressure Pa of the oil sent from the main valve to chamber a is higher than the total of pressure Pb in chamber b connected to the work equipment cylinder and the force of spring (6), check valve (5) opens and chambers a and b are connected to each other and the oil flows from the main valve to the work equipment cylinder. [When piping bursts] • If piping A between the main valve and the work equipment cylinder bursts, the oil in chamber a flows out through the burst part and pressure Pa in chamber a lowers. • If Pa lowers below the total of pressure Pb in chamber b and the force of spring (6), check valve (5) closes and chambers a and b are shut off from each other. Accordingly, pressure Pb in the cylinder is held and the work equipment does not fall suddenly.
PC78MR-6
10-121-4 (1)
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
BOOM HYDRAULIC ANTI-BURST VALVE
3. When oil is returned from work equipment cylinder to main valve [When piping is normal] • The work equipment cylinder holding pressure is applied to chamber b and check valve (5) closes. • The pilot pressure from the PPC valve is applied to port PI. If it is higher than the force of spring (2) (area of ø d), spool (1) moves to the right standby position (1st-stage stroke). • At this time, chambers a and b are not connected to each other. • If the pilot pressure rises higher than the force of spring (3) (area of ø d), spool (1) moves further to the right and chambers a and b are connected to each other (2ndstage stroke). • Accordingly, the oil is returned from the work equipment cylinder to the main valve. [When piping bursts] • If piping A between the main valve and work equipment cylinder bursts, the oil in chamber a flows out through the burst part. Since oil supplied from chamber b to chamber a flows through opening c of spool (1), however, the work equipment does not fall suddenly. •
If the PPC valve is returned to the neutral position, spool (1) returns to the left end to shut off chambers a and b from each other. Accordingly, the work equipment stops.
10-121-5 (1)
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
WORK EQUIPMENT
WORK EQUIPMENT
Unit : mm
Item
No.
1
Clearance between swing bracket and revolving frame mounting pin and bushing
Criteria Standard size
Tolerance
Remedy
Shaft
Hole
Standard clearance
Clearance limit
110
-0.036 -0.090
+0.204 +0.125
0.161 – 0.294
1.0
2
Clearance between boom and swing bracket mounting pin and bushing
65
-0.030 -0.100
+0.174 +0.100
0.130 – 0.274
1.0
3
Clearance between boom and arm mounting pin and bushing
60
-0.030 -0.100
+0.174 +0.100
0.130 – 0.274
1.0
4
Clearance between arm and bucket mounting pin and bushing
50
-0.225 -0.285
-0.062 -0.120
0.105 – 0.223
1.0
5
Clearance between arm and link mounting pin and bushing
50
-0.225 -0.285
-0.062 -0.120
0.105 – 0.223
1.0
6
Clearance between link and link mounting pin and bushing
60
-0.030 -0.100
+0.173 +0.100
0.130 – 0.273
1.0
7
Clearance between bucket and link mounting pin and bushing
50
-0.225 -0.285
-0.040 -0.094
0.131 – 0.245
1.0
8
Clearance between blade and track frame mounting pin and bushing
50
-0.025 -0.087
+0.142 +0.080
0.105 – 0.229
1.0
10-122
Replace pin and bushing
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
PC78MR-6
WORK EQUIPMENT
10-123
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
DIMENSIONS OF EACH PART OF WORK EQUIPMENT
DIMENSIONS OF EACH PART OF WORK EQUIPMENT 1. ARM SECTION
10-124
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
DIMENSIONS OF EACH PART OF WORK EQUIPMENT
PC78MR-6 No.
Measuring point
1
2
– Arm side Cylinder head side
3
Basic dimension 60
Allowance Shaft
Hole
-0.030 -0.100
+0.100 0
71.5
+1.0 0
70
±1.2 -0.030 -0.100
+0.100 0
–
60
Boom side
220
+0.5 0
Arm side
220
-0.5 -1.0
4
5
–
142.4
±2.0
6
–
218.8
±1.0
7
–
458.6
±1.0
8
–
1,650
–
9
–
2,093.9
±3.0
10
–
1,661.2
±1.3
11
–
258.7
±0.3
12
–
15.1
±1.0
13
–
395.1
±0.1
14
–
342
±0.1
15
–
312.2
–
16
–
1,066.9
–
17
–
50
-0.225 -0.285
Link side
200
-1.0 -2.0
Bucket side
200
+2.0 0
–
50
18
19
PC78MR-6
-0.225 -0.285
0 -0.150
Arm side
188
-0.50 -1.0
Bucket side
211
+3.0 0
Min.
1,055
±1.5
Max.
1,765
–
20
21
0 -0.150
10-125
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
DIMENSIONS OF EACH PART OF WORK EQUIPMENT
2. BUCKET PORTION
10-126
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
No.
DIMENSIONS OF EACH PART OF WORK EQUIPMENT
PC78MR-6 Measuring point
Basic dimension
Allowance
1
–
309.8
±0.5
2
–
38.6
±0.5
3
–
97.1°
–
4
–
312.2
–
5
–
1,057.2
–
6
–
143.7
–
7
–
8°
–
8
–
5.2°
–
9
–
50
0 -0.15
10
–
60
–
11
–
70
+0.2 0
12
–
200
+2.0 0
13
–
40
–
14
–
71
–
15
–
296
+1.0 0
16
–
18
–
17
–
100
–
18
–
115
–
19
–
95
–
20
–
211
+3.0 0
21
–
40
–
22
–
24
–
23
–
89.3
–
24
–
87.9
–
25
–
60
–
26
–
66
–
PC78MR-6
10-127
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
AIR CONDITIONER PIPING
AIR CONDITIONER PIPING (OPTIONAL)
A: Hot/Cool air outlet B: Inside air circulation opening C: Fresh air inlet
10-128
1. 2. 3. 4. 5. 6. 7. 8.
Hot water take-out piping Air conditioner compressor Hot water return piping Refrigerant piping Condenser Receiver drier Air conditioner unit Duct
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
ELECTRIC CONTROL SYSTEM Engine control function
Engine and pump compound control function
Overheat prevention function
Swing control function
Travel control function
PPC lock function (*1) Electric control system
Overload alarm function
Error code display and alarm function Self-diagnosis function Error code memory func
*1. For EU spec. machine only.
PC78MR-6
10-129 (1)
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
GENERAL SYSTEM DIAGRAM (FOR STD SPEC.)
10-130 (1)
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
1. 2. 3. 4. 5. 6. 7. 8.
Battery Battery relay Fusible link Starting switch Fuse box Controller Emergency pump drive switch Emergency boom swing operating and swing holding brake release switch 9. Resistor (For emergency boom swing operating) 10. Resistor (For emergency pump drive) 11. Safety lock lever 12. PPC lock switch 13. Starting motor cut relay 14. Safety relay 15. One-touch deceleration switch 16. Fuel control motor relay (For accelerator) 17. Fuel control motor relay (For deceleration) 18. Fuel control dial 19. Fuel control motor 20. Monitor panel 21. Travel speed boost pedal 22. Travel alarm (If equipped) 23. PPC lock solenoid valve 24. 2-stage travel speed selector solenoid valve 25. Swing holding brake solenoid valve 26. Left boom swing stop EPC valve 27. Right boom swing stop EPC valve 28. TVC-EPC valve 29. Right work equipment PPC valve 30. Travel PPC valve 31. Left work equipment PPC valve 32. Boom swing PPC valve 33. Blade PPC valve 34. Attachment control PPC valve 35. Boom RAISE PPC oil pressure switch 36. Travel PPC oil pressure switch 37. Arm IN PPC oil pressure switch 38. Swing PPC oil pressure switch 39. Boom swing potentiometer 40. Engine stop solenoid 41. Engine stop solenoid relay 42. Starting motor 43. Engine speed sensor 44. Coolant temperature sensor 45. Hydraulic pump 45a. Servo piston 45b. LS valve 45c. TVC valve 46. Control valve 46a. Pump merge-divider valve 47. Travel motor 48. Swing motor
PC78MR-6
10-131
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
GENERAL SYSTEM DIAGRAM (FOR EU SPEC.)
10-131-1 (1)
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
1. 2. 3. 4. 5. 6. 7. 8.
Battery Battery relay Fusible link Starting switch Fuse box Controller Emergency pump drive switch Emergency boom swing operating and swing holding brake release switch 9. Resistor (For emergency boom swing operating) 10. Resistor (For emergency pump drive) 11. Safety lock lever 12. PPC lock switch 13. Starting motor cut relay 14. Safety relay 15. One-touch deceleration switch 16. Fuel control motor relay (For accelerator) 17. Fuel control motor relay (For deceleration) 18. Fuel control dial 19. Fuel control motor 20. Monitor panel 21. Travel speed boost pedal 22. Travel alarm (If equipped) 23. PPC lock solenoid valve 24. 2-stage travel speed selector solenoid valve 25. Swing holding brake solenoid valve 26. Left boom swing stop EPC valve 27. Right boom swing stop EPC valve 28. TVC-EPC valve 29. Right work equipment PPC valve 30. Travel PPC valve 31. Left work equipment PPC valve 32. Boom swing PPC valve 33. Blade PPC valve 34. Attachment control PPC valve 35. Boom RAISE PPC oil pressure switch 36. Travel PPC oil pressure switch 37. Arm IN PPC oil pressure switch 38. Swing PPC oil pressure switch 39. Boom swing potentiometer 40. Engine stop solenoid 41. Engine stop solenoid relay 42. Starting motor 43. Engine speed sensor 44. Coolant temperature sensor 45. Hydraulic pump 45a. Servo piston 45b. LS valve 45c. TVC valve 46. Control valve 46a. Pump merge-divider valve 47. Travel motor 48. Swing motor 49. Overload alarm actuation switch 50. Overload alarm pressure switch
PC78MR-6
10-131-2 (1)
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
ENGINE CONTROL FUNCTION
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19.
Battery Battery relay Fusible link Starting switch Fuse box Controller Safety lock lever PPC lock switch Starting motor cut relay Safety relay Fuel control dial Fuel control motor Fuel control motor relay (For accelerator) Fuel control motor relay (For deceleration) One-touch deceleration switch Monitor panel Engine stop solenoid Engine stop solenoid relay Starting motor
10-132
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
Starting engine • If starting switch (4) is turned to the ON position, engine stop solenoid (17) moves governor stop lever to the "RUN" side. Accordingly, if the electric system has any trouble, the engine stops, that is, a fail-safe mechanism is formed. • If starting switch (4) is turned to the START position while safety lock lever (7) is at the "LOCK" position, the start signal flows to starting motor (19) and the engine starts. If safety lock lever (7) is at the "FREE" position, the start signal to starting motor (19) is cut out by starting motor cut relay (9) and the engine cannot start. • At this time, since fuel control motor (12) is linked with fuel control dial (11), the engine speed is fixed to the speed set with fuel control dial (11). Controlling engine speed • Fuel control motor (12) outputs the acceleration (engine speed raising) signal and deceleration (engine speed lowering) signal to controller (6) according to the position of fuel control dial (11). • Upon receiving the signal, controller (6) outputs the drive signal through fuel control motor relays (13) and (14) to fuel control motor (12). • Fuel control motor (12) lengthens or shortens the cable to control the engine speed according to the drive signal.
PC78MR-6
ELECTRIC CONTROL SYSTEM
Function of preventing engine stop solenoid from burning • Engine stop solenoid relay (18) is installed to prevent engine stop solenoid (17) from burning. • The time to supply the suction current is limited to 3 seconds after starting switch (4) is turned to the ON position by replacing the 2-wire engine stop solenoid (17) (which uses the same wire for the suction and holding currents) with the 3-wire one (which uses independent wires for the suction and holding currents) and adding a timer function and engine stop solenoid relay (18) to controller (6).
A: B: C: t:
Operation of starting switch Suction coil current Holding coil current 3 seconds
10-133
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
Stopping engine • If starting switch (4) is turned to the OFF position, engine stop solenoid (17) moves the governor stop lever to the STOP side and the engine stops. One-touch deceleration • If one-touch deceleration switch (16) is pressed, the deceleration signal is output to controller (6). • Controller (6) turns on the one-touch deceleration monitor of monitor panel (16) and drives fuel control motor (12) to lower the engine speed to low idling. • If one-touch deceleration switch (15) is pressed while the engine is being started, the engine speed is set to low idling. If it is pressed again, the engine speed returns to the speed set with fuel control dial (11). a Even if the engine is stopped while the onetouch deceleration system is turned on, the latter is turned off when the engine is started next time (the engine speed is set the speed set with the fuel control dial). a Even if the fuel control dial is operated while the one-touch deceleration system is turned on, the engine speed is kept at low idling. a If the fuel control dial is at low idling, the engine speed does not lower any more even if the onetouch deceleration switch is pressed
A: B: C: D: E:
One-touch deceleration switch [ON] One-touch deceleration switch [OFF] Engine speed set with fuel control dial Low idling Max. 1 sec
10-134
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
ENGINE AND PUMP COMPOUND CONTROL FUNCTION
1. Battery 2. Battery relay 3. Fusible link 4. Starting switch 5. Fuse box 6. Controller 7. Emergency pump drive switch 8. Resistor (For emergency pump drive) 9. Monitor panel 10. TVC-EPC valve 11. Engine speed sensor 12. Coolant temperature sensor 13. Control valve 13a. Pump merge-divider valve 14. Hydraulic pump 14a. Servo piston 14b. LS valve 14c. TVC valve
PC78MR-6
Input/Output signals a. Controller power source b. Solenoid power source c. Monitor panel power source d. S-NET signal e. Coolant temperature signal f. Engine speed signal g. EPC valve drive signal
10-135
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
Functions • The "active" or "E" mode is selected with the working mode selection switch on the monitor panel. In each mode, proper engine torque and pump absorption torque are selected according to the contents of work. • The controller detects the engine governor speed set with the fuel control dial and the actual engine speed and controls the hydraulic system so that the pump will absorb the all torque at each output point of the engine, according to the pump absorption torque set for each mode. • If the engine speed is lowered, the pump absorption torque is reduced to prevent the engine from stopping.
10-136
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
Control method in each mode Active mode • Matching point of active mode: Active mode
•
40.5 kw / 1.850 rpm {54.0 HP / 1.850 rpm}
If the pump load increases and the pressure rises, engine speed lowers. At this time, the pump discharge is reduced to heighten the engine speed to near the full output point. On the other hand, if the pressure lowers, engine speed is heightened to near the full output point to increase the pump discharge. The engine is constantly used near the full output point by repeating this control.
PC78MR-6
10-137
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
E mode • Matching point of E mode: 85% partial output point
E mode
•
•
37.5 kw / 1.660 rpm {50.0 HP / 1,660 rpm}
In this mode, the engine speed is lowered along the constant horsepower curve of the engine, keeping the pump absorption torque at a constant level. The engine is used in the high fuel efficiency area by this control method.
10-138
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
Driving pump in an emergency •
Even if the controller, etc. has a problem and the hydraulic pump does not operate normally, the operator can work temporarily by operating the emergency pump drive switch (S). (1) Auto: Normal state (2) Cancel: Abnormal state
a The emergency pump drive switch (S) is of alternative type. If it is set to the "CANCEL (2)" position while the machine is normal, user code "E02" is displayed on the display unit.
OVERHEAT PREVENTION FUNCTION a For the system circuit diagram, see "Engine and pump compound control function". •
If the coolant temperature rises too high, the pump load is lowered to prevent the engine from overheatin
Operation
Operating condition • Coolant temperature is above 99°C
PC78MR-6
Pump absorption torque is reduced according to torque control system to reduce engine load. (Matching point: 90% partial output point) • Engine speed is kept as it is.
Resetting condition
• Coolant temperature is below 95°C
10-139
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
SWING CONTROL FUNCTION
1. Battery 2. Battery relay 3. Fusible link 4. Starting switch 5. Fuse box 6. Controller 7. Swing holding brake release switch 8. Swing holding brake solenoid valve 9. Swing motor 10. Left work equipment PPC valve 11. Arm IN PPC oil pressure switch 12. Swing PPC oil pressure switch 13. Engine 14. Hydraulic pump 15. Control valve 15a. Pump merge-divider valve 16. Boom swing potentiometer
10-140
Input/Output signals a. Controller power source b. Solenoid power source c. Solenoid valve drive signal d. Swing PPC oil pressure switch signal e. Arm IN PPC oil pressure switch signal f. Boom swing potentiometer signal
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
Function
Relationship between swing holding brake cancel switch and swing holding brake
Swing holding brake • When the machine stops swinging, the swing holding brake is applied automatically to prevent hydraulic drift on a slope, etc. • When the arm is moved in, the swing holding brake is released to reduce the load on the swing unit during digging work. • The swing holding brake is released automatically when the boom swings to reduce the shocks made at each start and stop of swinging. a If the swing holding brake is released, only the hydraulic brake of the safety valve is used to stop swinging. Accordingly, if the machine stops swinging on a slope, etc. the boom may drift hydraulically. Take care.
Swing holding brake cancel switch
Releasing swing holding brake • Even if the controller, etc. has a problem and the swing holding brake does not operate normally and the machine does not swing, the operator can swing the machine by releasing the swing holding brake with the swing holding brake cancel switch (S). (1) Auto: Normal state (2) Cancel: Abnormal state a Emergency swing holding brake cancel switch (S) is of alternative type. If it is set to the "CANCEL (2)" position while the machine is normal, user code "E03" or "E41" are displayed on the display unit.
PC78MR-6
Operation
• If swing control lever or arm IN lever is set to neutral position, swing holding brake is applied about 5 seconds later. • If swing control lever or arm IN Auto lever is operated, swing holding (Normal state) brake is released and machine can swing freely. • The swing holding brake is applied and released according to boom swing operation.
Cancel (Abnormal state)
• When swing holding brake system has trouble, if swing holding brake cancel switch (S) is set to "Cancel (2)", swing holding brake is released and machine can swing. • Even if swing control lever or arm IN lever is set to neutral position, swing holding brake does not operate, however. • The swing holding brake does not work even if the boom swing pedal is in neutral.
Time chart of input and output signals
10-141
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
TRAVEL CONTROL FUNCTION
10-142
a When the engine is started, the travel speed boost selector switch is set to the low speed position automatically. a The travel speed boost pedal is effective only while the "Lo" lamp of the travel speed boost selector switch is lighting. Even if the pedal is pressed while the "Hi" lamp is lighting up, the travel speed does not change. Travel speed boost selector switch
Released
Input/Output signals a. Controller power source b. Solenoid power source c. Monitor panel power source d. S-NET drive signal e. Solenoid valve drive signal f. Travel PPC oil pressure switch signal g. Travel alarm drive signal h. 2nd travel speed selection signal
Function Changing travel speed • If the travel speed boost selector switch is operated or the travel speed boost pedal is pressed, the motor capacity changes to change the travel speed.
Pressed
Battery Battery relay Fusible link Starting switch Fuse box Controller Monitor panel 2-stage travel speed selector solenoid valve Left travel motor Right travel motor Travel PPC valve Travel PPC oil pressure switch Travel alarm (If equipped) Engine Hydraulic pump Control valve Pump merge-divider valve Travel speed boost pedal
Travel speed boost pedal
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 16a. 17.
Lo lamp Hi lamp lights up lights up (Low speed) (High speed)
Motor capacity (cc/rev)
36.3
24.1
Travel speed (km/h)
3.0
4.5
Swash plate angle of travel motor
Max.
Min.
Motor capacity (cc/rev)
24.1
24.1
Travel speed (km/h)
4.5
4.5
Swash plate angle of travel motor
Min.
Min.
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
PPC LOCK FUNCTION
1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16.
Battery Battery relay Fusible link Starting switch Fuse box Controller Safety lock lever PPC lock switch PPC lock solenoid valve Left work equipment PPC valve Right work equipment PPC valve Travel PPC valve Blade PPC valve Engine Hydraulic pump Boom swing PPC valve
PC78MR-6
Input/Output signals a. Controller power source b. Solenoid power source c. Solenoid valve drive signal Function • The PPC lock switch is linked with the safety lock lever. If the safety lock lever is set to the LOCK position, the PPC lock switch is turned OFF. • If the PPC lock switch is turned OFF, the current to the PPC lock solenoid valve is cut out and the work equipment does not move any more even if the work equipment control lever is operated.
10-143
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
OVERLOAD ALARM FUNCTION (FOR EU SPEC.)
1. 2. 3. 4. 5. 6. 7. 8. 9.
Battery Battery relay Fusible link Starting switch Fuse box Controller Monitor panel Overload alarm actuation switch Overload alarm pressure switch
Input/Output signals a. Power supply of controller b. Power supply of solenoids c. Power supply of monitor panel d. S-NET signal e. Overload alarm actuation signal f. Overload alarm pressure signal
Function • If the pressure in the boom cylinder bottom circuit rises above the set value, the caution lamp lights up and the buzzer sounds to notify the operator of possibility of tipping over of the machine by an overload.
10-143-1 (1)
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
BOOM SWING END CUSHION FUNCTION •
When the boom is swung, the boom swing speed is reduced before each stroke end to reduce the shock made at the stroke end. This function reduces the spillage of soil and the load on the chassis.
1. Decelerating function •
•
•
If the boom swings and enters area (B) from area (A), its swing speed is lowered gradually to reduce the shock made at the stop position. At this time, the output pressure from the boom swing PPC valve to the boom swing control valve is reduced by controlling the EPC valve according to the angle sensor signal. As a result, the shock made at the stroke end is reduced.
2. Correction function •
•
If the potentiometer is replaced or the work equipment is replaced, an input signal error is made because of the error of the installation of the potentiometer. With the correction function, this error can be corrected easily without measuring the output voltage or adjusting the potentiometer finely. If the boom is swung to each stroke and the set angle (0) is input, the difference between angle (A) calculated from the actual output voltage of the potentiometer and standard angle (B) set in the computer (installation error) is saved as "correction value (C)".
A. Ordinary area B. Deceleration area
10-144
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
ELECTRIC CONTROL SYSTEM
SELF-DIAGNOSTIC FUNCTION 1. Error code display and alarm function • The system of this function consists of the controller and the electronic components such as the potentiometers that output input signals and the solenoid valves and EPC valves that receive output signals. The controller is constantly checking that those electronic component and itself are functioning normally. • If a problem occurs in any of these components, the controller carries out troubleshooting and displays the result as a "user code" or "service code" on the display unit (1) of the monitor panel and turns on the alarm buzzer to warn the operator of the trouble. a For details of the display and action to take, see TESTING AND ADJUSTING.
PC78MR-6
2. Error code memory function • If a problem occurs in the leading system, it is detected by the self-diagnostic function and its error code is stored in memory. a For details of the display and resetting method, see TESTING AND ADJUSTING.
10-145
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SYSTEM COMPONENTS
SYSTEM COMPONENTS Fuel control dial
1. Fuel control dial 2. Fuel control motor
10-146
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SYSTEM COMPONENTS
Fuel control motor
1. Motor assembly 2. Cable 3. Connector
Input and output signals SWP-6P [CN-K27] Pin No.
PC78MR-6
Signal name
Input/Output signal
1
Motor acceleration signal
2
Power source
Input
3
One-touch deceleration signal
4
Motor deceleration signal
5
Acceleration signal
Output
6
Deceleration signal
Output
– Output Input
10-147
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SYSTEM COMPONENTS
CONTROLLER
Input/output signals DEUTSCH-24P [CN-M95] Pin No. 1 2 3 4 5 6 7 8 9 10 11 12
Signal name NC (*1) NC (*2) Boom cylinder bottom presser sensor NC GND (Signal) 2-stage travel speed selection switch Arm IN PPC oil pressure switch NC Boom swing angle NC GND signal NC Boom RAISE PPC oil pressure switch
I/O signal
Pin No.
– – Input – – Input Input – Input – – – Input
13 14 15 16 17 18 19 20 21 22 23 24
Signal name NC NC NC NC Attachment 1 Travel PPC oil pressure switch NC NC GND (Analog) Sensor power source (+5 V) NC Swing PPC oil pressure switch
I/O signal – – – – Input Input – – – Output – Input
*1. Serial No.: 1001 – 1094 *2. Serial No.: 1095 and up
10-148 (1)
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SYSTEM COMPONENTS
DEUTSCH-40P (1) [CN-M96] Pin No.
Signal name
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
NC NC NC NC NC NC UU/US selection signal NC NC NC NC NC NC NC Back-up light signal Main monitor selection signal Attachment 3 NC NC NC
I/O signal
Pin No.
– – – – – – Input – – – – – – – Input Input Input – – –
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
I/O signal
Pin No.
Signal name
I/O signal
Input Input – Output Output – Output – Input Input Input Input – Input Output Output Output – Input – Input
21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40
GND (Controller) Solenoid power source GND (Solenoid) Key signal Governor motor relay (For acceleration) NC 2-stage travel speed selector solenoid valve NC Deceleration signal NC GND (Controller) GND (Controller) GND (Controller) NC Governor motor relay (For deceleration) NC NC NC Auto-deceleration signal NC
– Input – Input Output – Output – Input – – – – – Output – – – Input –
Signal name S-NET NC NC NC Signal for selecting Tire 2 NC Mode selection 2 – GND (Pulse) MR selection signal GND (S-NET) NC NC GND (232C) NC NC Model selection 1 NC GND (Pulse) Engine speed sensor (+)
I/O signal Input/Output – – – Input – Input – – Input – – – – – – Input – – Input
DEUTSCH-40P (2) [CN-M97] Pin No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
Signal name Controller power Solenoid power GND (Solenoid) Engine stop solenoid relay Left boom swing stop EPC valve NC Swing holding brake solenoid valve NC One-touch deceleration switch Air conditioner compressor signal Controller power Solenoid power GND (Solenoid) Key signal Right boom swing stop EPC valve TVC-EPC vlave Swing and travel alarm NC Acceleration signal (*1) NC (*2) Alarm actuation switch
*1 Serial No.: 1001 – 1094 *2 Serial No.: 1095 and up
PC78MR-6
10-149 (1)
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SYSTEM COMPONENTS
Potentiometer
1. Shaft 2. Housing 3. Bearing
4. Brush 5. Resistor 6. Connector
Functions • A potentiometer is installed on each of the boom feet, arm foot and second boom top to detect the angle of the boom, arm and offset work equipment. • Using the resistance value of the variable resistor, potentiometers send angle data to the controller by converting the supply voltage (5V) into signal voltage according to the angle of the work equipment.
10-150
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SYSTEM COMPONENTS
Register
1. Register 2. Connector Specifications Model
PC78MR-6
System
Resistance ( )
For TVC-EPC valve of hydraulic pump
30
For right boom swing stop EPC valve For left boom swing stop EPC valve
5
Function • When the emergency pump drive switch is turned ON, this resistor is used to supply a proper current to EPC valve according to the condition of the work equipment. a Current does not flow under the normal condition.
PC78MR-6
10-151
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SYSTEM COMPONENTS
PPC oil pressure switch
1. Plug 2. Switch 3. Connector Specifications Contact composition: N.O. contact Operation (ON) pressure: 490 ± 98.1 kPa {5.0 ± 1.0 kg/cm2} Reset (OFF) pressure: 294 ± 49.0 kPa {3.0 ± 0.5 kg/cm2} Function • The control valve has 5 PPC oil pressure switches, which sense the operating condition of each actuator from the PPC pressure and send it to the controller.
10-152
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SYSTEM COMPONENTS
Overload alarm pressure switch (For EU spec.)
1. Plug 2. Sensor 3. Connector Function • One pressure switch is installed to the boom cylinder bottom circuit to sense the hydraulic pressure on the boom cylinder bottom side.
PC78MR-6
10-152-1 (1)
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SYSTEM COMPONENTS
Engine speed sensor a See SENSOR.
TVC-EPC valve a See HYDRAULIC PUMP.
PPC lock solenoid valve 2-stage travel speed selector solenoid valve
Swing holding brake solenoid valve Left boom swing stop EPC valve Right boom swing stop EPC valve a See EPC SOLENOID VALVE.
Monitor panel a See MONITOR SYSTEM
PC78MR-6
10-153
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
MONITOR SYSTEM
MONITOR SYSTEM
1. 2. 3. 4. 5.
Monitor panel Battery Controller Sensors and switches Wiper motor, windshield washer motor
Outline • The monitor system monitors the machine condition by the sensors installed to various parts of the machine and processes and displays it on the panel immediately to notify the operator of the condition of the machine.
Input and output signals a. Power source b. Switch signal c. Caution signal d. Sensor, switch signal e. Sensor, switch signal f. Drive output
10-154
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
MONITOR SYSTEM
MONITOR PANEL
Outline • The monitor panel has the monitor display function, gauge display function, service meter function, electric system display function, and alarm buzzer. • The monitor panel has a CPU (Center Processing Unit) in it to display and output information. • The monitor switch unit consists of 3 flat sheet switches. Each time those switches are pressed, the displayed machine condition changes. The currently displayed condition is indicated by the LED at the top of the switches. • If there is any trouble in the monitor panel, controller, or wiring between monitor panel and controller, the monitor does not display information correctly. AMP040-20P [CN-P02] Input and output signals Input/ Pin AMP070-12P [CN-P01] Signal name Output Pin No. 1 2 3 4 5 6 7 8 9 10 11 12
Signal name Starting switch (Battery) Starting switch (Battery) Windshield washer motor output Starting switch (Terminal C) Wiper W contact GND GND VB+ (24 V) Wiper motor (+) Wiper motor (-) Alarm buzzer ON signal Wiper P contact
PC78MR-6
Input/ Output signal Input Input Output Input Input – – Input Output Output Input Input
No. 1 2 3 4 5 6 7 8
Engine coolant temperature Fuel level Radiator water level NC Air cleaner clogged NC Engine oil pressure Engine oil level
9
S-NET signal
10
S-NET signal
11 12 13 14 15 16 17 18 19 20
Charge level NC GND (Analog signal) NC Pull-up window limit switch Alarm buzzer cancel Swing lock Preheating Lamp switch GND (S-NET)
signal Input Input Input Input Input Input Input Input Input/ Output Input/ Output Input – – – Input Input Input Input Input –
10-155
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
MONITOR SYSTEM
METER DISPLAY UNIT (FOR STD SPEC.)
No. Display type 1
Display range
Display method
Service meter
0-99999.9 h
Time is measured while engine is running (alternator is generating) (Lamp always lights up even if starting switch is at OFF position.)
Display
3 alphanumerics 0 – 99.9 V
[*1] 2
3a
Display item
Gauge
3b
Monitor
4a
Gauge
Coolant temperature
Fuel level 4b
Monitor
5
See above drawing. Above set temperature (99°C) See above drawing. Below set level (30 liters)
Preheating
During preheating
One-touch deceleration
When one-touch decelerator operates
Charge level
When charging is defective (charge voltage < battery voltate)
Pilot 6
7 Caution
Engine oil pressurre
8
• If electric control system has trouble, 3 alphanumerics (user code, service code) is displayed. • Voltage of boom swing potentiometer is displayed. Segment of corresponding level and all segments below it light up. [Monitor lamp blinks when 8th level lights up (above 99°C). Monitor lamp blinks and alarm buzzer sounds when 9th level lights up.] Segment of corresponding level and all segments below it light up. [Monitor lamp blinks and alarm buzzer sounds when 1st level lights up (below 30 liters).] Lamp lights up for about 30 seconds when starting switch is turned to HEAT position, then blinks (for about 10 seconds) to show that preheating is finished and then goes off.
Display color
Remarks
Blue
LCD
Red
LED
Blue
LCD
Red
LED
Green
Lamp lights up when one-touch decelerator operates.
Lamp lights up when starting switch is turned to ON position and goes off after engine starts. Lamp is turned off when normal and on when abnormal. Below set pressure (If trouble occurs while engine is running, (49 kPa {0.5 kg/ buzzer sounds.) cm2})
Lamp
Red
*1: For the display method of the marked items, see ELECTRIC CONTROL SYSTEM.
10-156 (1)
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
MONITOR SYSTEM
METER DISPLAY UNIT (FOR EU SPEC.)
No. Display type
Display item
Display range
Display method Time is measured while engine is running (alternator is generating) (Lamp always lights up even if starting switch is at OFF position.)
1
Service meter
0-99999.9 h
[*1] 2
Display
3 alphanumerics
3a
Gauge
3b
Monitor
4a
Gauge
Coolant temperature
Fuel level 4b
Monitor
5
See above drawing. Above set temperature (99°C) See above drawing. Below set level (30 liters)
Preheating
During preheating
6
One-touch deceleration
When one-touch decelerator operates
7
Overload
Below set pressure (12.7 MPa {130 kg/ cm2})
Pilot
8
Caution
9
Charge level
When charging is defective (charge voltage < battery voltate)
Engine oil pressurre
Below set pressure (49 kPa {0.5 kg/ cm2})
If electric control system has trouble, 3 alphanumerics (user code, service code) is displayed. In depth 0 set mode, depth from datum plane is displayed. Segment of corresponding level and all segments below it light up. [Monitor lamp blinks when 8th level lights up (above 99°C). Monitor lamp blinks and alarm buzzer sounds when 9th level lights up.] Segment of corresponding level and all segments below it light up. [Monitor lamp blinks and alarm buzzer sounds when 1st level lights up (below 30 liters).] Lamp lights up for about 30 seconds when starting switch is turned to HEAT position, then blinks (for about 10 seconds) to show that preheating is finished and then goes off.
Display color
Remarks
Blue
LCD
Red
LED
Blue
LCD
Red
LED
Green
Lamp lights up when one-touch decelerator operates. Lamp Lamp lights up when starting switch is turned to ON position and goes off after engine starts. Lamp is turned off when normal and on when abnormal. (If trouble occurs while engine is running, buzzer sounds.)
Red
*1: For the display method of the marked items, see ELECTRIC CONTROL SYSTEM.
PC78MR-6
10-156-1 (1)
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
MONITOR SYSTEM
MONITOR SWITCH UNIT
No. Name 1
2
3
4
Function
Operation
Travel speed selector switch
Switch used to select 1 of 2 travel speeds When Lo lamp is ON: Low travel speed When Hi lamp is ON: High travel speed
Working mode selector switch
Switch used to set movement and power of work equipment When E lamp is OFF: Active mode (For heavy load work) When E lamp is ON: E mode (For work in which fuel consumption is more important)
Active (OFF) io E (Lamp OFF)
Wiper switch
Switch used to operate front glass wiper When ON lamp is ON: Wiper operates continuously. When INT lamp is ON: Wiper operates intermittently. When all lamps are OFF: Wiper is stopped.
OFF (Lamp OFF) o INT (Intermittent) o ON (Continuous)
Switch used to spout washing liquid over front glass
[When wiper is stopped] ON: Washing liquid spouts and wiper operates continuously. OFF:After switch is released, wiper operates by 2 cycles continuously and then stops. [When wiper is operating intermittently] ON: Washing liquid spouts and wiper operates continuously. OFF:After switch is released, wiper operates for 2 cycles continuously and then starts intermittent operation again.
Windshield washer switch
Lo io Hi
a The boldfaced letters in the operation column denote the position to which each switch is reset when the starting switch is turned to the "ON" position.
PC78MR-6
10-157
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SENSORS
SENSORS • • •
The signals from the sensors are input directly to the panel or controller. The sensors are classified into 3 of contact type, resistance type, and electromagnetic type. Either of each sensor of contact type must be connected to the chassis ground. Type of display
Type of sensor
Sensing method
When normal
When abnormal
Caution
Engine oil pressure
Contact
OFF (Open)
ON (Closed)
Coolant temperature
Resistance
–
–
Fuel level
Resistance
–
–
Engine speed
Electromagnetic
–
–
Gauge –
Engine oil pressure sensor
1. Plug 2. Contact ring
3. Contact 4. Diaphragm
5. Spring 6. Terminal
Function • This sensor is installed to the engine cylinder block to sense oil pressure with diaphragm (4). If the oil pressure lowers below the set level, the switch is turned on and the signal is sent to the monitor panel.
Coolant temperature sensor
1. Connector
2. Plug
3. Thermistor
Function • This sensor is installed to the engine cylinder block. It senses changes of temperature by changes of the resistance of thermistor (3) and sends the change signals to the monitor panel.
10-158 (1)
PC78MR-6
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SENSORS
Fuel level sensor
1. Float 2. Arm
3. Connector 4. Variable resistor
Function • This sensor is installed to the fuel tank and its float (1) moves up and down according to the fuel level. Float (1) operates variable resistor (4) through arm (2) and sends the signals to the monitor panel.
PC78MR-6
10-159 (1)
STRUCTURE, FUNCTION AND MAINTENANCE STANDARD
SENSORS
Engine speed sensor
Wire Magnet Terminal
Housing Connector
Function This sensor is installed to the engine flywheel cover. It counts the number of teeth which pass in front of it and sends the signals to the controller. Reference: Number of teeth of ring gear: 110
10-160 (1)
PC78MR-6
20 TESTING AND ADJUSTING STANDARD VALUE TABLE ........................... 20- 2 Standard value table for engine .................. 20- 2 Standard value table for chassis ................. 20- 3 Standard value table for electrical parts .......20- 11 TESTING AND ADJUSTING.......................... 20-101 TROUBLESHOOTING ................................... 20-201
a Note the following when making judgements using the standard value tables for testing, adjusting, or troubleshooting. 1. The standard value for a new machine given in the table is the value used when shipping the machine from the factory and is given for reference. It is used as a guideline for judging the progress of wear after the machine has been operated, and as a reference value when carrying out repairs. 2. The service limit value given in the tables is the estimated value for the shipped machine based on the results of various tests. It is used for reference together with the state of repair and the history of operation to judge if there is a failure. 3. These standard values are not the standards used in dealing with claims. When carrying out testing, adjusting, or troubleshooting, park the machine on level ground, insert the safety pins, and use blocks to prevent the machine from moving. When carrying out work together with other workers, always use signals and do not let unauthorized people near the machine. When checking the water level, always wait for the water to cool down. If the radiator cap is removed when the water is still hot, the water will spurt out and cause burns. Be carught in the fan, fan belt or other rotating parts.
PC78MR-6
20-1
TESTING AND ADJUSTING
STANDARD VALUE TABLE FOR ENGINE
STANDARD VALUE TABLE FOR ENGINE
Item
Machine Model
PC78MR-6
Engine
S4D95LE-3
Measurement Conditions
Unit
High idling (When mounted on machine) Revolving speed
Low idling (When mounted on machine)
Standard Value for New Machine
Service Limit Value
2,020 ± 50
—
rpm
Rated revolving speed
— 1,850
—
Bosch Index
Max. 3.5 Max. 1.0
6.0 2.0
mm
0.35 0.50
— —
Exhaust gas color
At sudden acceleration At high idling
Valve clearance (At normal temperature)
Air intake valve Exhaust valve
Compression pressure (SAE15W-40 oil)
Oil temperature: 40 – 60 °C (Engine speed)
MPa {kg/cm2} (rpm)
Min. 2.94 {Min. 30} 320 – 360
2.06 {21} —
Blow-by pressure (SAE30 oil)
(Water temperature operating range) At rated output
Pa {mmH2O}
Max. 490 {50} reference value
980 {100} reference value
0.34 – 0.54 {3.5 – 5.5}
0.25 {2.5}
0.29 – 0.49 {3.0 – 5.0}
0.21 {2.1}
(SAE30)
Min. 0.18 {Min. 1.8}
0.15 {1.5}
(SAE10W)
Min. 0.15 {Min. 1.5}
0.13 {1.3}
°C
90 – 110
120
° (Deg.)
5 ± 0.75
5 ± 0.75
6 – 10
6 – 10
6 – 10
6 – 10
(Water temperature operating range) (SAE30) At high idling (SAE10W)
Oil pressure
MPa {kg/cm2}
At low idling
Oil temperature
All revolution range (In oil pan)
Fuel injection timing
Before compression top dead center
Tension of fan belt
Deflection under finger pressure of approx. 58.8 N {6 kg}
mm
Tension of air compressor belt
20-2
Deflection under finger pressure of approx. 58.8 N {6 kg}
PC78MR-6
TESTING AND ADJUSTING
STANDARD VALUE TABLE FOR CHASSIS
STANDARD VALUE TABLE FOR CHASSIS Machine Model
Stroke of control lever, pedal stroke
Engine speed
Category
Item
At relief of 1 pump
Measurement Conditions • • •
Hydraulic oil temperature: 45 – 55 °C Engine water temperature: Within operating range Relief of 1 pump....Arm DUMP relief
Unit
Standard Value for New Machine
Service Limit Value
rpm
Min. 1,800
Min. 1,800
Boom control lever
N o RAISE, LOWER
85 ± 10
Max. 95 Min. 75
Arm control lever
N o IN, OUT
85 ± 10
Max. 95 Min. 75
Bucket control lever
N o CURL, DUMP
85 ± 10
Max. 95 Min. 75
N o LEFT, RIGHT
85 ± 10
Max. 95 Min. 75
21 ± 2
Max. 23 Min. 19
53 ± 6
Max. 59 Min. 47 Max. 127 Min. 103
Swing control lever
•
Boom swing control pedal
• •
Blade control lever
•
Center of lever grip End of pedal Read Max. value through stroke end Stop engine
N o LEFT, RIGHT
mm
N o RAISE, LOWER
Travel control lever
N o FORWARD, REVERSE
115 ± 12
Attachment control pedal
N o FORWARD, REVERSE
Forward 37 Reverse 23
Forward Max. Min. Reverse Max. Min.
Play of control lever
Max. 10
Max. 15
Boom control lever
15.7 ± 3.9 {1.6 ± 0.4}
Max. 24.5 {Max. 2.5}
Arm control lever
15.7 ± 3.9 {1.6 ± 0.4}
Max. 24.5 {Max. 2.5}
12.7 ± 2.9 {1.3 ± 0.3}
Max. 21.6 {Max. 2.2}
12.7 ± 2.9 {1.3 ± 0.3}
Max. 21.6 {Max. 2.2}
78.4 ± 19.6 {8.0 ± 2}
Max. 117.7 {Max. 12}
Blade control lever
25.5 ± 6.9 {2.6 ± 0.7}
Max. 39.2 {Max. 4.0}
Attachment control pedal
Forward 22.5±4.9 {2.3±0.5} Reverse 36.3±4.9 {3.7±0.5}
Bucket control lever Operating effort of control lever
PC78MR-6
Swing control lever Boom swing control pedal
•
• • •
Measure operating effort of each control lever by installing push-pull scale to center of its grip. Measure operating effort of each control pedal by installing push-pull scale to its end. Read Max. value through stroke end. Stop engine.
N {kg}
39 35 25 21
Forward Max. 31.0 {Max. 3.2} Reverse Max. 50.9 {Max. 5.2}
Lever
24.5 ± 5.9 {2.5 ± 0.6}
Max. 39.2 {Max. 4.0}
Pedal
74.5 ± 18.6 {7.6 ± 1.9}
Max. 107.6 {Max. 11}
Travel control lever
PC78MR-6
20-3
TESTING AND ADJUSTING
STANDARD VALUE TABLE FOR CHASSIS
Machine Model
Standard Value for New Machine
Service Limit Value
Boom
26.5 ± 0.98 {270 ± 10}
26.5 ± 1.47 {270 ± 15}
Arm
26.5 ± 0.98 {270 ± 10}
26.5 ± 1.47 {270 ± 15}
Bucket
26.5 ± 0.98 {270 ± 10}
26.5 ± 1.47 {270 ± 15}
Boom swing
26.5 ± 0.98 {270 ± 10}
26.5 ± 1.47 {270 ± 15}
20.5 ± 0.98 {210 ± 10}
20.5 ± 1.47 {210 ± 15}
12.74 + 01.95 {130 ± 15}
12.74 ± 1.47 {130 ± 15}
21.08 ± 0.98 {215 ± 10}
21.08 ± 1.47 {215 ± 15}
26.5 ± 0.98 {270 ± 10}
26.5 ± 1.47 {270 ± 15}
3.14 + 00.2
3.14 + 0.3 0
{32 + 02 }
{32 + 03 }
Max. 20
Max. 20
deg (mm)
40 ± 10 {297 ± 74}
Max. 60 {Max. 446}
sec
2.2 ± 0.3 {2.6 ± 0.3}
Max. 2.8 {Max. 3.2}
3.7 ± 0.3 {4.1 ± 0.3}
Max. 4.3 {Max. 4.7}
Category
Item
Swing Oil pressure
PC78MR-6
Measurement Conditions
• •
Hydraulic oil temperature: 45 – 55 °C Relief pressure with engine at full throttle (Relieve only circuit to be measured)
Unit
With blade RAISE
Blade
MPa {kg/cm2}
LOWER Travel
Control
Lowering of oil pressure
• •
Hydraulic oil temperature: 45 – 55 °C Difference between relief pressure at Max. engine speed and relief pressure at 1/2 of rated engine speed (Pressure at relief of 1 pump)
Position of work equipmentMax. Reach
Overrun of swing
• • • Swing
•
Run engine a full throttle Hydraulic oil temperature: 45 – 55 °C Deviation of swing circle made when it stops after swinging 1 turn Value in { } is deviation of periphery of swing circle
90°
Time required to start swinging • • • •
20-4
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Time required to swing 90° and 180° from starting point Value in { } is measured under rated bucket load
180°
PC78MR-6
TESTING AND ADJUSTING
STANDARD VALUE TABLE FOR CHASSIS
Machine Model Category
Item
PC78MR-6
Unit
Standard Value for New Machine
Service Limit Value
sec
30 ± 2
Max. 35
mm (deg)
0 (0)
0 (0)
/ min.
Max. 3.5
Max. 7.0
Low speed
34 ± 3
41
High speed
25 ± 3 {23 ± 2}
30 {28}
Low speed
26 ± 2 {25 ± 2}
28 {20}
High speed
17 ± 2 {15.5 ± 2}
21 {19.5}
Measurement Conditions
Position of work equipment
Max. Reach
Time required to finish swinging
• • •
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Time required to swing 5 turns after swinging 1 turn
Swing
Position of work equipment: Extend to Max. reach with bucket under rated load or filled with dirt and sand (Rated load: 450 kg)
Hydraulic drift of swing
Leakage from swing motor
• • • • •
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Swing upper structure to 45° on slope of 15° Make match marks on swing circle outer race and track frame Measure deviation of marks made in 15 minutes
• • •
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Relieve swing circle
Position of work equipment
Travel speed (1) • • • Travel
•
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Raise either track and measure time required to move 5 turns after finishing 1 turn. { }: Rubber shoe specification
sec
Position of work equipment
Travel speed (2)
• • • •
PC78MR-6
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Measure time required to travel 20 m after run-up of at least 10 m on flat surface { }: Rubber shoe specification
20-5
TESTING AND ADJUSTING
STANDARD VALUE TABLE FOR CHASSIS
Machine Model Category
Item
Measurement Conditions
PC78MR-6
Unit
Standard Value for New Machine
Service Limit Value
mm
Max. 300
330
cc/min.
Max. 10
Max. 50
mm
0
0
Max. 4.5
Max. 7.0
Position for measurement
Travel deviation
• • •
Travel
•
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Measure deviation made during travel of 20 m after run-up of at least 10 m on flat surface Measure on firm and level place
a Measure distance x Leakage from swivel joint (Each port)
• •
Hydraulic oil temperature: 45 – 55 °C Apply relief pressure to port to be measured
Position for measurement
Hydraulic drift of travel
Leakage from travel motor
20-6
• • • •
Stop engine Hydraulic oil temperature: 45 – 55 °C Stop machine on slope of 30° with sprocket up Measure hydraulic drift of travel made in 5 minutes
• • •
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Lock shoes and relieve travel circuit
/min.
PC78MR-6
TESTING AND ADJUSTING
STANDARD VALUE TABLE FOR CHASSIS
Machine Model Category
Item
Whole work equipment (Hydraulic drift of bucket tooth tip)
PC78MR-6
Measurement Conditions
Unit
Hydraulic drift
• • • • • • • •
Measure extension and retraction of each cylinder and hydraulic drift of bucket tooth tip from above position Measure on level and flat surface Bucket: Apply rated load of 4,413 N {450 kg} Set lever in neutral Stop engine Hydraulic oil temperature: 45 – 55 °C Start measurement just after setting Measure hydraulic drift every 5 minutes and judge after 15 minutes
Blade (Hydraulic drift of blade tip
• • •
Stop engine Hydraulic oil temperature: 45 – 55 °C Measure hydraulic drift of blade tip from Max. height in 15 minutes
Leakage from cylinder (Each cylinder)
• •
Hydraulic oil temperature: 45 – 55 °C Apply relief pressure to cylinder to be measured
Max. 350
Max. 600
Max. 8
Max. 12
mm
Max. 41
Max. 62
Max. 25
Max. 38
Max. 20
Max. 30
cc/min.
Max. 1.5
Max. 7.5
3.2 ± 0.3
Max. 4
Position for measurement Boom Bucket tooth on ground
Work equipment speed
Work equipment
Bucket cylinder (Retraction of cylinder)
Service Limit Value
Position for measurement
Boom cylinder (Retraction of cylinder)
Arm cylinder (Extension of cylinder)
Standard Value for New Machine
Max. extension of cylinder
(To just before (To just before cushion) cushion)
LOWER • •
Arm Max. retraction of cylinder
• •
3.1 ± 0.3
Max. 3.7
3.3 ± 0.3
Max. 4.1
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C sec
Position for measurement
Max. extension of cylinder
PC78MR-6
RAISE
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C
IN
(To just before (To just before cushion) cushion)
DUMP
(To just before (To just before cushion) cushion)
2.9 ± 0.3
Max. 3.5
20-7
TESTING AND ADJUSTING
STANDARD VALUE TABLE FOR CHASSIS
Machine Model Category
Item
PC78MR-6 Standard Value for New Machine
Service Limit Value
CURL
3.2 ± 0.4
Max. 4.0
DUMP
2.3 ± 0.3
Max. 3.1
Swing (R.H.)
6.7 ± 0.4
Max. 7.6
Swing (L.H.)
4.5 ± 0.4
Max. 5.3
Measurement Conditions
Unit
Position for measurement Bucket Max. retraction of cylinder
Max. extension of cylinder
• •
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C
Work equipment
Work equipment speed
Position for measurement Boom swing Swing (R.H.)
Swing (L.H.) • •
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C
Position for measurement sec Blade Blade on ground
RAISE
1.3 ± 0.3
Max. 2.1
Max. height of blade
LOWER
1.3 ± 0.3
Max. 2.1
Max. 2
Max. 3.9
• •
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C
Time lag
Position for measurement
Boom • • •
20-8
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Retract arm and bucket cylinder fully and lower boom from Max. height. Measure time from when bucket touches ground until when machine body rises.
PC78MR-6
TESTING AND ADJUSTING
STANDARD VALUE TABLE FOR CHASSIS
Machine Model Category
Item
Measurement Conditions
PC78MR-6 Unit
Standard Value for New Machine
Service Limit Value
0
Max. 1.0
0
Max. 1.0
Max. 1.0
Max. 2.0
See following pages
See following pages
Position for measurement
Arm
• • •
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Set upside of boom level and retract bucket cylinder fully. Extend bucket cylinder and measure time from when arm stops on lower side until when arm starts moving again.
sec
Bucket
Work equipment
Time lag
Position for measurement
• • •
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Set upside of boom level and retract bucket cylinder fully. Extend bucket cylinder and measure time from when arm stops on lower side until when arm starts moving again.
Position for measurement
Blade
Discharge of hydraulic pump
• • •
PC78MR-6
Piston pump
Run engine at full throttle Hydraulic oil temperature: 45 – 55 °C Lower blade from Max. height and measure time from when blade touches ground until when machine body rises.
See following pages
/min.
20-9
TESTING AND ADJUSTING
PC78MR-6 (With blade) Main pump discharge
Performance of hydraulic pump
Category
STANDARD VALUE TABLE FOR CHASSIS
•
Rated pump speed: 1,850 rpm Checkpoint
Discharge pressure of test pump (MPa {kg/cm2})
Average pressure (MPa {kg/cm2})
Standard discharge ( /min.)
Lower limit of criterion ( /min.)
Any
P1 (P2)
P1 (P2)
See graph
See graph
a Avoid measuring near a bend of the graph since the error is large there. a When measuring without removing the pump from the machine, if the engine speed cannot be set to the specified level with the fuel control dial, calculate the pump discharge pressure at the specified speed from the actual engine speed and measured pump discharge.
20-10
PC78MR-6
TESTING AND ADJUSTING
STANDARD VALUE TABLE FOR ELECTRIC PARTS
STANDARD VALUE TABLE FOR ELECTRIC PARTS Sys tem
Component Name
Connector No.
Inspection Method
Measurement Conditions
Criteria
Source voltage
M97
Measurement voltage
If the condition is within the range shown in the table below, it is normal. Between (1), (11) – chassis ground
20 – 30 V
Since power is constantly supplied, voltage is detected even if starting switch is turned OFF. Between (2), (12) , (22) – chassis ground
1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON.
20 – 30 V
If the condition is within the range shown in the table below, it is normal.
Swing LEFT stop solenoid
Potentio powersource
When safety lock lever is at FREE When safety lock lever is at LOCK
20 – 28 V
20 – 30 V M13 Between (1) – (2)
1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON.
Max. 0 V
If the condition is within the range shown in the table below, it is normal. M97
M97
M95
Measurement of current
Controller
Swing RIGHT stop solenoid
M97 M13
Between (15) – (23)
940 ± 50 mmA
If the condition is within the range shown in the table below, it is normal. Between (5) – (23)
Measurement of voltage
PPC main pressure lock solenoid
Measurement voltage
Between M97 (38) – (13)
1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON. 4) Exclude part near swing stroke end.
940 ± 50 mmA
If the condition is within the range shown in the table below, it is normal. Between (22) – (21)
5 ± 0.5 V
1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON.
Boom RAISE pressure switch
PC78MR-6
M95 M96
M95
Measurement of voltage
Model selection
Measurement of voltage
If the condition is within the range shown in the table below, it is normal. Model
PC78MR-6
Between M96 (37) – M95 (10)
Max. 1 V
Between M96 (27) – M95 (10)
Min. 7 V
Between M96 (7) – M95 (10)
Max. 1 V
Between M96 (30) – M95 (10)
Max. 1 V
1) Turn starting switch OFF. 2) Insert T-adapter. 3) Turn starting switch ON.
If the condition is within the range shown in the table below, it is normal When boom is raised When in neutral
Between M95 (12) – chassis ground
Max. 1V 5 ± 0.5 V
1) Turn starting switch OFF.. 2) Insert T-adapter. 3) Turn starting switch ON.
20-11
TESTING AND ADJUSTING
System
Component Name
Connector No.
STANDARD VALUE TABLE FOR ELECTRIC PARTS
Inspection Method
Measurement Conditions
Criteria
Swing, arm IN, travel pressure switch
M95
Measurement of voltage
If the condition is within the range shown in the table below, it is normalTurn starting switch OFF. When machine swings When arm is moved IN When machine travels
When in neutral
Between (24) - chassis ground Between (6) - chassis ground Between (18) - chassis ground
Max. 1 V
Max. 1 V
Boom swing angle potentiometer signal
M95
Measurement of voltage
If the condition is within the range shown in the table below, it is normal Between (8) – (21)
3.8 – 4.8 V
Swing holding brake clear solenoid
M97
Measurement of resistance
Controller
If the condition is within the range shown in the table below, it is normal When swing holding brake clear switch is OFF (When normal) When swing holding brake clear switch is ON (When cleared)
20 – 30 V Between (7) – (13) Max. 1 V
1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON.
1) Turn starting switch OFF. 2) Insert Tadapter. 3) Turn starting switch ON. 4) Move right swing to stroke end.
1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter. 4) Turn starting switch ON. 5) Swing or move arm in.
Left swing stop EPC solenoid
20-12
M12 (Male)
M11 (Male)
Measurement of resistance
Right swing stop EPC solenoid
M101 (Male)
Measurement of resistance
Swing angle potentiometer
Measurement of resistance
If the condition is within the range shown in the table below, it is normal Between (C) – (B)
0.2 – 7 kz
Between (B) – (A)
0.2 – 7 kz
Between (C) – (A)
4 – 6 kz
If the condition is within the range shown in the table below, it is normal Between M12 (male) (1) – (2) Between M12 (male) (1), (2) – chassis ground
5 – 25 z Min. 1 Mz
If the condition is within the range shown in the table below, it is normal Between M11 (male) (1) – (2) Between M11 (male) (1), (2) – chassis ground
5 – 25 z Min. 1 Mz
1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter.
1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter.
1) Turn starting switch OFF. 2) Disconnect connector. 3) Insert Tadapter.
PC78MR-6
TESTING AND ADJUSTING
Machine control
Swing holding brake reset solenoid
2nd travel speed selection solenoid
Inspection Method
M13 (Male)
M14 (Male)
M15 (Male)
Measurement of resistance
PPC main pressure lock solenoid
Connector No.
Measurement of resistance
Component Name
Measurement of resistance
System
STANDARD VALUE TABLE FOR ELECTRIC PARTS
Measurement Conditions
Criteria If the condition is within the range shown in the table below, it is normal. Between M13 (Male) (1) – (2)
35 – 80 z
Between M13 (Male) (1), (2) – chassis ground
Min. 1 Mz
If the condition is within the range shown in the table below, it is normal. Between M14 (Male) (1) – (2)
35 – 80 z
Between M14 (Male) (1), (2) – chassis ground
Min. 1 Mz
If the condition is within the range shown in the table below, it is normal. Between M15 (Male) (1) – (2)
35 – 80 z
Between M15 (Male) (1), (2) – chassis ground
Min. 1 Mz
1) Turn starting switch OFF. 2) Disconnect adapter. 3) Connect Tadapter.
1) Turn starting switch OFF. 2) Disconnect adapter. 3) Connect Tadapter.
1) Turn starting switch OFF. 2) Disconnect adapter. 3) Connect Tadapter.
If the monitor panel displays as shown in Tables 1 and 2, it is normal. Table 1 (Check and caution section).
Machine monitor system
Monitored Item (Input connector)
Engine oil pressure P02 (7)
Measurement Conditions
Preheater P02 (18)
PC78MR-6
Sensor Input Signal
Light is ON.
Max. 1 V
Light is OFF.
20 – 30 V
Light is ON.
Max. 5 V
Light is OFF.
20 – 30 V
Light is ON.
20 – 30 V
Light is OFF.
Max. 1 V
Start engine.
Check and caution section Charge level P02 (11)
Display
1) Connect Tadapter
Start engine.
Stop Engine.
20-13
TESTING AND ADJUSTING
Component Name
System
Connector No.
STANDARD VALUE TABLE FOR ELECTRIC PARTS
Inspection Method
Criteria
Measurement Conditions
Table 2 (Gauge)
Item indicated by gauge
Display level resistance (kz) (Monitor panel input resistance)
Turn starting switch ON
Turn starting switch OFF
1) Turn starting switch OFF and insert dummy resistor or measure resistance of sensor. 2) Turn starting switch ON and check indication.
Min. – Max. Upper side
I Measurement of resistance of coolant temperature gauge P02 (1) – (13)
Position of indication
Machine monitor system
O
Lower side Gauge section
9
4.00 – 3.45
8
3.13 – 3.75
7
3.39 – 3.94
6
3.56 – 4.39
5
3.97 – 5.18
4
4.68 – 6.89
3
6.23 – 10.88
2
10.34 – 36.86
1
33.35 – 37.83
a Blink at levels 8 and 9.
Item indicated by gauge
Display level resistance (z) (Monitor panel input resistance)
Turn starting switch ON
Turn starting switch OFF
1) Turn starting switch OFF and insert dummy resistor or measure resistance of sensor. 2) Turn starting switch ON and check indication.
Min. – Max. Upper side
I Measurement of resistance of fuel level gauge P02 (2) – (13)
Position of indication
O
Lower side
9
10 – 6.8
8
6.2 – 13.7
7
12.4 – 22.1
6
20.0 – 30.5
5
27.6 – 41.0
4
37.1 – 54.6
3
49.4 – 77.7
2
70.3 – 101.9
1
92.2 – 10
a Level 1 blinks.
20-14
PC78MR-6
TESTING AND ADJUSTING
Fuel level sensor
Alternator
PC78MR-6
Check of continuity
Measurement Conditions
Criteria If the condition is within the range shown in the table below, it is normal.
Between terminal – chassis ground
Normal engine oil pressure
No continuity
Low engine oil pressure
Normal continuity
If the condition is within the range shown in the table below, it is normal.
If the condition is within the range shown in the table below, it is normal.
M9 (Male)
Between T4 (Terminal R) – chassis ground
M18 (Male)
Machine monitor system
Coolant temperature sensor
T6
Inspection Method
Measurement of resistance
Engine oil pressure sensor
Connector No.
Measurement of resistance
Component Name
Measurement of voltage
System
STANDARD VALUE TABLE FOR ELECTRIC PARTS
Between (1) – (2)
Between (1) – (2)
Normal temperature (25 °C)
Approx. 40 kz
105 °C
Approx. 3.3 kz
Full
2–5z
Empty
105 – 110 z
While engine is running (at 1/2 or more of full throttle) o 27.5 – 29.5 V If battery is deteriorated or temperature is low, voltage may not rise for a while after engine is started.
1) Start engine 2) Disconnect terminal
1) Turn starting switch OFF 2) Disconnect connector
1) Turn starting switch OFF 2) Disconnect connector
1) Start engine
20-15
TESTING AND ADJUSTING List of devices for testing, adjusting, & troubleshooting .............................................................................. 20-102 Measuring engine speed............................................................................................................................. 20-103 Measuring exhaust gas color ...................................................................................................................... 20-104 Adjusting valve clearance ........................................................................................................................... 20-105 Measuring compression pressure ............................................................................................................... 20-106 Measuring blow-by pressure ....................................................................................................................... 20-107 Testing and adjusting fuel injection timing................................................................................................... 20-108 Measuring engine oil pressure .................................................................................................................... 20-112 Adjusting engine stop solenoid ................................................................................................................... 20-113 Adjusting fuel control linkage ...................................................................................................................... 20-115 Adjusting engine speed sensor ................................................................................................................... 20-117 Testing and adjusting hydraulic pressure in work equipment, swing, and travel circuits............................. 20-118 Measuring LS differential pressure and adjusting LS valve ........................................................................ 20-121 Adjusting PC valve ...................................................................................................................................... 20-123 Testing TVC-EPC solenoid output pressure ............................................................................................... 20-123 Measuring control circuit pressure .............................................................................................................. 20-124 Measuring PPC valve output pressure ....................................................................................................... 20-125 Testing solenoid valve output pressure ....................................................................................................... 20-126 Adjusting work equipment valve and swing PPC valve .............................................................................. 20-128 Testing travel deviation ............................................................................................................................... 20-129 Testing parts which can cause hydraulic drift of work equipment ............................................................... 20-131 Measuring oil leakage from swing and travel motors .................................................................................. 20-132 Releasing residual pressure from hydraulic circuit ..................................................................................... 20-133 Testing clearance of swing circle bearing ................................................................................................... 20-134 Testing and adjusting track shoe tension .................................................................................................... 20-135 Bleeding air from hydraulic circuit ............................................................................................................... 20-136 Replacement procedure of potentiometers ................................................................................................. 20-138 Procedure for testing diode ......................................................................................................................... 20-139
PC78MR-6
20-101
TESTING AND ADJUSTING
LIST OF DEVICES FOR TESTING, ADJUSTING, & TROUBLESHOOTING
LIST OF DEVICES FOR TESTING, ADJUSTING, & TROUBLESHOOTING Items to Be Tested/Adjusted Engine speed
Symbol A
Water temperature and oil temperature
Part No.
Part Name
Remarks Digital indication
1
799-203-9000
Multi-tachometer
2
6210-81-4111
Gear box
—
799-101-1500
Digital thermometer
-50 – 1,200 °C
799-101-5002
Hydraulic tester kit
790-261-1203
B
Pressure gauge
2.5, 5.9, 39.2, 58.8 MPa {25, 60, 400, 600 kg/cm2}
Digital hydraulic tester
Pressure gauge
58.8 MPa {600 kg/cm2}
799-401-2320
Hydraulic gauge
Pressure gauge
1.0 MPa {10 kg/cm2}
799-101-5160
Nipple
PT1/8
799-101-5220
Nipple
10 mm P = 1.25
07002-11023
O-ring
—
799-401-2910
Nipple
(Both male and female) 9/16-18 UNF (Female: PT1/8)
02896-11008
O-ring
—
07043-00108
Nipple
PT1/8 (Hexagon hole)
5
799-401-2701
Differential pressure gauge
—
1
795-502-1590
Compression gauge
0 – 6.9 MPa {0 – 70 kg/cm2} • Kit No.: 795-502-1205
2
795-502-1370
Adapter
—
1
2
3 Oil pressure
C
4
Compression pressure
D
L: 60 – 2,000 rpm H: 60 – 19,999 rpm
Blow-by pressure
E
799-201-1504
Blow-by checker
0 – 4,900 Pa {0 – 500 mmH2O}
Valve clearance
F
Purchased
Filler gauge
—
1
790-201-9000
Handy smoke checker
2
Purchased
Smoke meter
Discoloration 0 – 70% (with standard color) (Discoloration % x 1/10 Bosch index)
Exhaust gas color
G
Operating effort
H
Purchased
Push-pull scale
—
Stroke and hydraulic drift
I
Purchased
Scale
—
Work equipment speed
J
Purchased
Stopwatch
—
790-601-9320
Box
24-pin
799-601-9310
Plate
Applicable to 40-pole connector
799-601-8000
Adapter assembly
Including 21-pin box
1 2 Troubleshooting for wiring harnesses and sensors
K 3
Fuel injection timing
20-102
O
799-601-7310
For SWP12
799-601-7050
For SWP6
799-601-7520
Adapter
12 for 070
799-601-7360
Relay 5P
799-601-7370
Relay 6P
799-601-9200
Adapter kit
—
2
795-102-2102
Spring pusher
—
3
Commercialy available
Dial guage
—
PC78MR-6
TESTING AND ADJUSTING
MEASURING ENGINE SPEED
MEASURING ENGINE SPEED 1. When measuring engine speed during operation a Measure the engine speed under the following condition. • Cooling water temperature: Within operating range • Hydraulic oil temperature: 45 – 55 °C 1) Remove clamp (1) of the high pressure injection pipe and install sensor [1] of multitachometer A to injection pipe (2).
2) Connect the wiring harness of sensor [1] to amplifier [2] and connect the output wiring harness of amplifier [2] to tachometer A1. 3) Start the engine and turn dial a of amplifier [2] so that the value indicated by tachometer A1 will be stabilized, then measure the following revolving speeds. i) Low idling speed and high idling speed Set the fuel control lever to the low idling and high idling positions and measure the revolving speeds at the respective positions. ii) Revolving speed when pump is relieved Relieve the pump and run engine at full throttle and measure its revolving speed.
PC78MR-6
2. When measuring engine speed during measurement of compression pressure 1) Remove the cover for setting the injection timing of the injection pump from the timing gear case and install gear box A2.
2) Install bracket [3] of multi-tachometer A1 to gear box A2 and connect the wiring harness to tachometer A1. 3) Revolve the engine with the starting motor according to the procedure for measuring compression pressure and measure the revolving speed.
20-103
TESTING AND ADJUSTING
MEASURING EXHAUST GAS COLOR
MEASURING EXHAUST GAS COLOR •
When an air source and a power source are not available in the field, use handy smoke checker G1. When recording formal data, etc., use smoke meter G2. a Before measuring the exhaust gas color, raise the cooling water temperature to the operating range.
6) Raise the engine speed sharply and press accelerator pedal [3] of tool G2 simultaneously to have the filter paper absorb the exhaust gas. 7) Place the stained filter paper on the unused filter paper (at least 10 pieces) in the filter paper holder and read the indicated value.
When installing and removing the measuring instrument, take care not to touch a hot part. 1. Measuring with handy smoke checker G1 1) Install a piece of filter paper to tool G1. 2) Insert the exhaust gas suction pipe in the exhaust pipe, then raise the engine speed sharply and operate the handle of tool G1 simultaneously to have the filter paper absorb the exhaust gas. 3) Remove the filter paper and compare it with the attached scale.
2. Measuring with smoke meter G2 1) Insert probe [1] of G2 in the outlet of the exhaust pipe and tighten the clip to secure the probe to the exhaust pipe. 2) Connect probe hose [2], cable of accelerator pedal [3], and air hose [4] to tool G2. a Set the supplied air pressure below 1.47 MPa {15 kg/cm²}. 3) Connect the power cable to an outlet of AC 100 V. a When connecting the power cable, check that the power switch of tool G2 is turned OFF. 4) Loosen cap nut [5] of the suction pump and fit the filter paper. a Fit the filter paper securely so that the exhaust gas will not leak. 5) Turn ON the power switch of tool G2.
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a The firing order of the engine is as follows • Firing order: 1 – 2 – 4 – 3 a The air intake valves and exhaust valves may be adjusted in the firing order by revolving the crankshaft forward by 180° (4 cylinders). a For the valve clearance, see TESTING AND ADJUSTING, Failure criteria table.
PC78MR-6
TESTING AND ADJUSTING
ADJUSTING VALVE CLEARANCE
ADJUSTING VALVE CLEARANCE Method of adjusting valve clearance 1. Remove the cylinder head cover. 2. Turn the crankshaft forward and bring cylinder No. 1 to the compression top dead center and match the TOP mark line of crank pulley (5) to pointer (6), watching the movement of the air intake valve of cylinder No. 4 (4 cylinders). a The air intake valve of cylinder No. 4 (4 cylinders) moves (opens) when cylinder No. 1 comes near the compression top dead center.
a Adjust the valve clearance according to the following procedure. Loosen locknut (8) of adjustment screw (7). Insert filler gauge A of the specified thickness between valve stem (6) and rocker arm (5) and adjust the valve clearance so that the filler gauge will move lightly.
5. Tighten the locknut to secure the adjustment screw. Locknut: 44 ± 5.0 Nm {4.5 ± 0.5 kgm} 3. Adjust the clearance of the valves marked with q in the valve arrangement shown below. 4. Turn the crankshaft forward by 1 turn and adjust the clearance on the valves marked with Q.
PC78MR-6
20-105
TESTING AND ADJUSTING
MEASURING COMPRESSION PRESSURE
MEASURING COMPRESSION PRESSURE When measuring the compression pressure, take care not to touch the exhaust manifold, etc. to burn yourself or the rotary parts such as the fan, fan belt, etc. to be caught in them. 1. Adjust the valve clearance accurately. For details, see Adjusting valve clearance. 2. Warm up the engine until the oil temperature is 40 – 60 °C. 3. Remove nozzle holder assembly (1) of the cylinder to be measured. 4. Install adapter D2 to the fitting part of the nozzle holder and connect pressure gauge D1.
6. Disconnect wiring harnesses (2) from the terminals of the engine stop solenoid. Revolve the engine with the starting motor and measure the compression pressure and engine speed at this time. a Read the pressure gauge when its pointer is stabilized. a When measuring the compression pressure, measure the engine speed, too, and check that it is in the range of the measurement conditions. a After measuring the compression pressure, install nozzle holder assembly (1). Nozzle holder mounting bolt: 39.2 – 49 Nm {4 – 5 kgm}
5. Set the multi-tachometer to the engine. a See Measuring engine speed.
20-106
PC78MR-6
TESTING AND ADJUSTING
MEASURING BLOW-BY PRESSURE
MEASURING BLOW-BY PRESSURE a Measure the blow-by pressure under the following condition. • Cooling water temperature: Within operating range • Hydraulic oil temperature: 40 – 60°C 1. Install the nozzle of blow-by checker E to blowby hose (2).
a Normally, the blow-by pressure should be measured while the engine is operated at the rated output. In the field, however, an approximate value can be obtained by relieving the hydraulic circuit. a If it is impossible to run the engine at the rated output or relieve the hydraulic circuit, measure while the engine is running at high idling. The value obtained in this case is about 80% of the blow-by pressure at the rated output. a The blow-by pressure may vary largely with the engine condition. If the measured value is judged abnormal, check for increase of oil consumption, bad exhaust gas color, deterioration of oil, high deterioration speed of oil, etc. which are related to the abnormal blowby pressure.
2. Connect the nozzle to the gauge by the hose. 3. Set the working mode in the ACTIVE mode, run the engine at full throttle, and relieve the arm dump circuit. 4. When the gauge pointer is stabilized, measure the blow-by pressure. Do not touch a hot part or a rotary part during measurement.
PC78MR-6
20-107
TESTING AND ADJUSTING
TESTING AND ADJUSTING FUEL INJECTION TIMING
TESTING AND ADJUSTING FUEL INJECTION TIMING Adjustment by use of match marks a Apply this method usually. (Then installing the fuel injection pump to the original engine without repairing it, when checking only the injection timing, etc.) 1. Bring cylinder No. 1 to the compression top dead center. 1) Turn the crankshaft forward and match 1.4Top line (1) on the crank pulley to pointer (2).
2) Check that cylinder No. 1 is at the compressi on top de ad ce nter by the fo ll owi ng method. If the following condition is not obtained, turn the crankshaft one more turn. a If the fuel injection pump is removed: Check that C is seen at the tooth tip of the idler gear. a If the fuel injection pump is installed to the engine: Remove the head cover and check that (both air intake valve and exhaust valve of cylinder No. 1 have the valve clearance).
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2. Remove front cover (3) of the fuel injection pump. 3. Install the fuel injection pump holder and drive gear as one unit to the engine. 4. Insert the timing check pin 4.0 – 4.5 mm in diameter and 80 mm in length on hole a of the front gear cover and match it to the hole of the drive gear. a Check that the timing check pin enters straight and the hole of the fuel injection pump holder is aligned with the mounting hole of the front gear cover (in which the mounting bolt will be inserted). a If the holes are deviated from each other, remove the fuel injection pump and check its engagement with the drive gear.
5. Remove the timing check pin and tighten each bolt.
PC78MR-6
TESTING AND ADJUSTING
Adjustment by delivery valve method (When installing a repaired or replaced fuel injection pump, when checking after disassembling or replacing the gear train)
TESTING AND ADJUSTING FUEL INJECTION TIMING
4. Using spring pusher O2, compress the valve spring and remove valve cotter (5). 5. Loosen spring pusher O2 and remove spring seat (6) and valve spring (7).
1. Remove the cylinder head cover. 2. Bring cylinder No. 1 to the compression top dead center. 1) Turn the crankshaft forward and match injection timing line (1) on the crank pulley to pointer (2). 2) Check that both air intake valve and exhaust valve of cylinder No. 1 have the valve clearance. a If either or both of the valves do not have the valve clearance, turn the crankshaft one more turn. 6. Turn the stem of air intake valve (8) with the fingers while it is in contact with the top of piston (9) to fit it securely.
3. Remove snap ring (3) from the front end of the rocker shaft, then remove air intake rocker arm (4) of cylinder No. 1.
PC78MR-6
20-109
TESTING AND ADJUSTING
TESTING AND ADJUSTING FUEL INJECTION TIMING
7. Apply dial gauge O3 to the valve stem end and turn the crankshaft forward or in reverse to set the dial gauge to 0 when its pointer starts turning in reverse. 8. Turn the crankshaft about 45 degrees in reverse from the compression top dead center of cylinder No. 1. 9. Turn the crankshaft forward so that the dial gauge indicates standard dimension a. Standard dimension BTDC °(Deg) a
mm
5 ± 0.75 0.3 ± 0.08 12. Set the fuel injection lever to the FULL position. 13. Loosen the nut at the oblong hole of the injection pump mounting flange, then loosen the injection pump mounting bolts (14).
10. Disconnect fuel injection pipe (10) of cylinder No. 1. 11. Remove delivery valve holder (11), and remove delivery valve (12) and spring (13) from its inside. Then, install delivery valve holder (11) again.
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14. Turning the injection pump outward and operating the priming pump, move the injection pump toward the cylinder block little by little and stop when the fuel stops flowing out of the delivery valve holder. a If the injection pump is slanted out, the injection timing is delayed. If the former is slanted toward the cylinder block, the latter is advanced. 15. Tighten injection pump mounting bolts (14) alternately. 16. Tighten the nut at the oblong hole of the injection pump mounting flange.
PC78MR-6
TESTING AND ADJUSTING
TESTING AND ADJUSTING FUEL INJECTION TIMING
17. Turn the crankshaft forward and check that the pointer of the dial gauge is in the standard range shown in the following table when cylinder No. 1 is at the top dead center (when the pointer of the dial gauge starts moving in reverse). If the pointer of the dial gauge is out of this range, repeat the above steps from 7. • Dimension when cylinder is at top dead center: 0 ± 0.08 mm 18. Remove the delivery valve holder (11) and install delivery valve (12) and spring (13) to it, then install delivery valve holder (14) again. a Replace the o-ring and copper gasket of the delivery valve. Tighten the delivery valve 3 times to secure it. (If it is not tightened sufficiently, the gasket may be broken.) Delivery valve holder: 39.2 – 44.1 Nm {4 – 4.5 kgm} 19. Connect fuel injection pipe (3). Sleeve nut: 19.6 – 24.5 Nm {2 – 2.5 kgm} 20. Install valve spring (7) and valve seat (6). 21. Compress the valve spring with spring pusher O2 and install valve cotter (5). 22. Install air intake rocker arm (4) of cylinder No. 1, then install snap ring (3). Install the snap ring securely. 23. Install the cylinder head cover. Sleeve nut: 7.84 – 9.8 Nm {0.8 – 1.0 kgm}
PC78MR-6
20-111
TESTING AND ADJUSTING
MEASURING ENGINE OIL PRESSURE
MEASURING ENGINE OIL PRESSURE a Measure the engine oil pressure under he following condition. • Cooling water temperature: Within operating range
3. Run the engine at low idling and high idling and measure the engine oil pressure at each speed.
1. Remove oil pressure pickup plug (1) (PT 1/8) from the engine block under the alternator.
2. Install oil pressure measuring nipple C3 and connect oil pressure gauge C2 (0.98 MPa {10 kg/ cm²}).
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PC78MR-6
TESTING AND ADJUSTING
ADJUSTING ENGINE STOP SOLENOID
ADJUSTING ENGINE STOP SOLENOID 1. Install ball joint (2) to solenoid (1) and tighten locknut (3). a a: Approx. 1mm (thread)
2. Install rod (4) and rod end (5) to ball joint (2) temporarily. a Screwing depth b of rod in ball joint: Approx. 12.5 mm a Screwing depth c of rod end in rod: Approx. 10.0 mm
PC78MR-6
3. Supply power to solenoid (1) to turn it on. a If stop lever (6) and rod end (5) of the fuel injection pump are connected before the solenoid is turned on, the solenoid cannot pull sufficiently (the operating current flows continuously) and the coil will burn. Accordingly, do not connect them at this time.
4. Check that solenoid (1) is turned on, then connect rod end (5) to stop lever (6) and adjust the length of rod (4) so that the stop lever will touch the lever end on the service side. a If solenoid (1) is connected to the power source without using the machine wiring, do not keep the PULL terminal cable connected. (If the PULL terminal cable is kept connected, the operating current flows continuously and the coil will burn.)
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TESTING AND ADJUSTING
a Stop lever (6) touches the lever end on the service side (inside the fuel injection pump). a Play: 0 mm
ADJUSTING ENGINE STOP SOLENOID
5. Tighten nut (7) of the joint of stop lever (6) and rod end (5) and insert the cotter pin. a Install the rod end with grease hole (8) up. Rod end: Grease (G2-LI)
6. Lengthen rod (4) to give play to the stop lever end on the service side. a Play d: 1.0 – 2.0 mm (loosen rod by 1/2 – 1 turn.)
a When adjusting the length of rod (4), do not apply force so strongly that stop lever (6) will be pulled up more than the lever end. a Adjust the length of the rod as shown below.
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PC78MR-6
TESTING AND ADJUSTING
7. Tighten locknut (8). a At this time, take care that rod (4) will not turn together with locknut (9). Do not twist stop lever (6) forcibly. 8. Start and stop the engine 2 – 3 times and check that solenoid (6) operates smoothly to stop the engine.
PC78MR-6
ADJUSTING ENGINE STOP SOLENOID, ADJUSTING FUEL CONTROL LINKAGE
ADJUSTING FUEL CONTROL LINKAGE 1. Adjusting control linkage 1) If any part was replaced, connect the cable to the fuel injection pump governor lever securely. a Connect the cable to the hole at the end of the injection pump governor lever. 2) Turn the starting switch to the ON position and set the fuel control dial to the FULL position. 3) Bring fuel injection pump governor lever (1) in contact with stopper (2) on the FULL side. 4) Under this condition, pull cable (3) with force of about 98 N {about 10 kg} and tighten nuts (4) and (5) temporarily. a Tighten the nuts while pulling the cable to eliminate play. 5) Return nut (4) by 2 turns and tighten nut (5) by 2 turns retighten them. 6) Start the engine and check that it runs at the specified speed.
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TESTING AND ADJUSTING
2. Adjusting control linkage finely If the control linkage cannot be adjusted by the method in 1. above, adjust it finely with the turnbuckle above the cable. • When the engine speed (high idling speed) is below the specified level 1) Turn the starting switch to the ON position and set the fuel control dial to the FULL position. 2) Loosen nut (6) (right-hand screw) and nut (7) (left-hand screw). 3) Turn bolt (8) counterclockwise, seeing from the governor lever side, to eliminate the clearance between injection pump governor lever (1) and full stopper (2). 4) Tighten nuts (6) and (7).
ADJUSTING FUEL CONTROL LINKAGE
4) Tighten nuts (6) and (7). Nut: 8.8 – 10.8 Nm {0.9 – 1.1 kgm} a At this time, check that clearance A and B between bolt (8) and nuts (6) and (7) are 5 ± 3.5 mm (1.5 – 8.5 mm). a At this time, check that the rubber boot (10) of the cable is not twisted. 5) Start the engine and check that it runs at the specified speed.
Nut: 8.8 – 10.8 Nm {0.9 – 1.1 kgm}
5) • 1) 2) 3)
a At this time, check that clearance A and B between bolt (8) and nuts (6) and (7) are 5 ± 3.5 mm (1.5 – 8.5 mm) respectively. a At this time, check that the rubber boot (10) of the cable is not twisted. Start the engine and check that it runs at the specified speed. When the engine speed (low idling speed) is above the specified speed. Turn the starting switch to the ON position and set the fuel control dial to the deceleration (SLOW) position. Loosen nut (6) (right-hand screw) and nut (7) (left-hand screw). Turn bolt (8) counterclockwise, seeing from the governor lever side, to lengthen the cable and eliminate the clearance between injection pump governor lever (1) and low idling stopper (9).
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PC78MR-6
TESTING AND ADJUSTING
ADJUSTING ENGINE SPEED SENSOR
ADJUSTING ENGINE SPEED SENSOR a Adjust the engine speed sensor for the pump controller according to the following procedure. a The engine G speed and engine Ne speed sensor for the engine controller cannot be adjusted. 1. Screw in sensor (1) until its tip touches the tooth tip of flywheel ring gear (2). a Before installing the sensor check that its tip is free from steel chips and flaws. Threads: Hydraulic sealant 2. Return sensor (1) by 1/2 – 2/3 turns. a A clearance of 0.75 – 1.00 mm is made between the sensor tip and gear tooth tip. 3. Secure sensor (1) with nut (3). Nut: 69 – 74 Nm {7.0 – 7.5 kgm}
PC78MR-6
20-117
TESTING AND ADJUSTING
TESTING AND ADJUSTING HYDRAULIC PRESSURE IN WORK EQUIPMENT, SWING, AND TRAVEL CIRCUITS
TESTING AND ADJUSTING HYDRAULIC PRESSURE IN WORK EQUIPMENT, SWING, AND TRAVEL CIRCUITS a Hydraulic oil temperature for measurement: 45 – 55 °C Lower the work equipment to the ground and stop the engine. Then, loosen the hydraulic oil filler cap slowly to release the internal pressure of the hydraulic tank. Set the safety valve lock lever to the LOCK position. Measuring hydraulic pressure in boom arm, bucket, travel, and swing circuits 1. Measuring 1) Installing pressure gauge i) Open the top cover of the valve and remove the side cover. ii) Remove pressure pickup plug (1) or (2) (10 mm, P = 1.25) and install nipple C3, then connect oil pressure gauge C1 (58.8 MPa {600 kg/cm²} a Use plug (1) to measure the hydraulic pressure in boom, arm, and bucket circuits and use plug (2) to measure the hydraulic pressure in the swing and travel circuits. 2) Measuring unload pressure Measure the hydraulic pressure while the engine is running at full throttle and the control lever is in neutral. 3) Measuring pump relief pressure Measure the hydraulic pressure when each actuator is relieved while the engine is running at full throttle. Measuring hydraulic pressure in swing and blade circuits 1. Measuring pump relief pressure 1) Remove the top cover of the valve. 2) Remove pressure pickup plug (3) (10 mm, P = 1.25) and install nipple C3, then connect oil pressure gauge (58.8 MPa {600 kg/cm²}). a See the photo. 3) Measure the hydraulic pressure when swing or blade lower actuator is relieved while the engine is running at full throttle.
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PC78MR-6
TESTING AND ADJUSTING
TESTING AND ADJUSTING HYDRAULIC PRESSURE IN WORK EQUIPMENT, SWING, AND TRAVEL CIRCUITS
2. Adjusting Adjusting main relief valve for boom, arm, bucket, swing, and travel circuits. • Remove cap (2) of main relief valve (1) and loosen locknut (3), then adjust with adjustment screw (4). a As the adjustment screw is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of adjustment screw: 12.5 MPa {128 kg/cm²} Locknut: 39 – 49 Nm {4 – 5 kgm} Cap: 39 – 49 Nm {4 – 5 kgm}
PC78MR-6
20-119
TESTING AND ADJUSTING
TESTING AND ADJUSTING HYDRAULIC PRESSURE IN WORK EQUIPMENT, SWING, AND TRAVEL CIRCUITS
2. Adjusting Adjusting main relief valve for swing and blade (LOWER) circuits • Remove cap (6) of main relief valve (5) and loosen locknut (7), then adjust with adjustment screw (8). a As the adjustment screw is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of adjustment screw: 12.5 MPa {128 kg/cm²}. Locknut : 39 – 49 Nm {4 – 5 kgm} Cap : 39 – 49 Nm {4 – 5 kgm}
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Adjusting main relief valve for blade (RAISE) circuits • Remove cap (10) of main relief valve (9) and loosen locknut (11), then adjust with adjustment screw (12). a As the adjustment screw is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of adjustment screw: 19.6 MPa {200 kg/cm²}. Locknut : 39 – 49 Nm {4 – 5 kgm} Cap : 39 – 49 Nm {4 – 5 kgm}
PC78MR-6
TESTING AND ADJUSTING
MEASURING LS DIFFERENTIAL PRESSURE AND ADJUSTING LS VALVE
MEASURING LS DIFFERENTIAL PRESSURE AND ADJUSTING LS VALVE 1. Measuring LS differential pressure 1) Measuring with main relief differential pressure gauge i) Remove pump pressure pickup plug (1) (on the high pressure side) and disconnect LS pressure hose (2). Install nipple C3 to the high pressure side and nipple C4 to the LS pressure side. ii) Connect differential pressure gauge C5. a Connect the high pressure side of the differential pressure gauge to the main relief pressure side and connect the low pressure side to the LS pressure side. iii) Measure the LS differential pressure under the condition in Table 1. Table 1 Fuel Control Dial
Operation
Differential Pressure {kg/cm²}
FULL
Set lever in neutral
2.5 – 4.4 {25 – 45}
FULL
Curl bucket (With lever at FULL position)
2.11 – 0.1 {21.5 – 1}
PC78MR-6
2) Measuring with oil pressure gauge a Measure with the same gauge. i) Remove pump pressure pickup plug (1) (on the high pressure side) and disconnect LS pressure hose (2) (on the low pressure side) and install adapter C3. ii) Connect pressure gauge C1 (39.2 MPa {400 kg/cm²}). a Use a pressure gauge having unit divisions of 1.0 MPa {10 kg/cm²}. (If a pressure gauge of 39.2 MPa {400 kg/ cm²} is not available, one of 58.8 MPa {600 kg/cm²} will do.) iii) Measure the pump discharge pressure under the condition in Table 1. Read the pointer correctly, facing the gauge. iv) Measure the LS pressure under the condition in Table 1. a Read the pointer correctly, facing the gauge. a LS differential pressure = (Pump discharge pressure) – (LS pressure)
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TESTING AND ADJUSTING
MEASURING LS DIFFERENTIAL PRESSURE AND ADJUSTING LS VALVE
Adjusting 1. Adjusting LS valve a If the differential pressure is abnormal, adjust the LS valve according to the following procedure. a Before loosening the locknut, be sure to make match marks. 1) Loosen locknut (3) and adjust with adjustment screw (4). a As the adjustment screw is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of adjustment screw: 1.27 MPa {13 kg/cm²}. 2) After adjusting, tighten locknut (3). Locknut: 29.4 – 39.2 Nm {3 – 4 kgm} a After adjusting, measure the LS differential pressure, referring to Measuring described above. a When loosening or tightening the locknut, secure adjustment screw (4) with a spanner so that it will not be dragged.
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PC78MR-6
TESTING AND ADJUSTING
ADJUSTING PC VALVE a When the load is increased, the engine speed may lower or the engine speed may be normal and working speed may be lower. If this trouble occurs and the pump discharge pressure and LS differential pressure are normal, adjust the pump PC valve according to the following procedure. a Before loosening locknut, be sure to make match marks. 1. Loosen locknut (1) and adjust with adjustment screw (2). a Since the PC valve is of eccentric type, in which direction the adjustment screw should be turned to increase the absorption torque is unknown. Accordingly, monitor the engine speed when turning the adjustment screw. 2. After adjusting, tighten locknut (1).
ADJUSTING PC VALVE
TESTING TVC-EPC SOLENOID OUTPUT PRESSURE Measuring a Hydraulic oil temperature for measurement: 45 – 55 °C 1) Remove pump pressure pickup plug (1) (10 mm, P = 1.25) and install nipple C3 of the oil pressure gauge kit and connect oil pressure gauge kit and connect oil pressure gauge C1 (5.9 MPa {60 kg/cm²}).
Locknut: 29.4 – 39.2 Nm {3 – 4 kgm}
2) Start the engine and measure the oil pressure under the following condition. Table 1 Measurement Condition Engine Speed
PC78MR-6
MeasureMeasured Monitor Output ment Pressure MPa Current Condition {kg/cm²}
FULL
Neutral
0.54 – 0.84 {5.5 – 8.5}
410 mA
FULL
Float one side and run idle
0 – 0.2 {0 – 2}
100 mA
SLOW
Neutral
2.74 – 3.53 {28 – 36}
900 mA
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TESTING AND ADJUSTING
MEASURING CONTROL CIRCUIT PRESSURE
MEASURING CONTROL CIRCUIT PRESSURE Measuring a Hydraulic oil temperature for measurement: 45 – 55 °C Lower the work equipment to the ground and stop the engine. Then, loosen the hydraulic oil filler cap slowly to release the internal pressure of the hydraulic tank. Set the safety valve lock lever to the LOCK position. 1) Remove the front cover front guard plate of the valve. 2) Remove pressure pickup plug (1) (10 mm, P = 1.25) from the top of the solenoid valve block.
4) Start and run the engine at full throttle and measure the circuit pressure. Adjusting • If the control circuit pressure is abnormal, adjust the control relief valve according to the following procedure. 1) Loosen locknut (2) of relief valve (1) and adjust with adjustment screw (3). a As the adjustment screw is • rotated to the right, the pressure is heightened, and it is • rotated to the left, the pressure is lowered. a Quantity of adjustment per turn of adjustment screw: 0.32 MPa {3.3 kg/cm²}. Locknut: 20 – 29 Nm {2 – 3 kgm} a After adjusting, check the set pressure according to the procedure in 1.
3) Connect nipple C3 and install oil pressure gauge C1 (5.8 MPa {60 kg/cm²}).
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PC78MR-6
TESTING AND ADJUSTING
MEASURING PPC VALVE OUTPUT PRESSURE
MEASURING PPC VALVE OUTPUT PRESSURE a Hydraulic oil temperature for measurement: 45 – 55 °C 1. Measuring PPC valve output pressure 1) Disconnect hose (1) of the circuit to be measured.
a Measuring points a. Blade RAISE
J. LEFT swing
b. Blade LOWER
k. Boom RAISE
c. RIGHT swing
l.
d. LEFT swing
m. Arm OUT
e. LEFT REVERSE travel
n. Arm IN
f.
o. Bucket DUMP
LEFT FORWARD travel
Boom LOWER
g. RIGHT REVERSE travel
p. Bucket CURL
h. RIGHT FORWARD travel
q. Service
i.
r.
RIGHT swing
Service
2) Install adapter C4 between hose (1) and elbow. 3) Install oil pressure gauge C1 (5.9 MPa {60 kg/cm²}) to adapter C3. 4) Run the engine at full throttle and operate the control lever of the circuit to be measured and measure oil pressure.
a If the output on the control valve side is low, measure the input pressure of the PPC valve. Of the input pressure of the PPC valve is normal, the PPC valve is defective.
PC78MR-6
20-125
TESTING AND ADJUSTING
TESTING SOLENOID VALVE OUTPUT PRESSURE
TESTING SOLENOID VALVE OUTPUT PRESSURE a Hydraulic oil temperature for measurement: 45 – 55 °C 1. Measuring output pressure of boom swing stop EPC solenoid valve 1) Disconnect EPC solenoid valve output hose (1) and install oil pressure gauge C1 (5.9 MPa {60 kg/cm²}), using nipples C3 and C4 in the oil pressure gauge kit. a The EPC solenoid valve is installed in the 6-spool solenoid valve assembly under the floor plate.
Measuring 1. Measuring output pressure of ON-OFF solenoid valve. 1) Disconnect ON-OFF solenoid valve output hose and install oil pressure gauge C1 (5.9 MPa {60 kg/cm²}), using nipple C3 and C4 in the oil pressure gauge kit. 2) Measure the output pressure of the solenoid valve under the condition in Table 2. a The ON-OFF solenoid valve. • Installed in the 6-spool soleoid valve assembly at the front under the floor plate.
2) Measure the output pressure under the condition in Table 1.
Table 1 Oil pressure MPa {kg/cm²}
Remarks
While boom is swinging to right
3.14 ± 0.49 {32 ± 5}
—
Stroke end
1.13 ± 0.29 {11.5 ± 3}
—
While boom is swinging to left
3.14 ± 0.49 {32 ± 5}
—
Stroke end
1.13 ± 0.29 {11.5 ± 3}
—
Solenoid Name
1
2
Measurement Condition
Swing right stop EPC
Boom swing stop EPC
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PC78MR-6
TESTING AND ADJUSTING
TESTING SOLENOID VALVE OUTPUT PRESSURE
Table 2 Solenoid Name
PPC 1 oil pressuressure lock
Swing hold2 ing brake
Travel speed 3 selector
Operation of Oil pressure solenoid MPa {kg/cm²}
Measurement Condition
Operating Condition
Remarks
Set safety lock lever in FREE position.
Oil pressure is applied to PPC valve circuit.
ON
3.14 ± 0.29 {32 ± 3}
—
Set safety lock lever in LOCK position.
Oil pressure is not applied to PPC valve circuit.
OFF
0
—
Operate swing or boom swing or arm-in lever.
Brake is released.
ON
3.14 ± 0.49 {32 ± 5}
—
Set swing or arm-in lever in neutral (5 sec after Brake is applied. setting in neutral)
OFF
0
—
Set travel speed selector Travel speed is switch in Hi. increased.
ON
3.14 ± 0.49 {32 ± 5}
—
Set travel speed selector Travel speed is switch in Lo. decreased.
OFF
0
—
Note: Operation of solenoid valve is as follows; When ON: Power is applied (Hydraulic oil is generated). When OFF: Power is not applied (Hydraulic oil is 0).
PC78MR-6
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TESTING AND ADJUSTING
ADJUSTING WORK EQUIPMENT VALVE AND SWING PPC VALVE
ADJUSTING WORK EQUIPMENT VALVE AND SWING PPC VALVE If the work equipment control lever or swing control lever has excessive play, adjust it according to the following procedure. Lower the work equipment to the ground and stop the engine. Then, loosen the hydraulic oil filler cap slowly to release the internal pressure of the hydraulic tank. Set the safety valve lock lever to the LOCK position. 1. Remove the PPC valve. 2. Remove bolt (1). 3. Loosen locknut (2) and screw in disc (3) until it touches the heads of 4 pistons (4). a At this time, do not move the pistons. 4. Fix disc (3) and tighten locknut (2) to the specified torque. Locknut: 98 – 127 Nm {10 – 13 kgm} 5. Install boot (1). a The clearance between disc (3) and piston (4) is eliminated by the above adjustment.
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PC78MR-6
TESTING AND ADJUSTING
TESTING TRAVEL DEVIATION
TESTING TRAVEL DEVIATION 1. Measuring when traveling 1) Set the machine in the travel posture. a For the travel posture, extend the bucket and arm cylinder rods fully, and hold the boom angle at 45°. 2) Travel for 10 m, then measure deviation a when traveling for the next 20 m. a Measure with the engine at full throttle. a Install a hydraulic pressure gauge and measure the pump discharge pressure a the same time.
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20-129
TESTING AND ADJUSTING
Adjusting a Travel deviation can be corrected by draining a part of the oil discharged from the pump which discharges more oil with the adjustment plugs. If the travel deviation is corrected by this method, however, the travel speed, work equipment speed in the compound operation, and relief pressure lower since the pump discharge is reduced. a The following is the method of correcting deviation applied when the machine deviates to the right (left) in both travel directions. a Travel deviation can be corrected by the following method only when it is 200 mm or less.
TESTING TRAVEL DEVIATION
2. Insert hexagonal wrench (1) (Width across flats: 4 mm) in adjustment plug (1) or (2). a Insert the hexagonal wrench securely. 3. Loosen locknut (3), leaving the hexagonal wrench inserted. a Before adjusting, mark the position of the locknut with paint. a Loosen the locknut, securing the hexagonal wrench. • Loosening angle of locknut: Approx. 90 – 180°
If the adjustment plug is loosened more than the adjustment limit, high pressure oil spurts out. Take care extremely. Lower the work equipment to the ground and stop the engine. Then, loosen the hydraulic oil filler cap slowly to release the internal pressure of the hydraulic tank. 1. Check the position of each adjustment plug of the main pump. • When the machine deviates to the right: Loosen adjustment plug (1). • When the machine deviates to the left: Loosen adjustment plug (2). a Loosen only either plug. Do not loosen both plugs at the same time.
4. Correct the travel deviation by loosening adjustment plug (1) or (2). • Quantity of correction of travel deviation per turn of adjustment plug: 150 mm (For reference) a When the machine is shipped, the adjustment plugs are tightened fully. Adjust the correction angle by the loosening angle of the adjustment plugs. a If the adjustment plug is dragged when the locknut is loosened, tighten it again. a The adjustable range of each adjustment plug is 2 turns / 720 degrees from the tightened position. 5. Tighten locknut (3). Locknut:2.94 – 4.9 Nm {0.3 – 0.5 kgm} 6. Check for travel deviation again. If the machine still deviates, adjust again according to the above procedure. a Do not loosen the adjustment plugs more than the adjustable range (2 turns / 720 degrees).
20-130
PC78MR-6
TESTING AND ADJUSTING
TESTING PARTS WHICH CAN CAUSE HYDRAULIC DRIFT OF WORK EQUIPMENT
TESTING PARTS WHICH CAN CAUSE HYDRAULIC DRIFT OF WORK EQUIPMENT a Hydraulic oil temperature for measurement: 45 – 55 °C 1. Work equipment cylinder a If the hydraulic drift of the work equipment exceeds the standard value, measure the leakage in the cylinder according to the following procedure to see if the cause of the hydraulic drift is on the cylinder side or control valve side. • If the leakage is less than the standard value, the cause is on the control valve side. • If the leakage is above the standard value, the cause is on the cylinder side. 1) Extend the rod of the cylinder to be measured and stop the engine. 2) Disconnect hoses (1) – (4) on the head side and block the pipes on the machine side with plugs. 1. Boom cylinder head hose 2. Arm cylinder head hose 3. Bucket cylinder head hose 4. Swing cylinder head hose
3) Run the engine at full throttle and apply relief pressure to the cylinder bottom.
Take care not to disconnect the bottom hoses.
4) After 30 seconds, measure the oil leakage in 1 minute.
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20-131
TESTING AND ADJUSTING
MEASURING OIL LEAKAGE FROM SWING AND TRAVEL MOTORS
MEASURING OIL LEAKAGE FROM SWING AND TRAVEL MOTORS a Hydraulic oil temperature for measurement: 45 – 55 °C 1. Swing motor 1) Disconnect drain hose (1) of the swing motor (on the hydraulic tank side). a Plug the hydraulic tank. 2) Stick the bucket into the ground to lock the swing mechanism. 3) Run the engine at full throttle and relieve the swing circuit. 4) After 30 seconds, measure the oil leakage in 1 minute. a After measuring 1 time, swing 180 degrees and measure again.
20-132
2. Travel motor 1) Disconnect drain hose (3) of the travel motor and plug the hose. 2) Put a block in the grouser of the track shoe or between the sprocket and the frame to lock the track shoe. 3) Run the engine at full throttle and relieve the travel circuit. Since a wrong operation of a lever can cause an accident, make signs and confirm the operations security. 4) After 30 seconds, measure the oil leakage in 1 minute. a Measure the oil leakage several times, moving the motor little by little (shifting the valve plate and piston from the cylinder).
PC78MR-6
TESTING AND ADJUSTING
RELEASING RESIDUAL PRESSURE FROM HYDRAULIC CIRCUIT
RELEASING RESIDUAL PRESSURE FROM HYDRAULIC CIRCUIT a Since an accumulator is not installed, the residual pressure in the piping between the control valve and each hydraulic cylinder or swing motor cannot be released even if the control levers are operated. Accordingly, when removing the above piping, observe the following points. 1) Run the engine at low speed and lower the work equipment to the ground, taking care not to relieve the cylinder at the stroke end, then stop the engine. a If the hydraulic cylinder is relieved at the stroke end before the engine is stopped, do not perform the following work for 5 ~ 10 minutes. 2) Loosen pressure release plug (4) of the control valve gradually to release the residual pressure from the circuit.
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20-133
TESTING AND ADJUSTING
TESTING CLEARANCE OF SWING CIRCLE BEARING
TESTING CLEARANCE OF SWING CIRCLE BEARING Method of testing clearance of swing circle bearing on machine 1. Fix dial gauge with magnet (1) to the swing circle outer ring (2) (or inner ring) (3) and apply the probe to the end face of the inner ring (or outer ring). Set the dial gauge to the front or rear part.
4. Set the arm at about right angles to the ground and lower the boom until the front part of the undercarriage floats. At this time, the front part of the upper structure rises and the rear part lowers. 5. Read the dial gauge. The indicated value is the clearance of the swing circle bearing. Do not put your hand or foot under the undercarriage during measurement.
2. Extend the work equipment to the maximum reach and set the bucket tip to the height of the underside of the revolving frame. At this time, the front part of the upper structure lowers and the rear part rises. 3. Set the dial gauge to the zero point.
20-134
6. Set the machine in the position explained in 2 above again and check that the dial gauge indicates zero. If the dial gauge does not indicate zero, repeat Steps 2 – 5.
PC78MR-6
TESTING AND ADJUSTING
TESTING AND ADJUSTING TRACK SHOE TENSION
TESTING AND ADJUSTING TRACK SHOE TENSION Testing 1. Run the engine at low idling and move the machine forward by the length of the track on the ground and stop slowly. 2. Place square wood bar (3) over idler (1) and carrier roller (2). 3. Measure the maximum distance between the top of the track and the underside of the wood bar. • If the standard slack a is in the following range, the shoe tension is normal. Specification
Standard Slack a
Road liner, steel shoe
10 – 30 mm
Rubber shoe
1 – 3 mm
Adjusting a If the track shoe tension is abnormal, adjust it according to the following procedure. 1. When tension is too high. 1) Loosen valve (1) to discharge grease. Since the high pressure grease may spurt out, do not loosen the valve more than 1 turn. a If the grease is not discharged sufficiently, move the machine slowly forward and in reverse. 2) To check that the track shoe tension is normal, run the engine at low idling and move the machine forward by the length of track on ground and stop slowly. 3) Test the track shoe tension again. If it is still not normal, adjust it again. 2. When tension is low 1) Supply grease through grease fitting (2). a If the track shoe tension is not tensed well, move the machine slowly forward and in reverse. Grease fitting: Grease (G2-LI) 2) To check that the track shoe tension is normal, run the engine at low idling and move the machine forward by the length of track on ground and stop slowly. 3) Test the track shoe tension again. If it is still not normal, adjust it again.
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20-135
TESTING AND ADJUSTING
BLEEDING AIR FROM HYDRAULIC CIRCUIT
BLEEDING AIR FROM HYDRAULIC CIRCUIT Contents of work and procedures for bleeding air Air bleeding item
Procedure for Bleeding Air 1
—
Bleeding air from pump
Starting engine
Q
Q
Contents of work • Replacing hydraulic oil • Cleaning strainer
Q
Q
3
Bleeding air from cirBleeding cuit between air from LS circuit pump and hydraulic tank
Q
Q
• Replacing return filter element • Replacing or repairing pump • Removing suction pipe
2
Q
4
5
6
7
8
Bleeding air from cylinders
Bleeding air from swing motor
Bleeding air from travel motor
Bleeding air from swing PPC circuit
Starting operation
Q
Q Note)
Q Note)
Q
Q Q
Q
Q Q
• Replacing or repairing control valve
Q
Q
• Replacing cylinder • Removing cylinder piping
Q
Q
• Replacing swing motor • Removing swing motor piping
Q
• Replacing travel motor and swivel • Removing travel motor and swivel
Q
• Replacing or removing swing PPC circuit parts (Swing PPC valve, piping, pressure switch, etc.)
Q
Q Q
Q Q
Q
Q Q
Q Q
Q
Note: Bleed air from the swing motor and travel motor only after the oil in the motor case is drained. 1. Bleeding air from pump a If the pump is operated without filling pump case with hydraulic oil, it is heated abnormally and may be broken soon. Accordingly, bleed all air from the pump before operating the pump. 1) Loosen air bleeder (1) installed to the drain port and check that oil oozes out. 2) After bleeding air, tighten the air bleeder.
2. Bleeding air between pump and hydraulic tanks. a If the pump is operated without bleeding air from the circuit between the pump and hydraulic tank, it is heated abnormally and may be broken soon. Accordingly, bleed all air. 1) Run the engine at medium speed (approx. 1,650 rpm) 2) Operate the work equipment slowly for about 5 minutes to bleed air.
Bleeder: 7.8 – 9.8 Nm {0.8 – 1.0 kgm} 3. Bleeding air from LS circuit a Bleed air only after the hoses of the pump, valve, and LS circuit are replaced. a If air is not bled from the LS circuit, the work equipment may malfunction. 1) Loosen air bleeder (2) installed to the LS port of the pump. 2) Run the engine at low idling for 2 minutes. 3) Operate the bucket (dump and curl bucket to the stroke ends) for about 2 minutes. 4) After bleeding air, tighten air bleeder (2).
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TESTING AND ADJUSTING
BLEEDING AIR FROM HYDRAULIC CIRCUIT
4. Bleeding air from hydraulic cylinder a If the engine speed is heightened or the cylinder is moved to the stroke end at first, the air in the cylinder will damage the piston packing, etc. 1) Run the engine at medium speed (approx. 1,650 rpm) and move each cylinder to about 100 mm before each stroke end 4 – 5 times. a Never relieve the oil. 2) Move each cylinder to each stroke end 3 – 4 times. 3) Move each cylinder to each stroke end 4 – 5 more times to bleed air. 5. Bleeding air from swing motor a Bleed air from the swing motor only after the oil is drained from the swing motor case. a If the swing motor is operated without bleeding air from it, its bearings may be broken. 1) Run the engine at low idling and loosen drain hose (2). If oil oozes out, tighten the drain hose. a Do not swing the machine while bleeding air. 2) Keep the engine speed at low idling and swing evenly at least 2 turns in each direction.
7. Bleeding air from swing PPC circuit 1) Stick the bucket into the ground to lock the swing mechanism. 2) Run the engine at low idling. 3) Loosen air bleeders (4) and (5) of the control valve. 4) Move the swing control lever through the full stroke repeatedly to check that all air is bled through bleeders (4) and (5). 5) Tighten bleeders (4) and (5). Bleeder: 7.8 – 9.8 Nm {0.8 – 1.0 kgm}
6. Bleeding air from travel motor a Bleed air from the travel motor only after the oil is drained from the travel motor case. 1) Run the engine at low idling and loosen drain hose (3). If oil oozes out, tighten the drain hose. 2) Keep the engine speed at low idling and swing 90? and float the track a little with the work equipment, then run idle for 2 minutes. 3) Perform Step 2 above for each side.
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20-137
TESTING AND ADJUSTING
REPLACEMENT PROCEDURE OF POTENTIOMETERS
REPLACEMENT PROCEDURE OF POTENTIOMETERS 1. Remove boom swing potentiometer assemblies (1), from the work equipment . a Do not swing a removed potentiometer assembly around its lever or turn the lever unnecessarily. 2. Install potentiometer assemblies (1). 3. Be sure to reset input and output signals.
20-138
PC78MR-6
TESTING AND ADJUSTING
PROCEDURE FOR TESTING DIODE
PROCEDURE FOR TESTING DIODE •
Inspect a diode or a wiring harness containing a diode according to the following procedure. • Use a digital tester having a diode range. 1. Apply the red (+) test pin to the anode (P) side of the diode, and the black (-) test pin to the cathode (N) side. a The current flow mark is printed on the diode body.
PC78MR-6
2. Set the tester in the diode range, and the voltage of the battery in it is indicated. If this voltage • does not change, the diode doesn't have continuity. • changes, the diode has continuity (normal) (Note). • 0 or near 0, the diode is shorted in it. Note: A normal silicon diode indicates 450 – 600.
20-139
TROUBLESHOOTING Points to remember when troubleshooting.................................................................................................. 20-202 SEQUENCE of events in troubleshooting ................................................................................................... 20-203 Point to remember when carrying out maintenance ................................................................................... 20-204 Checks before troubleshooting ................................................................................................................... 20-212 Type and location of connectors ................................................................................................................. 20-214 Connector arrangement diagram ................................................................................................................ 20-216 Connection table for connector pin numbers .............................................................................................. 20-219 Explanation of functions of electric system control mechanism .................................................................. 20-242 Display and special functions of monitor panel ........................................................................................... 20-243 TVC valve current adjustment table ............................................................................................................ 20-254 Adjusting service meter............................................................................................................................... 20-255 Method of using judgement table ................................................................................................................ 20-256 How to read flow of troubleshooting............................................................................................................ 20-258 Contents and procedure of troubleshooting ................................................................................................ 20-260 Troubleshooting for engine (S mode).......................................................................................................... 20-301 Troubleshooting for communication system (N mode)................................................................................ 20-401 Troubleshooting for controller (governor control system) (E mode)............................................................ 20-501 Troubleshooting for controller (pump control system) (C mode)................................................................. 20-601 Troubleshooting for controller (input signal system) (F mode).................................................................... 20-701 Troubleshooting for hydraulic and mechanical systems (H mode) ............................................................. 20-801 Troubleshooting for machine monitor system (M mode) ............................................................................. 20-901
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TROUBLESHOOTING
POINTS TO REMEMBER WHEN TROUBLESHOOTING
POINTS TO REMEMBER WHEN TROUBLESHOOTING Stop the machine in a level place, and check that the safety pin, blocks, and parking brake are securely fitted. When carrying out the operation with two or more workers, keep strictly to the agreed signals, and do not allow any unauthorized person to come near. If the radiator cap is removed when the engine is hot, hot coolant may spurt out and cause burns, so wait for the engine to cool down before starting troubleshooting. Be extremely careful not to touch any hot parts or to get caught in any rotating parts. When disconnecting wiring, always disconnect the negative (–) terminal of the battery first. When removing the plug or cap from a location which is under pressure from oil, water or air, always release the internal pressure first. When installing measuring equipment, be sure to connect it properly. The aim of troubleshooting is to pinpoint the basic cause of the failure, to carry out repairs swiftly, and to prevent reoccurrence of the failure. When carrying out troubleshooting, an important point is to understand the structure and function of the machine. However, a short cut to effective troubleshooting is to ask the operator various questions to form some idea of possible causes of the failure that would produce the reported symptoms. 1. When carrying out troubleshooting, do not hurry to disassemble the components. If components are disassembled immediately after a failure occurs: • Parts that have no connection with the failure or other unnecessary parts will be disassembled. • It will become impossible to find the cause of the failure. It will also cause a waste of man hours, parts, or oil and grease. At the same time, it will also lose the confidence of the user or operator. For this reason, when carrying out troubleshooting, it is necessary to carry out thorough prior investigation and to carry out troubleshooting in accordance with the fixed procedure. 2. Points to ask the user or operator. 1) Have any other problems occurred apart from the problem that has been reported? 2) Was there anything strange about the machine before the failure occurred? 3) Did the failure occur suddenly, or were there problems with the machine condition before this? 4) Under what conditions did the failure occur? 5) Had any repairs been carried out before the failure? When were these repairs carried out? 6) Has the same kind of failure occurred before?
4) Check the stroke of the control valve spool. 5) Other maintenance items can be checked externally, so check any item that is considered to be necessary. 4. Confirming the failure. Confirm the extent of the failure yourself, and judge whether to handle it as a real failure or as a problem with the method of operation, etc. a When operating the machine to re-enact the troubleshooting symptoms, do not carry out any investigation or measurement that may make the problem worse. 5. Troubleshooting Use the results of the investigation and inspection in Steps 2 – 4 to narrow down the causes of the failure, then use the troubleshooting flowchart to locate the position of the failure exactly. a The basic procedure for troubleshooting is as follows. 1) Start from the simple points. 2) Start from the most likely points. 3) Investigate other related parts or information. 6. Measures to remove root cause of failure. Even if the failure is repaired, if the root cause of the failure is not repaired, the same failure will occur again. To prevent this, always investigate why the problem occurred. Then, remove the root cause.
3. Check before troubleshooting. 1) Check the oil level. 2) Check for any external leakage of oil from the piping or hydraulic equipment. 3) Check the travel of the control levers.
20-202
PC78MR-6
TROUBLESHOOTING
SEQUENCE OF EVENTS IN TROUBLESHOOTING
SEQUENCE OF EVENTS IN TROUBLESHOOTING
TEW00180
TEW00181
Step 1 Examination, confirmation of symptoms 1) When a request for repairs is received, first ask the following points. • Name of customer • Type, serial number of machine • Details of jobsite, etc. 2) Ask questions to gain an outline of the problem. • Condition of failure • Work being carried out at the time of the failure • Operating environment • Past history, details of maintenance, etc.
Step 2 Determining probable location of cause 1) Look at the troubleshooting section of the shop manual to find locations of possible causes.
Step 3 Preparation of troubleshooting
tools
1) Look at the table of troubleshooting tools in the shop manual and prepare the necessary tools. • T-adapter • Hydraulic pressure gauge kit, etc. 2) Look in the parts book and prepare the necessary replacement parts.
Step 7 • Pinpoint locations of failure (carry out troubleshooting) • Decide action to take
TEW00186
1) Before starting troubleshooting, locate and repair simple failures. • Check before starting items • Other check items 2) See the Troubleshooting Section of the shop manual, select a troubleshooting flowchart that matches the symptoms, and carry out troubleshooting.
TEW00187
Step 6 Re-enacting failure •
Step 4 Go to jobsite
Step 5 Ask operator questions to confirm details of failure. • • • TEW00189
PC78MR-6
Drive and operate the machine to confirm the condition and judge if there is really a failure.
Was there anything strange about the machine before the failure occurred? Did the failure occur suddenly? Had any repairs been carried out before the failure?
20-203
TROUBLESHOOTING
POINT TO REMEMBER WHEN CARRYING OUT MAINTENANCE
POINTS TO REMEMBER WHEN CARRYING OUT MAINTENANCE To maintain the performance of the machine over a long period, and to prevent failures or other troubles before they occur, correct operation, maintenance and inspection, troubleshooting, and repairs must be carried out. This section deals particularly with correct repair procedures for mechatronics and is aimed at improving the quality of repairs. For this purpose, it gives sections on "Handling electric equipment" and "Handling hydraulic equipment" (particularly gear oil and hydraulic oil). 1. Points to remember when handling electric equipment 1) Handling wiring harnesses and connectors Wiring harnesses consist of wiring connecting one component to another component, connectors used for connecting and disconnecting one wire from another wire, and protectors or tubes used for protecting the wiring. Compared with other electrical components fitted in boxes or cases, wiring harnesses are more likely to be affected by the direct effects of rain, water, heat, or vibration. Furthermore, during inspection and repair operations, they are frequently removed and installed again, so they are likely to suffer deformation or damage. For this reason, it is necessary to be extremely careful when handling wiring harnesses.
Main failures occurring in wiring harness 1) Defective contact of connectors (defective contact between male and female) Problems with defective contact are likely to occur because the male connector is not properly inserted into the female connector, or because one or both of the connectors is deformed or the position is not correctly aligned, or because there is corrosion or oxidization of the contact surfaces.
2) Defective crimping or soldering of connectors The pins of the male and female connectors are in contact at the crimped terminal or soldered portion, but if there is excessive force brought to bear on the wiring, the plating at the joint will peel and cause improper connection or breakage.
20-204
PC78MR-6
TROUBLESHOOTING
POINT TO REMEMBER WHEN CARRYING OUT MAINTENANCE
3) Disconnections in wiring If the wiring is held and the connectors are pulled apart, or components are lifted with a crane with the wiring still connected, or a heavy object hits the wiring, the crimping of the connector may separate, or the soldering may be damaged, or the wiring may be broken.
4) High-pressure water entering connector The connector is designed to make it difficult for water to enter (drip-proof structure), but if high-pressure water is sprayed directly on the connector, water may enter the connector, depending on the direction of the water jet. As already said, the connector is designed to prevent water from entering, but at the same time, if water does enter, it is difficult for it to be drained. Therefore, if water should get into the connector, the pins will be short-circuited by the water, so if any water gets in, immediately dry the connector or take other appropriate action before passing electricity through it. 5) Oil or dirt stuck to connector If oil or grease are stuck to the connector and an oil film is formed on the mating surface between the male and female pins, the oil will not let the electricity pass, so there will be defective contact. If there is oil or grease stuck to the connector, wipe it off with a dry cloth or blow it dry with compressed air and spray it with a contact restorer. a When wiping the mating portion of the connector, be careful not to use excessive force or deform the pins. a If there is oil or water in the compressed air, the contacts will become even dirtier, so remove the oil and water from the compressed air completely before cleaning with compressed air.
PC78MR-6
20-205
TROUBLESHOOTING
POINT TO REMEMBER WHEN CARRYING OUT MAINTENANCE
2) Removing, installing, and drying connectors and wiring harnesses •
Disconnecting connectors 1) Hold the connectors when disconnecting. When disconnecting the connectors, hold the connectors and not the wires. For connectors held by a screw, loosen the screw fully, then hold the male and female connectors in each hand and pull apart. For connectors which have a lock stopper, press down the stopper with your thumb and pull the connectors apart. a Never pull with one hand. 2) When removing from clips When removing a connector from a clip, pull the connector in a parallel direction to the clip. a If the connector is twisted up and down or to the left or right, the housing may break.
3) Action to take after removing connectors After removing any connector, cover it with a vinyl bag to prevent any dust, dirt, oil, or water from getting in the connector portion. a If the machine is left disassembled for a long time, it is particularly easy for improper contact to occur, so always cover the connector.
20-206
PC78MR-6
TROUBLESHOOTING
•
POINT TO REMEMBER WHEN CARRYING OUT MAINTENANCE
Connecting connectors Check the connector visually. 1) Check that there is no oil, dirt, or water stuck to the connector pins (mating portion). 2) Check that there is no deformation, defective contact, corrosion, or damage to the connector pins. 3) Check that there is no damage or breakage to the outside of the connector. a If there is any oil, water, or dirt stuck to the connector, wipe it off with a dry cloth. If any water has got inside the connector, warm the inside of the wiring with a dryer, but be careful not to make it too hot as this will cause short circuits. a If there is any damage or breakage, replace the connector. Fix the connector securely. Align the position of the connector correctly, then insert it securely. For connectors with lock stopper, push in the connector until the stopper clicks into position. Correct any protrusion of the boot and any misalignment of the wiring harness For connectors fitted with boots, correct any protrusion of the boot. In addition, if the wiring harness is misaligned, or the clamp is out of position, adjust it to its correct position. a If the connector cannot be corrected easily, remove the clamp and adjust the position. If the connector clamp has been removed, be sure to return it to its original position. Check also that there are no loose clamps.
•
Since the DT 8-pole and 12-pole heavy duty wire connectors have 2 latches respectively, push them in until they click 2 times. 1. Male connector, 2. Female conector • Normal locking state (Horizontal): a, b, d • Incomplete locking state (Diagonal): c
PC78MR-6
20-207
TROUBLESHOOTING
•
POINT TO REMEMBER WHEN CARRYING OUT MAINTENANCE
Drying wiring harness If there is any oil or dirt on the wiring harness, wipe it off with a dry cloth. Avoid washing it in water or using steam. If the connector must be washed in water, do not use high-pressure water or steam directly on the wiring harness. If water gets directly on the connector, do as follows. Disconnect the connector and wipe off the water with a dry cloth. a If the connector is blown dry with compressed air, there is the risk that oil in the air may cause defective contact, so remove all oil and water from the compressed air before blowing with air.
Dry the inside of the connector with a dryer. If water gets inside the connector, use a dryer to dry the connector. a Hot air from the dryer can be used, but regulate the time that the hot air is used in order not to make the connector or related parts too hot, as this will cause deformation or damage to the connector.
Carry out a continuity test on the connector. After drying, leave the wiring harness disconnected and carry out a continuity test to check for any short circuits between pins caused by water. a After completely drying the connector, blow it with contact restorer and reassemble.
20-208
PC78MR-6
TROUBLESHOOTING
POINT TO REMEMBER WHEN CARRYING OUT MAINTENANCE
3) Handling control box 1) The control box contains a microcomputer and electronic control circuits. These control all of the electronic circuits on the machine, so be extremely careful when handling the control box. 2) Do not open the cover of the control box unless necessary.
3) Do not place objects on top of the control box. 4) Cover the control connectors with tape or a vinyl bag. Never touch the connector contacts with your hand. 5) During rainy weather, do not leave the control box in a place where it is exposed to rain.
6) Do not place the control box on oil, water, or soil, or in any hot place, even for a short time. (Place it on a suitable dry stand).. 7) Precautions when carrying out arc welding When carrying out arc welding on the body, disconnect all wiring harness connectors connected to the control box. Fit an arc welding ground close to the welding point.
2. Points to remember when troubleshooting electric circuits 1) Always turn the power OFF before disconnecting or connect connectors. 2) Before carrying out troubleshooting, check that all the related connectors are properly inserted. a Disconnect and connect the related connectors several times to check. 3) Always connect any disconnected connectors before going on to the next step.. a If the power is turned ON with the connectors still disconnected, unnecessary abnormality displays will be generated. 4) When carrying out troubleshooting of circuits (measuring the voltage, resistance, continuity, or current), move the related wiring and connectors several times and check that there is no change in the reading of the tester. a If there is any change, there is probably defective contact in that circuit.
PC78MR-6
20-209
TROUBLESHOOTING
POINT TO REMEMBER WHEN CARRYING OUT MAINTENANCE
3. POINTS TO REMEMBER WHEN HANDLING HYDRAULIC EQUIPMENT With the increase in pressure and precision of hydraulic equipment, the most common cause of failure is dirt (foreign material) in the hydraulic circuit. When adding hydraulic oil, or when disassembling or assembling hydraulic equipment, it is necessary to be particularly careful. 1) Be careful of the operating environment. Avoid adding hydraulic oil, replacing filters, or repairing the machine in rain or high winds, or places where there is a lot of dust. 2) Disassembly and maintenance work in the field If disassembly or maintenance work is carried out on hydraulic equipment in the field, there is danger of dust entering the equipment. It is also difficult to confirm the performance after repairs, so it is desirable to use unit exchange. Disassembly and main-tenance of hydraulic equipment should be carried out in a specially prepared dustproof workshop, and the performance should be confirmed with special test equipment.
3) Sealing openings After any piping or equipment is removed, the openings should be sealed with caps, tapes, or vinyl bags to prevent any dirt or dust from entering. If the opening is left open or is blocked with a rag, there is danger of dirt entering or of the surrounding area being made dirty by leaking oil so never do this. Do not simply drain oil out on to the ground, collect it and ask the customer to dispose of it, or take it back with you for disposal.
4) Do not let any dirt or dust get in during refilling operations. Be careful not to let any dirt or dust get in when refilling with hydraulic oil. Always keep the oil filler and the area around it clean, and also use clean pumps and oil containers. If an oil cleaning device is used, it is possible to filter out the dirt that has collected during storage, so this is an even more effective method.
20-210
PC78MR-6
TROUBLESHOOTING
POINT TO REMEMBER WHEN CARRYING OUT MAINTENANCE
5) Change hydraulic oil when the temperature is high. When hydraulic oil or other oil is warm, it flows easily. In addition, the sludge can also be drained out easily from the circuit together with the oil, so it is best to change the oil when it is still warm. When changing the oil, as much as possible of the old hydraulic oil must be drained out. (Drain the oil from the hydraulic tank; also drain the oil from the filter and from the drain plug in the circuit.) If any old oil is left, the contaminants and sludge in it will mix with the new oil and will shorten the life of the hydraulic oil.
6) Flushing operations After disassembling and assembling the equipment, or changing the oil, use flushing oil to remove the contaminants, sludge, and old oil from the hydraulic circuit. Normally, flushing is carried out twice: primary flushing is carried out with flushing oil, and secondary flushing is carried out with the specified hydraulic oil.
7) Cleaning operations After repairing the hydraulic equipment (pump, control valve, etc.) or when running the machine, carry out oil cleaning to remove the sludge or contaminants in the hydraulic oil circuit. The oil cleaning equipment is used to remove the ultrafine (about 3µ) particles that the filter built into the hydraulic equipment cannot remove, so it is an extremely effective device.
PC78MR-6
20-211
TROUBLESHOOTING
CHECKS BEFORE TROUBLESHOOTING
CHECKS BEFORE TROUBLESHOOTING Judgement Value
Action
1. Check fuel level, type of fuel
—
Add fuel
2. Check for impurities in fuel
—
Clean, drain
3. Check hydraulic oil level
—
Add oil
4. Check hydraulic oil strainer
—
Clean, drain
5. Check swing machinery oil level
—
Add oil
6. Check engine oil level, type of engine oil
—
Add oil
7. Check coolant level
—
Add coolant
8. Check dust indicator for clogging
—
Clean or replace
9. Check hydraulic oil filter
—
Replace
1. Check for looseness, corrosion of battery terminal, wiring
—
Tighten or replace
2. Check for looseness, corrosion of alternator terminal, wiring
—
Tighten or replace
3. Check for looseness, corrosion of starting motor terminal, wiring
—
Tighten or replace
1. Check for abnormal noise, smell
—
Repair
2. Check for oil leakage
—
Repair
3. Carry out air bleeding
—
Bleed air
20 - 30 V
Replace
2. Check battery electrolyte level
—
Add or replace
3. Check for discolored, burnt, exposed wiring
—
Replace
4. Check for missing wiring clamps, hanging wire
—
Repair
5. Check for water leaking on wiring (Pay particular attention to water leaking on connectors or terminals)
—
Disconnect connector and dry
6. Check for blown, corroded fuses
—
Replace
After running for several minutes: 27.5 ~ 29.5 V
Replace
—
—
Hydraulic, mechanical equipment
Electrical equipment
Lubricating oil, coolant
Item
Electrical equipment
1. Check battery voltage (Engine stopped)
7. Check alternator voltage (Engine running at 1/2 throttle or above) 8. Sound of actuation of battery relay (When starting switch is turned ON, OFF)
20-212
PC78MR-6
TROUBLESHOOTING
TYPE AND LOCATION OF CONNECTORS
TYPE AND LOCATION OF CONNECTORS a The addresses in the follwing table are the addresses used in the connector arrangement drawing (3-dimensional drawing). Connector No.
Type
No. of Pins
Address
Connector No.
Type
No. of Pins
A/C
X
1
Air conditioner compressor
L7
K20
M
8
Cab inlet
R6
D4
SWP
2
Diode (Engine stop solenoid)
H1
K21
S
8
Cab inlet
R6
D5
SWP
2
Diode (Battery relay BR)
G1
K23
5
Starting motor cut-out relay
R8
D6
SWP
2
Diode (Battery relay BR)
G1
K26
090
2
Horn switch
M7
D11
SWP
2
Diode (TVC solenoid)
R7
K27
SWP
6
Fuel governor control motor
N7
D12
SWP
2
Diode (TVC solenoid)
R8
K28
M
3
PPC hydraulic lock switch
P2
D13
SWP
2
Diode (PPC basic pressure lock solenoid)
Q8
K32
5
Accelerator relay
O8
D22
SWP
2
Diode (Air conditioner compressor)
H1
K33
5
Decelerator relay
N8
D25
SWP
2
Diode (Engine stop solenoid relay)
G1
K42
SUMITOMO
16
Intermediate connector (Reset switch)
P8
D26
SWP
2
Diode (Engine stop solenoid relay)
H9
K45
M
1
Ground (Radio)
Q3
D30
SWP
2
Diode (PPC basic pressure lock solenoid)
R7
K51
090
20
Intermediate connector (Starting, light switch)
M7
D31
SWP
2
Diode (Swing RIGHT stop circuit)
R7
K52
M
3
Light switch
N8
D32
SWP
2
Diode (Swing RIGHT stop circuit)
R6
K53
M
2
Buzzer cancel switch
O8
D33
SWP
2
Diode (Swing LEFT stop circuit)
Q8
K54
M
3
Revolving warning lamp (Optional)
P8
D34
SWP
2
Diode (Swing LEFT stop circuit)
P8
M1
L
2
Intermediate connector (Power supply, ground)
M4
EU1
M
2
Overload warning cancel switch (*1)
R5
M2
X
2
Intermediate connector (Power supply)
M4
Fuse box
R3
M3
DT (Gr)
8
Intermediate connector (Rotation sensor, etc.)
M4
FB1
Location
Address
Location
GND Terminal
1
Key stop solenoid
L2
M4
DT (G)
8
Intermediate connector (Swing angle sensor, etc.)
M4
HOLD Terminal
1
Key stop solenoid
L2
M5
DT (Gr)
8
Intermediate connector (TVC solenoid)
M3
K1
S
12
Intermediate connector (Monitor panel)
M7
M6
DT (B)
8
Intermediate connector (Related to pressure switch)
M3
K2
S
16
Intermediate connector (Monitor panel)
N7
M7
DT (G)
8
For connection of boom pressure sensor (*1)
M3
K3
DT
2
2nd travel speed selection solenoid valve
O2
M9
DT
2
Fuel sensor
I2
K11
SWP
12
Auto A/C unit
O2
M11
DT
2
Boom swing LEFT stop solenoid
N2
K12
M
2
Resister
P8
M12
DT
2
Boom swing RIGHT stop solenoid
N2
K17
X
2
Optional power supply unit
P2
M13
DT
2
PPC hydraulic lock solenoid
M2
K18
090
2
Decelerator switch
Q2
M13
M
2
Speaker (Right)
I9
K19
PA
9
Radio
R3
M14
DT
2
Parking brake solenoid
N2
*1. For EU spec. machine only.
20-214 (1)
PC78MR-6
TROUBLESHOOTING
Connector No.
Type
No. of Pins
M15
DT
2
M16
DT
M17
TYPE AND LOCATION OF CONNECTORS
Address
Connector No.
Type
No. of Pins
Travel speed shifting solenoid
M2
P15
040
2
Sunlight sensor (Optional)
M6
2
Engine speed sensor
J3
1
Key stop solenoid
L3
X
1
Glow plug
K8
T1
Terminal
1
Revolving frame ground (Controller system)
I2
M18
DT
2
Engine water temperature sensor
L8
T2
Terminal
1
Revolving frame ground
H2
M20
DT
2
TVC/EPC solenoid
K8
T3
Terminal
1
Revolving frame ground (Controller SIG system)
H1
M21
X
2
Pressure switch (Boom RAISE)
G9
T4
Terminal
1
Alternator (Terminal R)
L6
M22
X
2
Pressure switch (Swing)
I9
T5
Terminal
1
Alternator (Terminal B)
L6
M23
X
2
Pressure switch (Swing)
G9
T6
Terminal
1
Engine oil pressure switch
L5
M24
X
2
Pressure switch (Arm IN)
H9
T9
Terminal
1
Battery relay (Terminal E)
A4
M25
X
2
Pressure switch (Travel)
I9
T10
Terminal
1
Battery relay (Terminal BR)
A3
M26
L
2
Fusible link
C8
T11
Terminal
1
Battery relay (Terminal M)
A6
M27
L
2
Fusible link
B8
T12
Terminal
1
Battery relay (Terminal B)
A5
M28
DT
2
Intermediate connector (Working lamp)
J9
T16
Terminal
1
Engine stop solenoid relay
K3
M30
X
2
Safety relay (S, R)
J3
T17
Terminal
1
Engine stop solenoid relay
K3
M31
KES
2
Windshield washer
C8
T31
Terminal
1
Safety relay (Terminal B)
K3
M32
DT
2
Travel/Swing alarm
J2
T32
Terminal
1
Safety relay (Terminal C)
L5
M35
L
2
Junction wiring harness
K1
T33
Terminal
1
Starting motor (Terminal B)
L7
M36
DT
2
Engine stop solenoid
J2
T34
Terminal
1
Starting motor (Terminal C)
L6
M71
M
2
Room light
J9
W04
M
6
Wiper motor
M5
M73
M
2
Speaker (Left)
J9
W19
2
Cigarette lighter
M5
M75
DT
2
Working lamp
D9
B
Terminal
1
Starting switch (Terminal B)
M9
M80
040
2
Horn
M2
BR
Terminal
1
Starting switch (Terminal BR)
M8
M92
DT
3
Boom bottom pressure sensor (*1)
D2
ACC
Terminal
1
Starting switch (Terminal ACC)
M8
M95
DRC23
24
Controller
R8
C
Terminal
1
Starting switch (Terminal C)
M9
M96
DRC23
40
Controller
Q8
R1
Terminal
1
Starting switch (Terminal R1)
N8
M97
DRC23
40
Controller
Q8
R2
Terminal
1
Starting switch (Terminal R2)
N8
M101
DT
3
Boom swing angle potentiometer
F1
P01
040
12
Monitor panel
M6
P02
P040
20
Monitor panel
M6
Location
PULL Terminal
Address
Location
*1. For EU spec. machine only.
PC78MR-6
20-215 (1)
TROUBLESHOOTING
CONNECTOR ARRANGEMENT DIAGRAM
CONNECTOR ARRANGEMENT DIAGRAM *1. For EU spec. machine only.
20-216 (1)
PC78MR-6
TROUBLESHOOTING
PC78MR-6
CONNECTOR ARRANGEMENT DIAGRAM
20-217 (1)
TROUBLESHOOTING
CONNECTOR ARRANGEMENT DIAGRAM
*1. For EU spec. machine only.
20-218 (1)
PC78MR-6
TROUBLESHOOTING
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS a The terms male and female refer to the pins while the terms male housing and female housing refer to the mating portion of the housing. X-Type Connector
Number of Pins
Male (Female Housing)
Female (Male Housing)
T-adapter Part Number
1
Part Number: 08055-00181
Part Number: 08055-00191
799-601-7010
BWP04702 2
799-601-7020
Part Number: 08055-00282
Part Number: 08055-00292
BWP04703 3
BWP04704
Part Number: 08055-00381
BWP04705
4
Part Number: 08055-00481
799-601-7030
Part Number: 08055-00391
BWP04706
799-601-7040
Part Number: 08055-00491
—
Terminal part number: 79A-222-3370 • Wire size: 0.85 • Grommet: black • Quantity: 20 pieces
Terminal part number: 79A-222-3390 • Wire size: 0.85 • Grommet: black • Quantity: 20 pieces
—
—
Terminal part number: 79A-222-3380 • Wire size: 2.0 • Grommet: red • Quantity: 20 pieces
Terminal part number: 79A-222-3410 • Wire size: 2.0 • Grommet: red • Quantity: 20 pieces
—
PC78MR-6
20-219
TROUBLESHOOTING
Number of Pins
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
SWP-Type Connector Male (Female Housing)
Female (Male Housing)
T-adapter Part Number
BWP04707 6
799-601-7050
Part Number: 08055-10681
8
BWP04709
Part Number: 08055-10881
BWP04711 12
Part Number: 08055-11281
BWP04713
Part Number: 08055-10691
BWP04710 799-601-7060
Part Number: 08055-10891
BWP04712
Part Number: 08055-11291
BWP04714
14
799-601-7070
Part Number: 08055-11481
20-220
799-601-7310
Part Number: 08055-11491
PC78MR-6
TROUBLESHOOTING
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
SWP-Type Connector
Number of Pins
Male (Female Housing)
BWP04715
16
Part Number: 08055-11681
Female (Male Housing)
BWP04716
T-adapter Part Number
799-601-7320
Part Number: 08055-11691
—
Terminal part number: • Wire size: 0.85 • Grommet: black • Quantity: 20 pieces
Terminal part number: • Wire size: 0.85 • Grommet: black • Quantity: 20 pieces
—
—
Terminal part number: • Wire size: 1.25 • Grommet: red • Quantity: 20 pieces
Terminal part number: • Wire size: 1.25 • Grommet: red • Quantity: 20 pieces
—
PC78MR-6
20-221
TROUBLESHOOTING
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
M-Type Connector
Number of Pins
Male (Female Housing)
Female (Male Housing)
T-adapter Part Number
1
Part Number: 08056-00171
Part Number: 08056-00181
799-601-7080
2
BWP04717
Part Number: 08056-00271
3
BWP04719
Part Number: 08056-00371
4
BWP04721
Part Number: 08056-00471
6
BWP04723
Part Number: 08056-00671
8
BWP04725
Part Number: 08056-00871
20-222
BWP04718 799-601-7090
Part Number: 08056-00281
BWP04720
799-601-7110
Part Number: 08056-00381
BWP04722
799-601-7120
Part Number: 08056-00481
BWP04724
799-601-7130
Part Number: 08056-00681
BWP04726
799-601-7340
Part Number: 08056-00881
PC78MR-6
TROUBLESHOOTING
Number of Pins
8
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
S-Type Connector Male (Female Housing)
BWP04727
Part Number: 08056-10871
10 (White)
BWP04729
Part Number: 08056-11071
12 (White)
BWP04731
Part Number: 08056-11271
16 (White)
BWP04733
Part Number: 08056-11671
PC78MR-6
Female (Male Housing)
T-adapter Part Number
BWP04728 799-601-7140
Part Number: 08056-10881
BWP04730
799-601-7150
Part Number: 08056-11081
BWP04732
799-601-7350
Part Number: 08056-11281
BWP04734
799-601-7330
Part Number: 08056-11681
20-223
TROUBLESHOOTING
Number of Pins
10 (Blue)
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
S-Type Connector Male (Female Housing)
BWP04735
—
12 (Blue)
BWP04737
Part Number: 08056-11272
16 (Blue)
BWP04739
Part Number: 08056-11672
20-224
Female (Male Housing)
T-adapter Part Number
BWP04736 —
—
BWP04738
799-601-7160
Part Number: 08056-11282
BWP04740
799-601-7170
Part Number: 08056-11682
PC78MR-6
TROUBLESHOOTING
Number of Pins
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
MIC-Type Connector Male (Female Housing)
Female (Male Housing)
T-adapter Part Number
7
Body Part Number: 79A-222-2640 (Quantity: 5 pieces)
Body Part Number: 79A-222-2630 (Quantity: 5 pieces)
—
11
Body Part Number: 79A-222-2680 (Quantity: 5 pieces)
Body Part Number: 79A-222-2670 (Quantity: 5 pieces)
—
5
BWP04741
Body Part Number: 79A-222-2620 (Quantity: 5 pieces)
9
BWP04743
Body Part Number: 79A-222-2660 (Quantity: 5 pieces)
13
BWP04745
Body Part Number: 79A-222-2710 (Quantity: 5 pieces)
PC78MR-6
BWP04742 799-601-2710
Body Part Number: 79A-222-2610 (Quantity: 5 pieces)
BWP04744
799-601-2950
Body Part Number: 79A-222-2650 (Quantity: 5 pieces)
BWP04746
799-601-2720
Body Part Number: 79A-222-2690 (Quantity: 5 pieces)
20-225
TROUBLESHOOTING
Number of Pins
17
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
MIC-Type Connector Male (Female Housing)
BWP04747
Body Part Number: 79A-222-2730 (Quantity: 2 pieces)
21
20-226
BWP04749
Female (Male Housing)
T-adapter Part Number
BWP04748 799-601-2730
Body Part Number: 79A-222-2720 (Quantity: 2 pieces)
BWP04750
Body Part Number: 79A-222-2750 (Quantity: 2 pieces)
Body Part Number: 79A-222-2740 (Quantity: 2 pieces)
Body Part Number: 79A-222-2770 (Quantity: 50 pieces)
Body Part Number: 79A-222-2760 (Quantity: 50 pieces)
799-601-2740
—
PC78MR-6
TROUBLESHOOTING
Number of Pins
8
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
AMP040-Type Connector Male (Female Housing)
BWP04751
—
12
BWP04753
—
16
BWP04755
—
20
BWP04757
—
PC78MR-6
Female (Male Housing)
T-adapter Part Number
BWP04752 799-601-7180
Housing Part Number: 79A-222-3430
BWP047544
799-601-7190
Housing Part Number: 79A-222-3440
BWP04756
799-601-7210
Housing Part Number: 79A-222-3450
BWP04758
799-601-7220
Housing Part Number: 79A-222-3460
20-227
TROUBLESHOOTING
Number of Pins
10
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
AMP070-Type Connector Male (Female Housing)
BWP04759
—
12
BWP04761
—
14
BWP04763
—
18
BWP04765
—
20
BWP04767
—
20-228
Female (Male Housing)
T-adapter Part Number
BWP04760 799-601-7510
Part Number: 08195-10210
BWP04762
799-601-7520
Part Number: 08195-12210
BWP04764
799-601-7530
Part Number: 08195-14210
BWP04766
799-601-7540
Part Number: 08195-18210
BWP04768
799-601-7550
Part Number: 08195-20210
PC78MR-6
TROUBLESHOOTING
Number of Pins
2
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
L-Type Connector Male (Female Housing)
BWP04769
Female (Male Housing)
BWP04770
—
Number of Pins
9
—
—
Female (Male Housing)
T-adapter Part Number
PA-Type Connector Male (Female Housing)
BWP04771
BWP04772
—
Number of Pins
10
— BENDIX MS-Type Connector
Male (Female Housing)
BWP04773
—
PC78MR-6
T-adapter Part Number
Female (Male Housing)
T-adapter Part Number
BWP04774 799-601-3460
—
20-229
TROUBLESHOOTING
Number of Pins
2
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
KES1 Automobile-Type Connector Male (Female Housing)
BWP04775
Part Number: 08027-10210 (Natural color) 08027-10220 (Black)
3
BWP04777
Part Number: 08027-10310
4
BWP04779
Part Number: 08027-10410 (Natural color) 08027-10420 (Black)
6
BWP04781
Part Number: 08027-10610 (Natural color) 08027-10620 (Black)
20-230
Female (Male Housing)
T-adapter Part Number
BWP04776 —
Part Number: 08027-10260 (Natural color) 08027-10270 (Black)
BWP04778
—
Part Number: 08027-10360
BWP04780
—
Part Number: 08027-10460 (Natural color) 08027-10470 (Black)
BWP04782
—
Part Number: 08027-10660 (Natural color) 08027-10670 (Black)
PC78MR-6
TROUBLESHOOTING
Number of Pins
8
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
KES1 Automobile-Type Connector Male (Female Housing)
BWP04783
Part Number: 08027-10810 (Natural color) 08027-10820 (Black)
PC78MR-6
Female (Male Housing)
T-adapter Part Number
BWP04784 —
Part Number: 08027-10860 (Natural color) 08027-10870 (Black)
20-231
TROUBLESHOOTING
Number of Pins
5
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
Socket-Type Connector for Relay Male (Female Housing)
BWP04785
—
6
BWP04787
—
20-232
Female (Male Housing)
T-adapter Part Number
BWP04786 799-601-7360
—
BWP04788 799-601-7370
—
PC78MR-6
TROUBLESHOOTING
Number of Pins
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
F-Type Connector Male (Female Housing)
BWP04785
Female (Male Housing)
BWP04786
4
—
—
PC78MR-6
T-adapter Part Number
—
20-233
TROUBLESHOOTING
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
The pin number is also marked on the connector (Electric wire insertion end). Type (Shell Size Code)
18-8 (1)
18-14 (2)
20-234
HD30 Series Connector Body (Plug)
Body (Receptacle)
Pin (Male Terminal)
Pin (Female Terminal)
Part Number: 08191-11201, 08191-11202, 08191-11205, 08191-11206
Part Number: 08191-14101, 08191-14102, 08191-14105, 08191-14106
Pin (Female Terminal)
Pin (Male Terminal)
Part Number: 08191-12201, 08191-12202, 08191-12205, 08191-12206
Part Number: 08191-13101, 08191-13102, 08191-13105, 08191-13106
Pin (Male Terminal)
Pin (Female Terminal)
Part Number: 08191-21201, 08191-12202, 08191-21205, 08191-12206
Part Number: 08191-24101, 08191-24102, 08191-24105, 08191-24106
Pin (Female Terminal)
Pin (Male Terminal)
Part Number: 08191-22201, 08191-22202 08191-22205, 08191-22206
Part Number: 08191-23101, 08191-23102, 08191-23105, 08191-23106
T-adapter Part Number
799-601-9210
799-601-9220
PC78MR-6
TROUBLESHOOTING
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
The pin number is also marked on the connector (Electric wire insertion end). Type (Shell Size Code)
18-20 (3)
18-21 (4)
PC78MR-6
HD30 Series Connector Body (Plug)
Body (Receptacle)
Pin (Male Terminal)
Pin (Female Terminal)
Part Number: 08191-31201, 08191-31202
Part Number: 08191-34101, 08191-34102
Pin (Female Terminal)
Pin (Male Terminal)
Part Number: 08191-32201, 08191-32202
Part Number: 08191-33101, 08191-33102
Pin (Male Terminal)
Pin (Female Terminal)
Part Number: 08191-41201, 08191-42202
Part Number: 08191-44101, 08191-44102
Pin (Female Terminal)
Pin (Male Terminal)
Part Number: 08191-42201, 08191-42202
Part Number: 08191-43101, 08191-43102
T-adapter Part Number
799-601-9230
799-601-9240
20-235
TROUBLESHOOTING
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
The pin number is also marked on the connector (Electric wire insertion end). Type (Shell Size Code)
24-9 (5)
24-16 (6)
20-236
HD30 Series Connector Body (Plug)
Body (Receptacle)
Pin (Male Terminal)
Pin (Female Terminal)
Part Number: 08191-51201, 08191-51202
Part Number: 08191-54101, 08191-54102
Pin (Female Terminal)
Pin (Male Terminal)
Part Number: 08191-52201, 08191-52202
Part Number: 08191-53101, 08191-53102
Pin (Male Terminal)
Pin (Female Terminal)
Part Number: 08191-61201, 08191-62202, 08191-61205, 08191-62206
Part Number: 08191-64101, 08191-64102, 08191-64105, 08191-64106
Pin (Female Terminal)
Pin (Male Terminal)
Part Number: 08191-62201, 08191-62202, 08191-62205, 08191-62206
Part Number: 08191-63101, 08191-63102, 08191-63105, 08191-63106
T-adapter Part Number
799-601-9250
799-601-9260
PC78MR-6
TROUBLESHOOTING
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
The pin number is also marked on the connector (Electric wire insertion end). Type (Shell Size Code)
HD30 Series Connector Body (Plug)
Body (Receptacle)
Pin (Male Terminal)
Pin (Female Terminal)
Part Number: 08191-71201, 08191-71202, 08191-71205, 08191-71206
Part Number: 08191-74101, 08191-74102, 0819174105, 08191-74106
Pin (Female Terminal)
Pin (Male Terminal)
Part Number: 08191-72201, 08191-72202, 08191-72205, 08191-72206
Part Number: 08191-73101, 08191-73102, 08191-73105, 08191-73106
Pin (Male Terminal)
Pin (Female Terminal)
Part Number: 08191-81201, 08191-81202, 0819181203, 08191-81204, 08191-81205, 08191-81206
Part Number: 08191-84101, 08191-84102, 0819184103, 08191-84104, 08191-84105, 08191-84106
Pin (Female Terminal)
Pin (Male Terminal)
Part Number: 08191-82201, 08191-82202, 0819182203, 08191-82204, 08191-82205, 08191-82206
Part Number: 08191-83101, 08191-83102, 0819183103, 08191-83104, 08191-83105, 08191-83106
24-21 (7)
24-22 (8)
PC78MR-6
T-adapter Part Number
799-601-9270
799-601-9280
20-237
TROUBLESHOOTING
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
The pin number is also marked on the connector (Electric wire insertion end). Type (Shell Size Code)
24-31 (9)
20-238
HD30 Series Connector Body (Plug)
Body (Receptacle)
Pin (Male Terminal)
Pin (Female Terminal)
Part Number: 08191-91203, 08191-91204, 08191-91205, 08191-91206
Part Number: 08191-94103, 08191-94104, 08191-94105,08191-94106
Pin (Female Terminal)
Pin (Male Terminal)
Part Number: 08191-92203, 08191-92204, 08191-92205, 08191-92206
Part Number: 08191-93103, 08191-93104, 08191-93105, 08191-93106
T-adapter Part Number
799-601-9290
PC78MR-6
TROUBLESHOOTING
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
The pin number is also marked on the connector (Electric wire insertion end). No. of Pins
DT Series Connector Body (Plug)
Body (Receptacle)
2
799-601-9020
Part Number: 08192-12200 (Normal type) 08192-22200 (Fine wire type)
Part Number: 08192-12100 (Normal type) 08192-22100 (Fine wire type)
3
799-601-9030
Part Number: 08192-13200 (Normal type) 08192-23200 (Fine wire type)
Part Number: 08192-13100 (Normal type) 08192-23100 (Fine wire type)
4
799-601-9040
Part Number: 08192-14200 (Normal type) 08192-24200 (Fine wire type)
Part Number: 08192-14100 (Normal type) 08192-24100 (Fine wire type)
6
799-601-9050
Part Number: 08192-16200 (Normal type) 08192-26200 (Fine wire type)
PC78MR-6
T-adapter Part Number
Part Number: 08192-16100 (Normal type) 08192-26100 (Fine wire type)
20-239
TROUBLESHOOTING
No. of Pins
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
DT Series Connector Body (Plug)
Body (Receptacle)
8GR:799-601-9060 8B:799-601-9070 8G:799-601-9080 8BR:799-601-9080
8
Part Number: 08192-1820T (Normal type) 08192-2820T (Fine wire type)
Part Number: 08192-1810T (Normal type) 08192-2810T (Fine wire type)
12GR:799-601-9110 12B:799-601-9120 12G:799-601-9130 12BR:799-601-9140
12
Part Number: 08192-1920T (Normal type) 08192-2920T (Fine wire type)
20-240
T-adapter Part Number
Part Number: 08192-1910T (Normal type) 08192-2910T (Fine wire type)
PC78MR-6
TROUBLESHOOTING
CONNECTION TABLE FOR CONNECTOR PIN NUMBERS
The pin number is also marked on the connector (Electric wire insertion end). No. of Pins
DTM Series Connector Body (Plug)
Body (Receptacle)
2
T-adapter Part Number
799-601-9000
Part Number: 08192-02200
Part Number: 08192-02100
The pin number is also marked on the connector (Electric wire insertion end). No. of Pins
DTHD Series Connector Body (Plug)
Body (Receptacle)
Part Number: 08192-31200 (Contact size #12) 08192-41200 (Contact size #8) 08192-51200 (Contact size #4)
Part Number: 08192-31100 (Contact size #12) 08192-41100 (Contact size #8) 08192-51100 (Contact size #4)
T-adapter Part Number
1
PC78MR-6
20-241 (1)
TROUBLESHOOTING
EXPLANATION OF FUNCTIONS OF ELECTRIC SYSTEM CONTROL MECHANISM
EXPLANATION OF FUNCTIONS OF ELECTRIC SYSTEM CONTROL MECHANISM Machine model: PC78MR-6 The control mechanism of the electric system consists of the monitor panel, governor, and pump controller. Those components receive signals necessary to them. The governor and pump controller output or input the necessary signal according to the signals selected by the monitor panel to control the absorption torque, engine output, etc.
Network information 1) Working mode (Standard, E) information 2) One-touch slow-down (ON/OFF) signal 3) Travel Hi/Lo signal 4) Coolant temperature (Water temperature) information
(Monitor panel o Controller) (Monitor panel i Controller) (Monitor panel i Controller) (Monitor panel o Controller)
*1. For EU spec. machine only.
20-242 (1)
PC78MR-6
TROUBLESHOOTING
DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL
DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL 1. Diagnostic function of lamps, gauges, and buzzer If the starting switch is turned ON, all the lamps and gauges light up for about 3 seconds and the buzzer sounds for about 1 second to check the monitor panel, then the monitor panel displays normally (A lamp which does not light up at this time is broken). 2. Function of displaying "user code" All trouble information items of the controller are sent to the monitor panel. An emergent information item among them is displayed as a "user code" automatically on the display (1) of the monitor panel to urge the operator to take proper actions. a The lamps other than display (1), service meter unit (2), and lighting parts (solid parts in the following illustration) are turned OFF.
1) Display of User Code (1) Display (2) Service meter unit (3) Mode selector switch (UP) (4) Mode selector switch (DOWN) (5) Set switch (6) Travel speed selector switch (7) Working mode selector switch (8) Buzzer cancel switch Note) Although switches are not indicated on 3, 4, and 5 of the panel, the functions are installed to the parts at the tips of the arrows. Example) User code "E02" is displayed.
2) User Codes List User Code
Abnormal system
E02
TVC-EPC system
E03
Swing holding brake system
E05
Governor control system
E40
Angle sensor input system
E41
EPC solenoid output system
PC78MR-6
20-243
TROUBLESHOOTING
DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL
3. Function of displaying "service code" All trouble information items of the controller are sent to the monitor panel. All of the information items which must display "user codes" and those which do not need display "user codes" are saved as "service codes" in the monitor panel. If the following operation is executed, the service code is displayed on the display of the monitor panel and the letter "E" to indicate that the trouble is happening currently and the lapse time (service meter reading) are displayed on the service meter unit. 1) Method of displaying and deleting service code i) The service code is displayed by the following procedure: (1) Push and hold the "Buzzer cancel switch (8)" and "Working mode selector switch (7)" for 2.5 seconds. (2) Push the "Buzzer cancel switch (8)" and "Mode selector switch (UP) (3)" [or Mode selector switch (DOWN) (4)] and set "01" tothe 2nd and 3rd columns from the left on service meter unit (2).
(1) Display (2) Service meter unit (3) Mode selector switch (UP) (4) Mode selector switch (DOWN)
(5) Set switch (6) Travel speed switch (7) Working mode selector switch (8) Buzzer cancel switch
(3) Push the "Set switch (5)". Note) Although switches are not indicated on 3, 4, and 5 of the panel, the functions are installed to the parts at the tips of the arrows. Example 1) "01" is displayed on service meter unit (2).
Example 2) "E213" happened 6 hours ago. a If "E213" is still happening, the letter "E" is displayed in the 2nd column of service meter unit (2). If "E213" has been repaired, "E" is not displayed. a The lapse time is displayed in the 3 columns from the right of service meter unit (2).
20-244
PC78MR-6
TROUBLESHOOTING
DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL
Example 3) If any service code is not saved, "-" is displayed in every column of display (1) and service meter unit (2). ii) To see the next displayed service code, push the "Buzzer cancel switch (8)" and "Mode selector switch (UP)" (3). iii) To see the previous displayed service code, push the "Buzzer cancel switch (8)" and "Mode selector switch (DOWN) (4)".
iv) To stop display of the service code, push the "Buzzer c ancel switch (8)" and "Working mode selector switch (7)". v) To delete the saved service codes, press the "Buzzer cancel switch (8)" and turn OFF the "starting switch" simultaneously, then turn ON the "starting switch" again and push and hold the "Buzzer cancel switch (8)" for 5 seconds. a If the number of service codes exceeds 20, they are deleted one by one from the oldest one.
2) Service codes list Error Code
Abnormal System
User Code
E101
Error history data are abnormal
—
E108
Engine coolant temperature is 105°C
—
E112
Short circuit in forward system of wiper motor drive
—
E113
Short circuit in reverse system of wiper motor drive
—
E114
Short circuit in windshield washer drive system
—
E115
Wiper does not start wiping in 10 seconds
—
E116
Wiper is not retracted in 10 seconds
—
E203
Short circuit or grounding fault in swing holding brake solenoid system
E03
E206
Short circuit or grounding fault in 2nd travel speed selection solenoid system
E03
E213
Disconnection in swing holding brake solenoid system
—
E216
Disconnection in 2nd travel speed selection solenoid system
—
E218
Abnormality in communication between monitor panel and controller
—
E227
Short circuit or grounding fault in engine speed sensor system
—
E232
Short circuit or grounding fault in TVC-EPC Solenoid system
E02
E233
Disconnection in TVC-EPC Solenoid system
E02
(*1) E251
Short circuit with chassis ground or disconnection on boom bottom pressure sensor (overload sensor) signal side or (+) side or disconnection on (-) side.
—
E258
Grounding fault on power source side of angle sensors
E304
Short circuit or grounding fault in engine stop solenoid relay system
—
E314
Disconnection in engine stop solenoid relay system
—
E323
Grounding fault in governor control accelerator relays system
E05
E325
Grounding fault in governor control decelerator relays system
E05
E328
Abnormality in governor control motor stal
E05
E412
Abnormality in boom swing angle sensor (Short circuit in power supply)
E40
E413
Abnormality in boom swing angle sensor (Disconnection)
E40
E414
Defective correction of boom swing angle sensor
E451
Short circuit in boom swing LEFT stop EPC system
E41
E452
Disconnection in boom swing LEFT stop EPC system
E41
—
E453
Short circuit in boom swing RIGHT stop EPC system
E41
E454
Disconnection in boom swing RIGHT stop EPC system
E41
E501
Machine model not set
—
E502
Defective machine model selection signal
—
*1. For EU spec. machine only.
PC78MR-6
20-245 (1)
TROUBLESHOOTING
DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL
4. Function of displaying "monitoring code" The input signals from the sensors to each component and the output signals to drive the solenoids can be checked in real time with the monitoring codes. If the following operation is executed, the monitoring code No. is displayed in the 3rd column through the 5th column from the left on service meter unit (2) of the monitor panel and the monitoring information is displayed on display (1).
1) Method of displaying monitoring code i) The monitoring code is displayed by the following procedure: (1) Push and hold the "Buzzer cancel switch (8)" and "Working switch (7)" for 2.5 seconds. (2) Push the "Buzzer cancel switch (8)" and "Mode selector switch (UP) (3)" [or Mode selector switch (DOWN) (4)] and set "02" to the 2nd and 3rd columns from the left on display (2). (3) Push the "Set switch (5)". Note) Although switches are not indicated on 3, 4, and 5 of the panel, the functions are installed to the parts at the tips of the arrows.
(1) Display (2) Service meter unit (3) Mode selector switch (UP) (4) Mode selector switch (DOWN)
(5) Set switch (6) Travel speed switch (7) Working mode selector switch (8) Buzzer cancel switch
Example 1) A numerical monitoring code (Engine speed: 2,050 rpm) is displayed.
Example 2) A bit pattern monitoring code 1020 (ON/OFF input state (1)) is displayed.
20-246
PC78MR-6
TROUBLESHOOTING
DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL
ii) To see the next displayed monitoring code, push the "Buzzer cancel switch (8)" and "Mode selector switch (UP) (3)". iii) To see the previous displayed monitoring code, push the "Buzzer cancel switch (8)" and "Mode selector switch (DOWN) (4)". iv) To stop display of the monitoring code, push and hold the "Buzzer cancel switch (8)" and "Working mode selector switch (5)" for 2.5 seconds. 2) Monitoring codes list a For details of a code marked with "(6 bit)" in the Unit column, see the bit patterns table. Code No.
Item
Unit
Component Name
-
Controller
(6bit)
Controller
0001
Monitor model code
0008
S-NET connection state
0041
Water temperature sensor voltage
10 mA
Controller
0042
Fuel level sensor voltage
10 mA
Controller
0043
Charge voltage
100 mA
Controller
0045
Sensor input 1
(6bit)
Controller
0046
Sensor input 2
(6bit)
Controller
0047
Output state
(6bit)
Controller
0048
Wiper state
(6bit)
Controller
0049
Spare
Controller
0200
Software version No. (Monitor)
Controller
1000
Software version No. (Controller)
If 1.0 is displayed, version No. of controller is 1.0.
Controller
1001
Attachment selection
00: Standard arm
Controller
1010
Engine speed
1020
10 rpm
Controller
ON/OFF input 1
(6bit)
Controller
1021
ON/OFF input 2
(6bit)
Controller
1022
ON/OFF input 3
(6bit)
Controller
1023
ON/OFF input 4
(6bit)
Controller
1024
ON/OFF input/output
(6bit)
Controller
1025
ON/OFF input/output
(6bit)
Controller
1026
ON/OFF input/output
(6bit)
Controller
1033
Boom swing angle sensor voltage
V
Controller
1050
EPC output current (TVC)
10 mA
Controller
1052
EPC output current (Boom swing LEFT stop)
Controller
1053
EPC output current (Boom swing RIGHT stop)
If 55 is displayed, current is 55 mA. If cur- 10 mA rent is 1 A, however, FF is displayed. 10 mA
Controller
1060
ON/OFF output
(6bit)
Controller
PC78MR-6
20-247
TROUBLESHOOTING
DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL
3) Bit patterns list (Bits of corresponding Nos. light up) a [1] - [6] on digital display unit (1) are bit Nos. a The monitoring code No. (4 digits) is displayed in the 2nd column through 5th column from the left on service meter display unit (2).
Code No.
0008
0045
0046 0047
0048
0049
1020
1021
20-248
Item
S-NET connection state
Sensor input 1
Sensor input 2 State of output
State of wiper
Spare
ON/OFF input 1 For detail of model selection, see Table 1. For detail of ATT selection, see Table 2.
ON/OFF input 2
Bit
Details (State When Bit Lights Up)
(1)
ID2 is connected.
(2)
ID3 is connected.
(3)
ID4 is connected.
(4)
ID5 is connected.
(5)
ID6 is connected.
(6)
ID7 is connected.
(1)
Starting switch is at "ON"
(2)
Starting switch is at "START"
(3)
Starting switch is at "PREHEAT"
(4)
Light switch is at "ON"
(2)
Constant bit
(3)
Engine oil pressure (When low)
(6)
Charge level is low (Engine is stopped)
(1)
Buzzer output
(2)
Washer output (Washer switch is turned ON)
(3)
Wiper output 1
(4)
Wiper output 2
(5)
Wiper output 3
(6)
Wiper output 4
(2)
Buzzer cancel switch
(3)
Window limit switch (ON)
(4)
W contact (Wiper is operated)
(5)
P contact (Wiper is operated)
(1)
ATT selection 2 (GND is connected)
(2)
ATT selection 1 (GND is connected)
(3)
Model selection 1 (GND is connected)
(4)
ATT selection 3 (GND is connected)
(5)
UU/US selection (GND is connected)
(6)
Model selection 2 (GND is connected)
(1)
MR selection (GND in connected)
(3)
Compressor signal
(4)
—
(5)
(a) Tier 2 selection signal (When power source is connected)
PC78MR-6
TROUBLESHOOTING
Code No.
1022
Item
ON/OFF input 3
1023
1024
1025
1026
1060
PC78MR-6
ON/OFF input 4
ON/OFF input/output
ON/OFF input/output
ON/OFF input/output
ON/OFF input/output
DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL
Bit
Details (State When Bit Lights Up)
(1)
2nd travel speed selection switch (Panel)
(2)
Working mode selector switch
(3)
Backup light
(4)
SET/CLEAR switch
(5)
Mode selector (E) switch
(6)
Mode selector (R) switch
(3)
Travel pressure switch
(4)
Swing pressure switch
(5)
Arm IN pressure switch
(6)
Boom RAISE pressure switch
(1)
Deceleration signal
(2)
Acceleration signal
(3)
Motor drive power supply
(4)
Auto deceleration signal
(5)
Motor relay (-)
(6)
Motor relay (+)
(1)
—
(2)
Display selector switch (Monitor)
(3)
Arm ground angle alarm cancel switch
(6)
Bucket dump prohibition solenoid + Rotary lamp
(1)
Deceleration switch
(2)
Alarm cancel
(3)
Emergency work equipment operation switch
(4)
2nd travel speed selection switch (Pedal)
(5)
Slide arm limit switch
(1)
Swing holding brake switch (Brake is released)
(2)
PPC main pressure lock (Main pressure lock is reset)
(4)
2nd travel speed is selected (Machine travels at 2nd gear speed)
(5)
Travel/Swing alarm (Alarm is output)
20-249
TROUBLESHOOTING
DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL
Table 1 Model selection table
PC78MR-6
Model Selection 1
Model Selection 2
GND
OPEN
Table 2 1:Connection of the attachment selection wires is shown. (The bits of GND are displayed during normal operation.) Connection table of attachment selection wires Attachment
Attachment Selection (1)
Attachment Selection (2)
Attachment Selection (3)
GND
OPEN
OPEN
Standard specification Standard arm
20-250
PC78MR-6
TROUBLESHOOTING
DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL
Procedure for correcting angle sensor Back mode (When SP monitor is used)
Table 2 Method of selecting back mode and ordinary display Back Mode Mode Code (Note 3)
PC78MR-6 B Buzzer cancel a
Working mode selection
b
Travel
c
SET/CLEAR
d
Model selection (E)
e
Model selection (R)
01 Emergency Trouble (Note 4)
02
06
These modes are set to 2 levels (Note 8) Error Memory Display
Correction Next Item Monitoring of potenti(Note 6) ometer
Previous Item (Note 6)
Error Memory Deletion
Q
Q
—
—
—
Q
Q
Q
Q
Q
Q
Q
Q
Q
Q Q Q
Wiper selection Washer Continuous operation time (SEC) Note 1) Note 3) Note 4) Note 6) Note 8)
2.5
5 (Note 1)
Limited to 5 seconds after the power is turned ON. Displayed on the service meter unit. A flag from the controller is a trigger. Used to save monitoring error. Select with Buzzer cancel + Working mode selection. Select next or previous items with Buzzer cancel + E/R. Enter each mode with the SET/CLEAR switch. Since the suitches "c, d and e" are not indicated on the panel of model MR, operate the same parts as the panel of model MR.
PC78MR-6
20-251
TROUBLESHOOTING
DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL
"06" Correction of boom swing angle sensor The stroke end is saved for initial setting of each cylinder (portion where the angle sensor is installed). No.
Operation
Display "S-1" is displayed on the display section.
1
(1) Set the starting switch to the ON position or run the engine, and then hold warning buzzer cancel switch (B) and working mode selector switch (a) for 2.5 seconds or longer. (2) Set the code of the service meter section to "06". (B) + (d): Increase code. (B) + (e): Decrease code. (3) Press switch (c). Set the machine in "position 1" and press switch (c). (Position 1) • Boom swing RIGHT end
After switch (c) is pressed, "ooo" is displayed, and then "S-2" is displayed on the display section.
If the system is not reset normally, "– – –" flashes.
When abnormal
Set the machine in "position 2" and press switch (c). (Position 2) • Boom swing LEFT end
After switch (c) is pressed, "ooo" is displayed, and then "– – –" is displayed on the display section.
When normal
2
When normal
(Completion of setting) 3
If the system is not reset normally, "– – –" flashes.
4
When abnormal (Flashing)
To finish monitoring, perform the operation of 1-(1), and the monitor panel returns to the ordinary display state.
a If the system is not reset normally, the data before writing are deleted and the initial data are applied. Accordingly, be sure to reset again. * Although switches are not indicated on 3, 4, and 5 of the panel, the functions are installed to the parts at the tips of the arrows.
UU monitor panel
B: The buzzer cancel switch is installed to the right console.
20-252
PC78MR-6
TROUBLESHOOTING
DISPLAY AND SPECIAL FUNCTIONS OF MONITOR PANEL
"20" How to improve exhaust gas color at high altitude • Adjust the TVC current in this mode to reduce the pump absorption torque and improve the exhaust gas color at high altitude. a The work equipment speed, travel speed, and swing speed are lowered by the following operation. a The following operation is not necessary for the normal work. No.
Operation
1
1) Turn the starting switch ON or run the engine and hold buzzer cancel switch (B), travel speed shifting switch (b), and switch (c) for 2.5 seconds. 2) Adjustment code (3) is displayed (flashed) at the left 2 positions and set value (4) is displayed (lighted) at the right 1 position on display unit (1). "5-5E7" (S-SET) is displayed on service meter unit (2). Although switches are not indicated on b, c, and d of the panel, the functions are installed to the parts at the tips of the arrows.
2
Adjustment code "20" flashes. Set the adjustment code with switch (c). • The flashing adjustment code lights up. • The lighting set value flashes.
3
Increase or decrease the set value with switches (d) or (e) and set it with switch (c). • (d): Code is increased. • (e): Code is decreased. • The lighting adjustment code flashes again. • The flashing set value lights up again. For details of the adjustment code and set value, see the TVC valve current adjustment table.
4
To finish adjustment of the TVC valve current, perform Step 1-1), and the monitor panel returns to the normal display state. The set value is saved when the monitor panel returns to the normal display state. Caution: If the mode is reset forcibly by turning the starting switch OFF, the set value is not changed.
5
Display
Change of setting is completed.
[ 1] Flashing: Code/Set value can be changed. [ 2] Lighting: Code is selected/set.
To initialize the set value of the TVC valve current adjustment mode, set the adjustment code and the set value to "40" and "1" respectively with switches (d) and (e), and then finish the adjustment mode.
Note) If switch (d) or (e) is pressed at Step 2, the adjustment code changes. Accordingly, do not press those switches.
UU monitor panel
B: The buzzer cancel switch is installed to the right console.
PC78MR-6
20-253
TROUBLESHOOTING
TVC VALVE CURRENT ADJUSTMENT TABLE
TVC VALVE CURRENT ADJUSTMENT TABLE Adjustment code Set value Initial (Left 2 positions of (Right 1 position of value display unit) display unit)
20
20-254
Contents
0
Increase pump absorption torque by +2.0 kgm (-100 mA).
1
Increase pump absorption torque by +1.5 kgm (-75 mA).
2
Increase pump absorption torque by +1.0 kgm (-50 mA).
3
Increase pump absorption torque by +0.5 kgm (-25 mA).
4
Q
Exhaust gas color
Bad
Initial value
5
Decrease pump absorption torque by -0.5 kgm (+25 mA)
6
Decrease pump absorption torque by -1.0 kgm (+50 mA)
7
Decrease pump absorption torque by -1.5 kgm (+75 mA)
8
Decrease pump absorption torque by -2.0 kgm (+100 mA)
Good
PC78MR-6
TROUBLESHOOTING
ADJUSTING SERVICE METER
ADJUSTING SERVICE METER •
Adjust the service meter when the monitor panel is replaced.
1. Turn the starting switch ON. 2. To set the monitor panel in the service meter adjustment mode, hold buzzer cancel switch (8) and press the following switches on the monitor panel in the order of 1) - 4). 1) Travel speed switch (6) 2) Set switch (5) 3) Working mode selector switch (7) 4) Mode selector (UP) switch (3) a If the monitor panel is set in the adjustment mode, both ends of service meter (2) flash alternately. 3. To select a digit to be corrected, press the buzzer cancel switch (8), working mode selector switch (7), and set switch (5) simultaneously. Each time those switches are pressed, the selected position moves to the left. (The selected position moves to the left only. After it reaches to the left end, it returns to the right end again.)
The monitor panel of the MR specification also has switches (3) – (5).
4. To set or change the figure, press the buzzer cancel switch (8), working mode selector switch (7), and mode selector (UP) switch (3) simultaneously. 5. To finish the service meter adjustment mode, repeat Step 2. a The currently saved service meter value cannot be reduced (returned to a smaller value). When the service meter adjustment is finished after the service meter is set to a large value, that value cannot be reduced either. Take care.
PC78MR-6
20-255
TROUBLESHOOTING
METHOD OF USING JUDGEMENT TABLE
METHOD OF USING JUDGEMENT TABLE This decision list is a tool (decision table) for selecting whether a nature of trouble of a chassis is caused by an electrical system failure or a hydraulic or mechanical failure and advancing to troubleshooting codes (N-OO, EOO, S-OO , C-OO, F-OO, H-OO, M-OO) that match each event. The decision table identifies that processing should advance to which troubleshooting codes according to the presence of the display of user and service codes. a The abnormality display (warning) using the monitor panel directly advances to machine monitor troubleshooting code (M-OO). (Refer to the machine monitor system troubleshooting.) 1. Controller (Governor Control System) or Engine Related Decision List • When a service code is displayed on the monitor panel, advance to troubleshooting code (E-OO) of the lowermost step of the decision table. (A q is marked to the point where a failure mode and a service code match.) • If a service code is not displayed and a nature of trouble appears in the monitor panel, advance to diagnostic code (E-OO or S-OO) at the right end which matches the failure mode of the decision list. Failure mode "Engine does not start" [Procedure] Test that a service code is displayed on the monitor panel.
[Decision] 1) When a service code is displayed on the monitor panel: ....... Run a diagnostic check using the controller (decelerator control) system "E3:OO". 2) When a service code is not displayed on the monitor panel and "Engine does not start": When the starting motor rotates: .... Advance to mechanical system troubleshooting "S-2". • Check the rotation When the starting motor does not rotate: of a starting motor. .... Advance to electrical system troubleshooting "E-8".
20-256
PC78MR-6
TROUBLESHOOTING
METHOD OF USING JUDGEMENT TABLE
2. Controller (Pump Control System) or Oil Pressure Related Decision Table • When a service code is displayed on the monitor panel, advance to the troubleshooting code (C-OO) of the lowermost step of the decision table. (A q is marked to the point where a failure mode and a service code match.) • If a service code is not displayed and a nature of trouble appears in the monitor panel, check the display of an input signal that matches the failure mode of the decision table (display the location marked with a circle (O)) and • When an input signal is displayed normally, advance to the diagnostic code (H-OO) at the right of the decision list. • When an input signal is not displayed, advance to the diagnostic code (F-OO) at the lowermost step of the decision list. Failure mode "Swing is not performed" [Procedure] Test that a service code is displayed on the monitor panel.
[Decision] 1) When a service code is displayed on the monitor panel: ....... Run a diagnostic check using the controller (pump control) system "C:OO". 2) When a service code is not displayed on the monitor panel and "Swing is not performed": • Check controller input When the signal is provided: signal. .... Advance to mechanical system troubleshooting "H-34" and "C-38". (Check it in the monitorWhen the signal is not provided: ing mode.) .... Advance to the CR700 controller input signal system troubleshooting "F-OO". (See section F mode)
PC78MR-6
20-257 (1)
TROUBLESHOOTING
HOW TO READ FLOW OF TROUBLESHOOTING
HOW TO READ FLOW OF TROUBLESHOOTING 1. Classification of diagnosis code Nos. Diagnosis Code No.
Objective System of Diagnosis
Service code
S-QQ
Engine body
N-QQ
Communication system
E-QQ
Electric system of controller (Governor control system)
E323, E325, E328
C-QQ
Electric system of controller (Pump control system)
E232, E233
F-QQ
Controller (Input signal system)
H-QQ
Hydraulic and mechanical systems
M-QQ
Monitor panel
—
— E1-QQ
2. How to read troubleshooting (method) for each failure mode 1) Title column In the title column of the troubleshooting, the troubleshooting code, service code, and failure mode (trouble) are entered. 2) Classification of cases If the troubleshooting method for a failure mode (a trouble) varies with the machine model, component, phenomenon, the failure mode (the trouble) is classified further (This work is called classification of cases), execute an applicable one. (See (2) in the example.) If the cases are not classified, start troubleshooting from the first of the failure mode. 3) How to carry out troubleshooting • Perform checking or measurement in the first step . Then, select either branch of YES and NO and go to the next step . (Note: The "No." at the right shoulder of each is the reference No. It is not the No. of the step.) • If the branch of YES or NO is connected directly to the Cause column, take the remedy shown in the Remedy column. (See (3) in the example.) • Under the , the method of inspection, measurement, judgment, etc. are shown. If the result is matched to the criterion, question, etc., take the branch of YES. If not, take the branch of NO. • Under the , preparation work for inspection and measurement and criterion are also shown. If your neglect the preparation work or take a wrong method of operation or handling, you may have a wrong judgment or may damage the devices. Accordingly, read well before starting inspection and measurement, then carry out the work in the correct order. 4) General precautions The general precautions for troubleshooting of each failure mode (trouble) are marked with a under the title (See (4) in the example). The precautions marked with a are not shown in the . Be sure to take them when performing the inspections in the . 5) Diagnostic tools For the diagnostic tools necessary for troubleshooting, see TESTING AND ADJUSTING, Diagnostic tools list. Prepare them before starting the work.
20-258
PC78MR-6
TROUBLESHOOTING
HOW TO READ FLOW OF TROUBLESHOOTING
6) Locations and connector pin Nos. Before starting the work, check the Nos., inspection points, types, and locations of the wiring connectors which appear in the flow of the troubleshooting for each failure mode (trouble) with the table of locations and Nos. of connector pins. (1) M-1[E101](Error history data are abnormal) is displayed (2) a This error is displayed when the connector P01, connector K1, fuse 18, connector M6, connector M2, battery relay terminal B, or battery terminal in the monitor panel power supply system is disconnected or connected for troubleshooting. This phenomenon does not indicate an error. (When the power supply circuit of the monitor panel is cut out while the starting switch is at the OFF position.) a If the service code is displayed again after the resetting operation is performed, carry out the troubleshooting according to the following procedure.
Cause • After resetting operation, operate machine normally and observe its condition for a while. (See Note 1.)
Remedy
1 NO
After "resetting operation", is service code displayed again?
Normal
—
Disconnection, defective contact, or short circuit with chassis ground in wiring harness between battery – battery relay B – M27 (1), (2) – P01 (Female) (8)
Repair or replace
Defective monitor panel
Replace
YES
2 • Turn starting switch OFF • 20 – 30 V
Is voltage between P01 (8) – chassis ground normal?
YES
PC78MR-6
NO
20-259
TROUBLESHOOTING
CONTENTS AND PROCEDURE OF TROUBLESHOOTING
CONTENTS AND PROCEDURE OF TROUBLESHOOTING If a trouble occurs, carry out troubleshooting according to the judgment table, controller (governor control system), and controller (pump control system). For the detailed contents and procedure of the troubleshooting, however, see the following flow. Before starting the troubleshooting, ask the operator about the trouble as long as possible and check the following items in advance. (1) Connecting condition of the controller (Check with monitoring code 0001), (2) Breakage of the fuses, (3) Battery voltage, (4) Generating (charge input) voltage (Monitoring code 0043 "H-34").
YES
1 Is user code displayed on monitor panel?
E02
(PC-EPC system)
E03
(Swing holding brake and 2nd travel speed selection solenoid systems)
E05
(Governor motor system)
o Go to No. 2
E200 group: Troubleshooting for pump controller (Pump control system) (C-mode)
Carry out troubleshooting in corresponding mode.
YES E300 group: Troubleshooting for pump controller (Governor control system) (E-mode) 2 NO
Is service code displayed on monitor panel? • Operate and check service code.
YES
Carry out troubleshooting by engine (in S-mode).
5 Engine system 4 YES 3 NO
Is input/output signal of controller normal? • Check by monitoring code.
Is trouble in engine system or hydraulic (Mechanical) system? • Adjust hydraulic pressure, then judge by engine speed. • Is work equipment always heavy and does engine speed lower under heavy load?
Is electric system of engine with no failure code normal? • Flow of part of judgment table where no troubles are indicated. NO
Hydraulic Mechanical System NO
Carry out troubleshooting by electric system of engine (in E-mode). (Flow of part where there is no indication) (E-6 – E8)
(Carry out troubleshooting in Hmode).
Troubleshoot by input signal system (F-mode).
a Judge the details by judgment table for controllers (governor control system) (pump control system). For the No. and contents of monitoring, see the monitoring codes table.
20-260
PC78MR-6
TROUBLESHOOTING OF ENGINE (S MODE) Method of using troubleshooting chart........................................................................................................ 20-302 S- 1 Starting performance is poor (Starting always takes time) ............................................................... 20-306 S- 2 Engine does not start ....................................................................................................................... 20-308 (1) Engine does not turn.................................................................................................................. 20-308 (2) Engine turns no but exhaust smoke comes out (Fuel is not being injected) .............................. 20-309 (3) Exhaust smoke comes out but engine does not start (Fuel is being injected) ........................... 20-310 S- 3 Engine does not pick up smoothly (Follow-up is poor) ......................................................................20-311 S- 4 Engine stops during operations ........................................................................................................ 20-312 S- 5 Engine does not rotate smoothly (Hunting) ...................................................................................... 20-313 S- 6 Engine lacks output (or lacks power) ............................................................................................... 20-314 S- 7 Exhaust smoke is black (Incomplete combustion) ........................................................................... 20-315 S- 8 Oil consumption is excessive (or exhaust smoke is blue) ................................................................ 20-316 S- 9 Oil becomes contaminated quickly ................................................................................................... 20-317 S-10 Fuel consumption is excessive......................................................................................................... 20-318 S-11 Oil is in cooling water, or water spurts back, or water level goes down............................................ 20-319 S-12 Oil pressure caution lamp lights up (Drop in oil pressure)................................................................ 20-320 S-13 Oil level rises (Water, fuel in oil) ....................................................................................................... 20-321 S-14 Water temperature becomes too high (Overheating) ....................................................................... 20-322 S-15 Abnormal noise is made ................................................................................................................... 20-323 S-16 Vibration is excessive ....................................................................................................................... 20-324
PC78MR-6
20-301
TROUBLESHOOTING
METHOD OF USING TROUBLESHOOTING CHART
METHOD OF USING TROUBLESHOOTING CHART This troubleshooting chart is divided into three sections: questions, check items, and troubleshooting. The questions and check items are used to pinpoint high probability causes that can be located from the failure symptoms or simple inspection without using troubleshooting tools. Next, troubleshooting tools or direct inspection are used to check the high probability causes to make final confirmation. [Questions] Sections (A) + (B) in the chart on the right corresponds to the items where answers can be obtained from the user. The items in (B) are items that can be obtained from the user, depending on the user's level. [Check items] The serviceman carries out simple inspection to narrow down the causes. The items under (C) in the chart on the right correspond to this. The serviceman narrows down the causes from information (A) that he has obtained from the user and the results of (C) that he has obtained from his own inspection. [Troubleshooting] Troubleshooting is carried out in the order of probability, starting with the causes that have been marked as having the highest probability from information gained from [Questions] and [Check items].
Causes
A
Questions
(1) (2) (3)
(a) (b) (c) (d)
C
Check items
(e) B
Troubleshooting
i
20-302
ii iii
PC78MR-6
TROUBLESHOOTING
METHOD OF USING TROUBLESHOOTING CHART
The basic method of using the troubleshooting chart is as follows. Items listed for [Questions] and [Check items] that have a relationship with the Cause items are marked with Q, and of these, causes that have a high probability are marked with w. Check each of the [Questions] and [Check items] in turn, and marked the Q or w in the chart for items where the problem appeared. The vertical column (Causes) that has the highest number of points is the most probable cause, so start troubleshooting for that item to make final confirmation of the cause. 1. For (Confirm recent repair history) in the [Questions] Section, ask the user, and mark the Cause column with E to use as reference for locating the cause of the failure. However, do not use this when making calculations to narrow down the causes. 2. Use the E in the Cause column as reference for [Degree of use (Operated for long period)] in the [Questions] section as reference. As a rule, do not use it when calculating the points for locating the cause, but it can be included if necessary to determine the order for troubleshooting.
PC78MR-6
1
Confirm recent repair history
2
Degree of use
Seiz ed t urbo cha Clog rger ged , int air c erfe lean renc Wor er e e n pi lem ston ent ring Clog , cyl ged inde , se r ized Imp injec rope tion r inj noz ectio Defe zle n tim ctive ing injec tion pum p (e xces si
ve in
jecti
on)
Causes
Operatred for long period
20-303
METHOD OF USING TROUBLESHOOTING CHART
TROUBLESHOOTING
•
Example of troubleshooting when exhaust gas is black Let us assume that [Clogged air cleaner] is taken to be the cause of black exhaust gas. Three symptoms have causal relationship with this problem: [Exhaust gas slowly became black], [Power slowly became weaker], and [Dust indicator is red]. If we look from these three symptoms to find the causes, we find that there is a relationship with five causes. Let us explain here the method of using this causal relationship to pinpoint the most probable cause.
S-7 Exhaust gas is black (incomplete combustion) General causes why exhaust gas is black • Insufficient intake of air • Improper condition of fuel injection • Excessive injection of fuel
Seiz
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
ed tu rboc Clog harg ged er, in air c terfe Wor lean re n pis er e ton leme nce Clog ring nt , cyli ged , n s d e er Imp ized rope injec r inje tion Defe ction nozz ctive le ti m ing injec Imp tion rope p ump r va Crus lve c ( exce lear hed ssiv ance , clo e inje Lea gge kage ction dm u ) o ff f le air b Defe r etwe ctive e c n onta Deff turb c ocha ectiv t of valv e inje e, va rger and ction lve s hea pum d eat p (ra ck, p lung er s eize d)
Causes
Confirm recent repair history Degree of use
Operated for long period
Questions
Suddenly became black Color of exhaust gas
Gradually became black Blue under light load
Engine oil must be added more frequently Power was lost
Suddenly Gradually
Non-specified fuel has been used Noise of interference is heard from around turbocharger Dust indicator is red Blow-by gas is excessive
Check items
Engine pickup is poor and combustion is irregular When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low Match marks on fuel injection pump are out of alignment Seal on injection pump has come off Clanging sound is heard from around cylinder head Exhaust noise is abnormal Muffler is crushed Leakage of air between turbocharger and head, loose clamp When turbocharger is rotated by hand, it is found to be heavy When air cleaner is inspected directly, it is found to be clogged
Troubleshooting
When compression pressure is measured, it is found to be low Speed of some cylinders does not change when operating on reduced cylinders When check is made using delivery method, injection timing is found to be incorrect Injection pump test shows that injection amount is incorrect When valve clearance is checked directly it is found to be outside standard value When muffler is removed, exhaust gas color returns to normal
20-304
Replace
Repair
Replace
Adjust
Replace
Adjust
Adjust
Replace
Replace
Clean
Remedy
Replace
When control rack is pushed, it is found to be heavy or does not return
PC78MR-6
TROUBLESHOOTING
METHOD OF USING TROUBLESHOOTING CHART
Five causes Step 1 Clarify the relationship between the three symptoms in the [Questions] and [Check items] section and the five Cause items in the vertical column.
Three symptoms
Step 2 Add up the total of and marks where the horizontal lines for the three symptoms and the vertical columns for the causes intersect. (1) Clogged air cleaner element: (2) Air leakage between turbocharger and head: (3) Clogged, seized injection nozzle: (4) Defective contact of valve, valve seat: (5) Worn piston ring, cylinder: Step 3 The calculation in Step 2 show that the closest relationship is with [Clogged air cleaner element]. Follow this column down to the troubleshooting area and carry out the troubleshooting item marked . The Remedy is given as [Clean], so carry out cleaning, and the exhaust gas color should return to normal.
PC78MR-6
20-305
TROUBLESHOOTING
S-1
S-1 Starting performance is poor (Starting always takes time) Possible causes of the engine not starting though exhaust gas being discharged. • Electrical system is defective. • Fuel supply is insufficient. • Air intake is insufficient. • Fuel selection is improper. (Under the ambient temperature of – 10°C or lower, use ASTM D975 No.1
n pis ton r Defe ing, cylin ctive der cont Clog act o ging f valv a ir cle e an Clog aner d va gibg elem lve s f u e eat ent l Clog filter ging , stra f in e e e d pu r Glow mp s plug train (inclu aer ding preheat ing c ircuit )
Causes
a Battery charging rate Ambient temperature
Charging rate
20°C 0°C –10°C
•
90 %
80 %
75 %
70 %
1.28 1.29 1.30
1.26 1.27 1.28
1.24 1.25 1.26
1.23 1.24 1.25
1.22 1.23 1.24
A battery can be used if the specific gravity shows 70% or higher charging rate shown in the above table. In cold weather, 75% or higher charging rate is required.
Wor
•
100 %
Questions
Confirm recent repair history Degree of use of machine
Operated for long period
Ease of starting
Gradually became worse Starts when warm
Preheat indicator lamp does not light up. Engine oil consumption became increased. Filters have not been replaced according to the operation manual. Non-specified fuel has been used for long. Dust indicator lamp is ON. Battery charge lamp is ON. Starter motor runs slowly. After engine started, some cylinders are cool when touched the exhaust manifold. Engine speed cannot be raised smoothly, and combustion is irregular.
Check items
Blow-by gas is excessive. Match marks on fuel injection pump are not matched. Mud is sticking to the fuel tank cap. When the engine is cranked by the starter motor; 1) Even if the injection pump sleeve nut is loosened, little fuel comes out. 2) Even if the fuel filter air bleeding plug is loosened, little fuel comes out. Leakage from the fuel piping Engine hunting (rotation is irregular). Compression pressure measurement found low pressure. Direct inspection of the air element found clogging. Troubleshooting
Direct inspection of the fuel filter and strainer found clogging. Direct inspection of the feed pump strainer found clogging. Heater mount section is not heated. Yes
Is voltage 26–30V between alternator terminal R and terminal E with engine at low idling?
No
Either specific gravity or voltage of the battery is low. Speed of some cylinders does not change when operating on reduced cylinders. When pushed, the control rack is heavy, or does not return. (Remove the blind cover at the rear of the pump. Plunger control sleeve does not move.)
20-306
Replace
Clean
Clean
Clean
Correct
Remedy
Replace
Direct inspection of the fuel cap found clogging. Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
PC78MR-6
PC78MR-6
Replace
Replace
Clean
Correct
Replace
Adjust
Replace
Replace
Replace
Replace Defe ctive alter Defe nato ctive r (ex a terna ltern Defe l reg ator ctive ulato (buil o r deg t-in r r typ Defe egula e) rade ctive d tor ty b injec a t t Injec pe) e tion ry tion nozz timin le Defe g fail tive u re injec Leak tion age, pum p (ra clog Clog ck a ging ged nd p , or a air b lung ir in reath Defe er st fuel uck) ctive er ho pipin f g le e ed p in Defe fuel ump ctive syst em boos t com pens ator canc el
TROUBLESHOOTING S-1
Causes
20-307
S-2
TROUBLESHOOTING
S-2 Engine does not start (1) Engine does not turn
Causes
Defe
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
ctive wirin Defe g of ctive star or d ting Defe eter circu iora ctive it t e s d ba tarti Brok ttery ng m en r otor in g g Defe ear ctive safe Defe ty re ctive lay o b r sa atte Defe fety ry re ctive swit lay ch b a ttery Defe ctive term i n f u a l co el cu Defe nne t sol ctive ction eno star id ting swit ch
General causes why engine does not turn • Internal parts of engine seized a If internal parts of the engine are seized, carry out troubleshooting for "Engine stops during operations". • Defective electrical system
Questions
Confirm recent repair history Degree of use of machine
Operated for long period
Horn does not sound Condition of horn when starting switch is turned ON Horn volume is low Speed of rotation is low When starting switch is turned to START, pinion moves out, but
Makes grating noise Soon disengages again Makes rattling noise and does not turn
When starting switch is turned to ON, there is no clicking sound
20-308
Replace
Replace
Replace
—
Replace
Remedy
Replace
Troubleshooting
Specific gravity of electrolyte, voltage of battery is low For the following conditions 1) - 5), turn the starting switch OFF, connect the cord, and carry out troubleshooting 1) When terminal B and terminal C of starting switch are connected, engine starts 2) When terminal B and terminal C of starting motor are connected, engine starts 3) When terminal B and terminal C of safety relay are connected, engine starts 4) When terminal of safety switch and terminal B of starting motor are connected, engine starts 5) There is no 24V between battery relay terminal b and terminal E When ring gear is inspected directly, tooth surface is found to be chipped Cannot be moved by hand even when linkage of fuel cut solenoid is disconnected
Replace
When battery is checked, battery electrolyte is found to be low
Replace
When starting switch is turned ON, linkage is not actuated
Troubleshooting of defective wiring in starting circuit
Battery terminal is loose
Replace
Check items
When starting switch is turned to START, pinion does not move out
PC78MR-6
TROUBLESHOOTING
S-2
(2) Engine turns but no exhaust smoke comes out (Fuel is not being injected) General causes why engine turns but no exhaust smoke comes out • Supply of fuel impossible • Supply of fuel is extremely small • Improper selection of fuel (particularly in winter) Causes
a Standards for use of fuel -4 -20
14 -10
32 0
50 10
68 20
86 F 30
ASTM D975 No. 2 ASTM D975 No.2 Diesel fuel
ASTM D975 No.1
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Brok en in jecti Defe on p ctive ump injec drive Seiz tion shaf ed, pum t, ke brok p (ra y en f Clog ck, p eed g ed lung p u f uel f mp er s Clog pisto ilter, eize ged d) n stra feed i n e Insu r pum fficie p s train nt fu Clog er el in ged tank , lea Clog king g ed fuel air b pipin Defe reat g her ctive h o le i fuel Imp n fu cut s rope el ta ol r f ue nk l use e n o i d d
AMBIENT TEMPERATURE
KIND OF FLUID
Questions
Confirm recent repair history Operated for long period Degree of use of machine Exhaust smoke suddenly stops coming out (when starting again) Replacement of filters has not been carried out according to Operation Manual Fuel tank is found to be empty There is leakage from fuel piping Mud is stuck to fuel tank cap When starting switch is turned ON, linkage is not actuated
Check items
When fuel filter is drained, fuel does not come out When engine is cranked with starting motor, 1) Injection pump coupling does no rotate. 2) No fuel comes out even when fuel filter air bleed plug is loosened 3) No fuel spurts out even when injection pump sleeve nut is loosened Rust and water are found when fuel tank is drained
Troubleshooting
Inspect injection pump directly When control rack is pushed, it is found to be heavy, or does not return Inspect feed pump directly When fuel filter, strainer are inspected directly, they are found to be clogged When feed pump strainer is inspected directly, it is found to be clogged When fuel cap is inspected directly, it is found to be clogged
PC78MR-6
Replace
Replace
Correct
Correct
Add
Clean
Clean
Replace
Replace
Remedy
Replace
Even though the linkage of the fuel cut solenoid is disconnected, it doesnot work
20-309
S-2
TROUBLESHOOTING
(3) Exhaust smoke comes out but engine does not start (Fuel is being injected)
ctive , bro ken v Defe alve ctive syste injec Wor m (v tion alve, n pis p u mp rocke ton ( rin g r Clog r leve a c k , cyl , plu ged r, etc inde nge f .) u e r line r stu Clog l filte ck) g ed r r, st rain feed er Clog pum ged p str air c aine Glow lean r er e plug leme (incl Defe n u t d ing p ctive r e -h or d Lea e e ating t e kage riora circu , clo te d it ) batt Clog ggin ery g, a ged ir in injec fuel Clog tion syst ged nozz em air b le, d Imp reat efec rope h tive er h r f ue spra ole i l use n fu y d el ta nk c ap
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Causes
Defe
General causes why exhaust smoke comes out but engine not start • Lack of rotating force due to defective electrical system • Insufficient supply of fuel • Insufficient intake of air • Improper selection of fuel and oil
Confirm recent repair history
Questions
Degree of use of machine
Operated for long period
Suddenly failed to start When engine is cranked, abnormal noise is heard from around head Engine oil must be added more frequently Non-specified fuel is being used Replacement of filters has not been carried out according to Operation Manual Rust and water are found when fuel tank is drained Dust indicator lamp is red Indicator lamp does not light up Starting motor cranks engine slowly
Check items
Mud is stuck to fuel tank cap When fuel lever is placed at FULL position, it does not contact stopper When engine is cranked with starting motor, 1) Little fuel comes out even when injection pump sleeve nut is loosened 2) No fuel comes out even when fuel filter air bleed plug is loosened There is leakage from fuel piping When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low
Troubleshooting
When fuel filter is drained, no fuel comes out Remove head cover and check directly When control rack is pushed, it is found to be heavy, or does not return When compression pressure is measured, it is found to be low When fuel filter, strainer are inspected directly, they are found to be clogged When feed pump strainer is inspected directly, it is found to be clogged When air cleaner element is inspected directly, it is found to be clogged Glow plug mount does not become warm Either specific gravity of electrolyte or voltage of battery is low When feed pump is operated, there is no response, or operation is too heavy Speed does not change when operation of certain cylinders is stopped
20-310
Clean
Clean
Correct
Replace
Correct
Clean
Clean
Clean
Replace
Replace
Remedy
Replace
When fuel cap is inspected directly, it is found to be clogged
PC78MR-6
S-3
TROUBLESHOOTING
S-3 Engine does not pick up smoothly (Follow-up is poor) General causes why engine does not pick up smoothly • Insufficient intake of air • Insufficient supply of fuel • Improper condition of fuel injction • Improper fuel used
air c lean er e leme f uel f Clog nt ilter, ged stra f e iner ed p Clog ump ged stra injec iner Seiz tion ed in nozz jectio l e , de Wor n pu fecti n pis mp ve s p t o pray lu n nge Seiz ring r , cyl ed t inde urbo r line char Imp rope ger, r r va inter lve c Clog fe re lear ged nce ance air b reat C lo g h er h ged , lea ole i Defe n fu king el ta ctive fuel nk c pipin cont ap act o g f val ve a nd v alve seat ged
Clog
Clean
ged C lo g
Clean
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Causes
Questions
Confirm recent repair history Operated for long period Degree of use of machine Replacement of filters has not been carried out according to Operation Manual Non-specified fuel is being used Engine oil must be added more frequently Rust and water are found when fuel tank is drained Dust indicator lamp is red Noise of interference is heard from around turbocharger Engine pick-up suddenly became poor Color of exhaust gas
Blue under light load Black
Check items
Clanging sound is heard from around cylinder head Mud is stuck to fuel tank cap There is leakage from fuel piping High idling speed under no load is normal, but speed suddenly drops when load is applied There is hunting from engine (rotation is irregular) When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low
Troubleshooting
Blow-by gas is excessive When air cleaner element is inspected directly, it is found to be clogged When fuel filter, strainer are inspected directly, they are found to be clogged When feed pump strainer is inspected directly, it is found to be clogged Speed does not change when operation of certain cylinders is stopped When control rack is pushed, it is found to be heavy, or does not return When compression pressure is measured, it is found to be low When turbocharger is rotated by hand, it is found to be heavy When valve clearance is checked directly, it is found to be outside standard value When fuel tank cap is inspected directly, it is found to be clogged
PC78MR-6
Replace
Correct
Clean
Adjust
Replace
Replace
Replace
Correct
Remedy
Clean
When feed pump is operated, operation is too light or too heavy
20-311
S-4
TROUBLESHOOTING
S-4 Engine stops during operations
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Causes Brok en, seiz ed p Brok iston en, seiz , con ed c Brok nect rank en d in g r shaf ynam od t be ic va Brok arin lve s en, g y s s e t i e z Brok m (v ed g en p alve ear , roc train ump ker le Brok a u xilia ver, en f ry e etc.) uel p q u Insu u i p mp m fficie e drive nt nt fu shaf C l og el in t, ke ged tank y fuel Clog filter ged , str aine feed r Brok pum en, p str seiz aine Clog ed f r eed ged pum , lea king p pis Clog fuel ton ged pipin air b g Defe reat her ctive hole injec in fu tion el ta pum nk p (ra ck, p lung er s tuck )
General causes why engine stops during operations • Seized parts inside engine • Insufficient supply of fuel • Overheating a If there is overheating and the engine stops, carry out troubleshooting for overheating.
Confirm recent repair history Degree of use of machine
Operated for long period
Questions
Abnormal noise was heard and engine stopped suddenly Condition when engine stopped
Engine overheated and stopped Engine stopped slowly There was hunting and engine stopped
Fuel level lamp lights up Fuel tank is found to be empty Replacement of filters has not been carried out according to Operation Manual Non-specified fuel is being used When feed pump is operated, operation is too light or too heavy Mud is stuck to fuel tank cap Engine rotates, but stops when power train is operated
Check items
Does not turn at all When it is attempted to turn by hand using barring tool
Turns in opposite direction Moves amount of backlash Shaft does not turn
Rust and water are found when fuel tank is drained Metal particles are found when oil is drained Remove oil pan and inspect directly
Troubleshooting
Remove head cover and inspect directly When gear train is inspected, it does not turn Rotates when pump auxiliary equipment is removed When fuel filter, strainer are inspected directly, they are found to be clogged When feed pump strainer is inspected directly, it is found to be clogged Inspect feed pump directly
20-312
Replace
Clean
Correct
Replace
Clean
Clean
Add
Replace
Replace
Replace
Replace
Replace
Remedy
Replace
When control rack is pushed, it is found to be heavy, or does not return
PC78MR-6
S-5
TROUBLESHOOTING
S-5 Engine does not rotate smoothly (Hunting)
ctive ope Defe ratio ctive n of adju gove Defe stme rnor ctive nt o f go o pera Low v erno tion idlin r of co g sp Insu n e t ro l r e d is fficie ack too nt fu low Clog el in g ed tank f e e d Clog pum ged p str fuel aine Clog f i lter, r ged, stra air in i ner Clog c ir cuit ged, betw air in een Clog circu fuel ged it t a nk betw air b an d een reat feed feed her pum pum hole p p an in fu d no el ta zzle nk
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Causes
Defe
General causes why engine does not rotate smoothly • Air in fuel system • Defective governor mechanism • Defective electric governor mechanism (engine with electric governor) a If hunting stops when electric governor rod is disconnected, carry out troubleshooting for the chassis.
Confirm recent repair history Degree of use of machine
Operated for long period
Questions
Occurs at a certain speed range Condition of hunting
Occurs at low idling Occurs even when speed is raised Occurs on slopes
Fuel tank is found to be empty Replacement of filters has not been carried out according to Operation Manual Rust, water are found when fuel tank is drained Leakage from fuel piping
Check items
When feed pump is operated, 1) No response, light, return is quick 2) No response, light, return is normal Engine speed sometimes rises too far Engine is sometimes difficult to stop Seal on injection pump has come off
Troubleshooting
When governor lever is moved it is found to be stiff When injection pump is tested, governor is found to be improperly adjusted When control rack is pushed, it is found to be heavy, or does not return When fuel cap is inspected directly, it is found to be clogged When feed pump strainer is inspected directly, it is found to be clogged
PC78MR-6
Clean
Correct
Correct
Clean
Clean
Add
Adjust
Adjust
Adjust
Remedy
Adjust
When fuel filter, strainer are inspected directly, they are found to be clogged
20-313
S-6
TROUBLESHOOTING
S-6 Engine lacks output (or lacks power) General causes why engine lacks output • Insufficient intake of air • Insufficient supply of fuel • Improper condition of fuel injection • Improper fuel used (if non-specified fuel is used, output drops) • Lack of output due to overtaking a If there is overheating and lack of output, carry out troubleshooting for overheating.
ged air c le a n ed t er e urbo leme char Wor nt ger, n pis inter ton r in g f Clog eren , cyl ged ce inde fuel r Clog f i lter, ged stra feed iner Clog pum ged p str i njec aine Seiz tion r ed in nozz j e le, d c t Imp i o n efec rope pum tive p pl u r va spra lve c Defe n g y er lear ctive a n c c onta e Ben ct of t fue valv l lev e an Clog er lin d va ged kage lve s , lea , de eat Clog king f e c tive ged fuel adju a p i i r p i b stme Defe ng reat her ctive nt hole boo in fu st co el ta mpe nk nsat or d iaph ragm Seiz
C log
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Causes
Confirm recent repair history Degree of use of machine
Questions
Power was lost
Operated for long period Suddenly Gradually
Engine oil must be added more frequently Replacement of filters has not been carried out according to Operation Manual Non-specified fuel is being used Dust indicator lamp is red Color of exhaust gas
Black Blue under light load
Noise of interference is heard from around turbocharger Blow-by gas is excessive Check items
Engine pickup is poor and combustion is irregular High idling speed under no load is normal, but speed suddenly drops when load is applied When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low There is hunting from engine (rotation is irregular) Clanging sound is heard from around cylinder head High idling speed of engine is low Leakage from fuel piping When air cleaner element is inspected directly, it is found to be clogged When turbocharger is rotated by hand, it is found to be heavy
Troubleshooting
When compression pressure is measured, it is found to be low When fuel filter, strainer are inspected directly, they are found to be clogged When feed pump strainer is inspected directly, it is found to be clogged Speed does not change when operation of certain cylinders is stopped When control rack is pushed, it is found to be heavy, or does not return When valve clearance is checked directly, it is found to be outside standard value When lever is placed at FULL position, it does not contact stopper When feed pump is operated, operation is too light or too heavy
20-314
Replace
Clean
Correct
Adjust
Replace
Adjust
Replace
Correct
Clean
Clean
Replace
Replace
Remedy
Clean
When fuel cap is inspected directly, it is found to be clogged
PC78MR-6
S-7
TROUBLESHOOTING
S-7 Exhaust smoke is black (Incomplete combustion) General causes why exhaust smoke is black • Insufficient intake of air • Improper condition of fuel injection • Excessive injection of fuel
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Seiz ed t u rbo Clog char ger, ged air c inter Wor lean fere n pis nce er e leme ton r in g Clog nt , c ge d ylind , sei er Imp zed rope r i n je i n j e c t i o nn Defe ction ctive timin ozzle i g n jecti Imp on p rope u mp r va lve c Crus (exc lear essi hed ance ve in , clo gge Lea jecti dm kage on) u f fler of a ir be Defe twee ctive n tu cont Defe rboc act o ctive harg f val er a injec ve a nd h tion nd v ead p um a l v e se p (ra at ck, p lung er s eize d)
Causes
Confirm recent repair history Degree of use of machine
Operated for long period Suddenly became black
Questions
Color of exhaust gas
Gradually became black Blue under light load
Engine oil must be added more frequently Power was lost
Suddenly Gradually
Non-specified fuel is being used Noise of interference is heard from around turbocharger Dust indicator lamp is red Blow-by gas is excessive
Check items
Engine pickup is poor and combustion is irregular When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low Timing lock on fuel injection pump does not match Seal on injection pump has come off Clanging sound is heard from around cylinder head Exhaust noise is abnormal Muffler is crushed Leakage of air between turbocharger and head, loose clamp When turbocharger is rotated by hand, it is found to be heavy When air cleaner is inspected directly, it is found to be clogged
Troubleshooting
When compression pressure is measured, it is found to be low Speed does not change when operation of certain cylinders is stopped When check is made using delivery method, injection timing is found to be incorrect Injection pump test shows that injection amount is incorrect When valve clearance is checked directly it is found to be outside standard value When muffler is removed, exhaust color returns to normal
PC78MR-6
Replace
Replace
Correct
Replace
Adjust
Adjust
Adjust
Replace
Replace
Clean
Remedy
Replace
When control rack is pushed, it is found to be heavy, or does not return
20-315
S-8
TROUBLESHOOTING
S-8 Oil consumption is excessive (or exhaust smoke is blue) a Do not run the engine at idling for more than 20 minutes continuously. (Both low and high idling)
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Brok en p iston Wor ring n pis ton ring Clog , cyli ged nde brea r line L ea t h e r r or kage brea f r o Lea m t h e o r ho kage i l f ilt se er o from r oil L ea oil p cool kage ipin g er from L ea oil d kage rain f rom p lug Brok oil p en o an o i l co r cylin Wor oler der n se hea a l at d Wor turb ine e n se al at n d Wor blow n, b er e roke nd n re Dus ar s Turb t suc e a ocha l, se ked al su rger Wor in fr om n va r f a ce intak lve ( e sy stem stem , gu ide) , bro ken seal
General causes why oil consumption is excessive • Abnormal combustion of oil • External leakage of oil • Wear of lubrication system
Causes
Questions
Confirm recent repair history Degree of use of machine
Operated for long period
Oil consumption suddenly increased Engine oil must be added more frequently Engine oil becomes contaminated quickly Exhaust smoke is blue under light load Amount of blow-by gas
Excessive None
Check items
Area around engine is dirty with oil There is oil in engine cooling water When exhaust pipe is removed, inside is found to be dirty with oil When turbocharger air supply pipe is removed, inside is found to be dirty with oil Oil level in damper chamber rises Clamps for intake system are loose
Troubleshooting
When compression pressure is measured, it is found to be low When breather element is inspected, it is found to be clogged with dirty oil There is external leakage of oil from engine Pressure-tightness test of oil cooler shows there is leakage Excessive play of turbocharger shaft Inspect rear seal directly When intake manifold is removed, dust is found inside
20-316
Correct
Correct
Correct
Replace
Replace
Replace
Correct
Correct
Correct
Correct
Clean
Replace
Remedy
Replace
When intake manifold is removed, inside is found to be dirty with oil
PC78MR-6
S-9
TROUBLESHOOTING
S-9 Oil becomes contaminated quickly
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
nd
Causes
Wor n pis ton r ing Clog , cyl g ed inde brea r line Clog ther r , bre g ed athe oil fi lter Wor r ho se n va lve, Clog valv ged e gu oil c ide oo le Clog r ged t urbo Defe char ctive ger seal drai Exh n pip at tu aust e rboc smo harg ke is er tu blac r b in k ee
General causes why oil becomes contaminated quickly • Entry of exhaust gas due to internal wear • Clogging of lubrication passage • Improper fuel • Improper oil used • Operation under excessive load
Questions
Confirm recent repair history Degree of use of machine
Operated for long period
Engine oil must be added more frequently Non-specified oil is being used Color of exhaust gas
Blue under light load Black None
Carry out troubleshooting for “Exhaust smoke is black”.
Check items
Excessive Amount of blow-by gas
When oil filter is inspected, metal particles are found When exhaust pipe is removed, inside is found to be dirty with oil Engine oil temperature rises quickly
When breather element is inspected directly, hose is broken or is found to be clogged with dirty oil When oil filter is inspected directly, it is found to be clogged When oil cooler is inspected directly, it is found to be clogged Turbocharger drain tube is clogged
PC78MR-6
Replace
Clean
Clean
Replace
Replace
Remedy
Clean
Excessive play of turbocharger shaft When safety valve is directly inspected, spring is found to be catching or broken Replace
Troubleshooting
When compression pressure is measured, it is found to be low
—
20-317
S-10
TROUBLESHOOTING
S-10 Fuel consumption is excessive General causes why fuel consumption is excessive • Leakage of fuel • Improper condition of fuel injection • Excessive injection of fuel
Defe ctive injec tion Defe pum ctive p (ex nozz cess Defe le ho ive in ctive lder jectio spra injec n) y Defe tion p ctive ump fuel p lu nger injec Exte tion rnal timin leak g age Defe from ctive fuel oil se pipin Defe al in g, fu ctive side el filt adju feed er stme pum nt of p (pis fuel ton) cont rol li nkag e
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Causes
Questions
Confirm recent repair history Degree of use of machine Condition of fuel consumption
Operated for long period More than for other machines of same model Gradually increased Suddenly increased
Exhaust smoke color
Black
Seal on injection pump has come off
Check items
There is irregular combustion When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low Match mark on injection pump is misaligned There is external leakage of fuel from engine Engine oil level rises and smells of diesel fuel Engine low idling and high idling speeds are high
Speed does not change when operation of certain cylinders is stopped When control rack is pushed, it is found to be heavy, or does not return When check is made using delivery method, injection timing is found to be incorrect Remove feed pump and inspect directly
20-318
Adjust
Correct
Correct
Adjust
Replace
Remedy
Replace
When engine speed is measured, low idling and high idling speeds are found to be high
Adjust
Troubleshooting
Injection pump measurement shows that injection amount is excessive
PC78MR-6
S-11
TROUBLESHOOTING
S-11 Oil is in cooling water, or water spurts back, or water level goes down General causes why oil is in cooling water • Internal leakage in lubrication system • Internal leakage in cooling system
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Brok en o il coo ler c Brok ore, en c O-rin ylind g er he Hole ad, h s ca used ea d g b aske Inter y pit nal c t ting rack s in cylin der b lock
Causes
Questions
Confirm recent repair history Degree of use of machine Oil level
Operated for long period Suddenly increased Gradually increased
Check items
Engine oil level has risen, oil is cloudy white
Troubleshooting
Hard water is being used as cooling water
Pressure-tightness test of oil cooler shows there is leakage
Excessive air bubbles inside radiator, spurts back
Pressure-tightness test of cylinder head shows there is leakage
PC78MR-6
Replace
Replace
Replace
Remedy
Replace
Remove oil pan and inspect directly
20-319
TROUBLESHOOTING
S-12
S-12 Oil pressure caution lamp lights up (Drop in oil pressure) General causes why oil pressure lamp lights up • Leakage, clogging, wear of lubricating system • Defective oil pressure control • Improper oil used (improper viscosity) • Deterioration of oil due to overheating a Standards for engine oil selection
Wor
Clog
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
ged oil fi lter n be arin g, jo Clog urna ged l stra iner C lo g insid ged e oil or b Brok roke pan en s uctio n oil pip Defe e ins n pip ctive i de o e br azin i l pa oil p Lack g n ump of o i l i n oil Defe pan ctive regu Defe lator ctive valv relie e Lea f val king ve , cru Defe shed ctive hydr aulic oil le Defe vel s pipin ctive enso g oil p r r essu Wat er, f r e s uel i enso n oil r
Causes
Questions
Confirm recent repair history Operated for long period Degree of use of machine Replacement of filters has not been carried out according to Operation Manual Caution lamp lights up Non-specified oil is being used Lights up at low idling Condition when oil pressure lamp lights up
Lights up at low, high idling Lights up on slopes
Check items
Sometimes lights up There is crushing, leakage from hydraulic piping (external) Oil level sensor lamp lights up When oil level in oil pan is inspected, it is found to be low Metal particles are found when oil is drained Metal particles are stuck to oil filter element
Carry out troubleshooting for “Oil level rises”.
Oil is cloudy white or smells of diesel oil
Remove oil pan and inspect directly Oil pump rotation is heavy, there is play There is catching of relief valve or regulator valve, spring or valve guide is broken When oil level sensor is replaced, oil level sensor lamp goes out
20-320
Replace
Replace
Correct
Adjust
Adjust
Add
Replace
Correct
Clean
Clean
Remedy
Clean
When oil pressure is measured, it is found to be within standard value Clean
Troubleshooting
When oil filter is inspected, it is found to be clogged
—
PC78MR-6
S-13
TROUBLESHOOTING
S-13 Oil level rises (Water, fuel in oil) a If there is oil in the cooling water, carry out troubleshooting for “Oil is in cooling waterE
Questions
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Brok en o i l co oler Defe core ctive , Onozz ring Brok le ho en cy lder linde slee r hea Wor ve d, he n, d ad ga ama sket ged Defe (prec r ear ctive ombu seal pum stion Defe s u p rfac cham auxi ctive e ber) l i a r p y art i Defe e q uipm nsid ctive e inj e n t t herm ectio seal Hole n pu osta s ma t mp de b Crac y pit ks in ting side cylin der bloc k
General causes why oil level rises • Water in oil (milky white) • Fuel in oil (diluted, and smells of diesel fuel) • Entry of oil from other component
Causes
Confirm recent repair history Degree of use of machine
Operated for long period
There is oil in radiator cooling water Exhaust smoke is white When engine is first started, drops of water come from muffler Leave radiator cap open. When engine is run at idling, an abnormal number of bubbles appear, or water spurts back Water pump breather hole is clogged with mud
Check items
When water pump breather hole is clean, water comes out Oil level goes down or damper chamber Oil level goes down in hydraulic tank Engine oil smells of diesel fuel Fuel must be added more frequently Water temperature is low Pressure-tightness test of oil cooler shows there is leakage Troubleshooting
Pressure-tightness test of cylinder head shows there is leakage When compression pressure is measured, it is found to be low Inspect rear seal directly When pump auxiliary equipment is removed, seal is found to be damaged Remove injection pump and inspect directly Defective contact with thermostat seal valve
PC78MR-6
Replace
Replace
Correct
Replace
Replace
Correct
Replace
Replace
Remedy
Replace
Remove oil pan and check directly
20-321
S-14
TROUBLESHOOTING
S-14 Water temperature becomes too high (Overheating) General causes why water temperature becomes too high • Lack of cooling air (deformation, damage of fan) • Drop in heat dissipation efficiency • Defective cooling circulation system • Rise in oil temperature in power train a Carry out troubleshooting for chassis.
Brok en w ater Clog p um ged p , cru shed Clog ged radia radi tor f ator Defe ins core ctive t h Defe erm osta ctive t (do wate es n Lack r te m ot o of co p pen erat o ling ) ure Fan wate gau belt ge r slipp Clog ing, ged worn , bro fan ken Defe pulle oil c ctive y o o p ler ress Brok ure en c valv ylind e Hole er h s ma ead , he de b ad g y pit aske ting t
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Causes
Confirm recent repair history
Questions
Degree of use of machine Condition of overheating
Operated for long period Suddenly overheated Always tends to overheat
Water temperature gauge
Rises quickly Does not go down from red range
Radiator water level sensor lights up Fan belt whines under sudden load Cloudy white oil is floating on cooling water Cooling water flows out from overflow hose
Check items
Excessive air bubbles inside radiator, water spurts back Engine oil level has risen, oil is cloudy white There is play when fan pulley is rotated Radiator shroud, inside of underguard are clogged with dirt or mud When light bulb is held behind radiator, no light passes through Water is leaking because of cracks in hose or loose clamps
Troubleshooting
When belt tension is inspected, it is found to be loose Temperature difference between top and bottom radiator tanks is excessive Temperature difference between top and bottom radiator tanks is slight When water filler port is inspected, core is found to be clogged When function test is carried out on thermostat, it does not open even at cracking temperature When water temperature is measured, it is found to be normal When oil cooler is inspected directly, it is found to be clogged When measurement is made with radiator cap tester, set pressure is found to be low When compression pressure is measured, it is found to be low
20-322
Replace
Replace
Replace
Replace
Correct
Add
Replace
Replace
Correct
Correct
Remedy
Replace
Remove oil pan and inspect directly
PC78MR-6
S-15
TROUBLESHOOTING
S-15 Abnormal noise is made a Judge if the noise is an internal noise or an external noise.
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Exc essi ve w ear Seiz of p ed t iston urbo char Miss ring , cyl ger, ing, inde inter seiz r line fere ed b Clog nce r ushi ged ng Defe , seized ctive injec tion injec Defe nozz tion ctive le p um injec p (ra Defo tion ck, p rme pum l ung d fa p (e er s n, fa Defe xces eize n be ctive d) s ive i lt int a d njec justm erfe Brok tion) renc en d e n t of e ynam valv ic va Imp e cle rope lve s aran ystem r ge ce ar tr Lea (valv kage ain b e, ro ackl of a cker ash ir be Defe lever twee ct ins , etc ide m n tu .) rboc uffle harg r (div er a iding nd h boar ead d ou t of p ositio n)
General causes why abnormal noise is made • Abnormality due to defective parts • Abnormal combustion • Air sucked in from intake system
Causes
Questions
Confirm recent repair history Degree of use of machine
Operated for long period
Condition of abnormal noise
Gradually occurred Suddenly occurred
Non-specified fuel is being used Engine oil must be added more frequently Color of exhaust gas
Blue under light load Black
Metal particles are found in oil filter Blow-by gas is excessive Noise of interference is heard from around turbocharger Check items
Engine pickup is poor and combustion is abnormal When exhaust manifold is touched immediately after starting engine, temperature of some cylinders is low Seal on injection pump has come off Abnormal noise is loud when accelerating engine Clanging sound is heard from around cylinder head Leakage of air between turbocharger and head, loose clamp Vibrating noise is heard from around muffler When compression pressure is measured, it is found to be low When turbocharger is rotated by hand, it is found to be heavy
Troubleshooting
Remove gear cover and inspect directly Speed does not change when operation of certain cylinders is stopped When control rack is pushed, it is found to be heavy, or does not return Injection pump test shows that injection amount is incorrect Fan is deformed, belt is loose When valve clearance is checked, it is found to be outside standard value Remove cylinder head cover and inspect directly
PC78MR-6
Replace
Correct
Correct
Replace
Adjust
Correct
Adjust
Replace
Replace
Replace
Replace
Remedy
Replace
When muffler is removed, abnormal noise disappears
20-323
S-16
TROUBLESHOOTING
S-16 Vibration is excessive
General causes why vibration is excessive • Defective parts (abnormal wear, breakage) • Improper alignment • Abnormal combustion
Legend : Possible causes (judging from Questions and check items) : Most probable causes (judging from Questions and check items) : Possible causes due to length of use (used for a long period) : Items to confirm the cause.
Causes Wor n co nne cting Wor n ba rod, lanc main Loo er, c bea se e am ring ngin bush em Brok in g oun en p t ing b art i nsid olts, Imp e ou rope brok tput r ge en c ar tr shaf ushi Defe ain b t (da ctive on mpe ackl dyna Defe mic v ash r) a ctive lve s ystem injec (valv tion e, roc pu m ker le p (e ver, e xces tc. st sive uck) injec tion)
a If there is abnormal noise together with the vibration, carry out troubleshooting also for “Abnormal noise is made”
Questions
Confirm recent repair history Degree of use of machine Condition of vibration
Operated for long period Suddenly increased Gradually increased
Non-specified oil is being used Metal particles are found in oil filter Metal particles are found when oil is drained
Check items
Oil pressure is low at low idling Vibration occurs at mid-range speed Vibration follows engine speed Exhaust smoke is black Seal on injection pump has come off
Troubleshooting
Remove oil pan and inspect directly Remove side cover and inspect directly Inspect directly for loose engine mounting bolts, broken cushion Inspect inside of output shaft (damper) directly Remove front cover and inspect directly Remove head cover and inspect directly
20-324
Adjust
Replace
Correct
Replace
Replace
Replace
Remedy
Replace
Injection pump test shows that injection amount is incorrect
PC78MR-6
TROUBLESHOOTING OF COMMUNICATION SYSTEM (N MODE) N-1 Defective communication ................................................................................................................... 20-402
a When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the service code "E" is not displayed, the condition has returned to normal. a If the starting switch was turned OFF after the trouble occurred, turn the starting switch ON and check that the service code displays "E" at the head. (If "E" is not displayed, the condition has returned to normal.) a Before carrying out troubleshooting, check that all the related connectors are properly inserted. a Always connect and disconnected connectors before going on to the next step. PC78MR-6
20-401
N-1
TROUBLESHOOTING
N-1 Defective communication Cause
Remedy
1 NO
Is operation of monitor display switch normal?
YES
• Turn starting switch ON • Min. 0.75 V • Disconnect M96 and measure voltage on wiring harness side
Condition is normal
—
Defective controller
Replace
2 NO
Is voltage between M96 (Female) (21) – chassis ground normal?
YES
3 Is resistance between P02 (Female) (9), (10) – M96 (Female) (21) normal?
YES
NO
Disconnection or defective contact in Repair or wiring harness between P02 (Female) replace (9), (10) – M96 (Female) (21) Defective monitor panel
Replace
If the communication becomes defective, the following troubles occur. • The working mode cannot be changed. • The travel speed cannot be changed with the panel switches. • The monitor lamp does not light up when the one-touch slow-down mechanism is turned on. • Normal figures are not displayed on the display and service meter unit. • A mode cannot be selected. N-1 Electrical circuit diagram of each system
20-402
PC78MR-6
TROUBLESHOOTING FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) (E MODE) Precautions for troubleshooting for controller (governor control system).................................................... 20-502 Action taken by controller when trouble occurs and problems on machine ............................................... 20-504 Judgment table for controller (governor control system) and engine .......................................................... 20-506 E-1 Controller power supply is defective (LED of controller is turned off)................................................. 20-508 E-2 [E323] (Short circuit in accelerator relay system) is displayed ........................................................... 20-509 E-3 [E325] (Short circuit in decelerator relay system) is displayed........................................................... 20-510 E-4 [E328] (Stall of motor) is displayed......................................................................................................20-511 E-5 [E227] (Trouble in engine speed sensor) is displayed........................................................................ 20-513 E-6 One-touch slow-down mechanism does not work.............................................................................. 20-514 E-7 Engine does not start ......................................................................................................................... 20-515 a) [E304] Short circuit in engine stop solenoid relay system is displayed .......................................... 20-515 b) [E314] Disconnection in engine stop solenoid relay system is displayed ...................................... 20-515 c) Engine stop solenoid system.......................................................................................................... 20-516 d) Starting system............................................................................................................................... 20-518 E-8 Engine does not stop.......................................................................................................................... 20-522
PC78MR-6
20-501
TROUBLESHOOTING
PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (GOVERNOR CONTROL SYSTEM)
PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) 1) Precautions to be taken when trouble is repaired by itself 1) When a trouble is repaired by itself. 2) When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the service code is not displayed or the monitor displays normally, the same trouble will occur again probably. Accordingly, follow up the condition of the machine sufficiently. 3) After finishing troubleshooting, be sure to delete the saved service code. 2) Handling of function of saving service code When displaying a saved service code for troubleshooting, "take the notes of the all displayed items and delete those items", then reproduce the trouble and start the troubleshooting according to the service code displayed at this time. (Troubles caused by wrong operation, disconnection of a connector, etc. may be saved in the memory. In this case, you can avoid unnecessary work by performing the above operation.)
20-502
PC78MR-6
TROUBLESHOOTING
ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE
ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE User Code
Service Code
Troubled System
E323
Short circuit in accelerator relay system
E325
Short circuit in decelerator relay system
E05
E328
—
E304 E314
Stall of motor (When burn preventive function of motor operates)
Contents of Trouble 1) Short circuit in wiring harness between M97 pin 25 – K32 pin 1. 2) Short circuit in relay K32. 1) Short circuit in wiring harness between M97 pin 35 – K33 pin 1. 2) Short circuit in relay K33. 1) 2) 3) 4)
Short circuit of M97 pin 19 with power source. Short circuit of M97 pin 29 with power source. Short circuit of M97 pin 39 with power source. Trouble in motor.
1) Short circuit or disconnection in wiring harness between M97 (4) – M36 (1). 2) Disconnection in wiring harness between Disconnection engine stop solenoid relay system M36 (2) – chassis ground. 3) Trouble in M36 relay. Short circuit in engine stop solenoid relay system
When the motor is normal, its condition can be monitored as shown below.
•
•
•
•
•
•
When fuel control dial is operated (Slow o Full) Displayed code [1024] : (2), (3), (4), (6), light up and motor operates, then (2), (3), (4), (6) go off and motor stops (Only (4) keeps lighting up). When fuel control dial is operated (Full o Slow) Displayed code [1024] : While only (4) is lighting up, (1), (3), (5) light up and motor operates, then all lamps go off and motor stops. In E-mode (When fuel control dial is at FULL Displayed code [1024] : While only (4) is lighting up, (3), (5) light up and position) motor operates, then (2) lights up and (3), (5) go off and motor stops (Only (2) and (4) keep lighting up). When E-mode is changed to standard motor Displayed code [1024] : While only (2), (4) are lighting up, (3), (6) light up and (When fuel control dial is at FULL position) motor operates, then (2), (3), (6) go off and motor stops (Only (4) keeps lighting up). When one-touch slow-down mechanism is Displayed code [1024] : While only (4) is lighting up, (3), (5) light up and turned on (When fuel control dial is at FULL motor operates, then (2) lights up and (3), (4), (5) go position) off and motor stops (Only (2) keeps lighting up). Displayed code [1026] : When one-touch slow-down switch is turned on, (1) lights up (This is same as in resetting operation). When one-touch slow-down mechanism is Displayed code [1024] : While only (2) is lighting up, (3), (6) light up and turned off (When fuel control dial is at FULL motor operates, then (4) lights up and (2), (3), (6) go position) off and motor stops (Only (4) keeps lighting up).
20-504
PC78MR-6
ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE
TROUBLESHOOTING
Action taken by controller when trouble occurs Between M97 pin 25 – chassis ground: Min.: 1 Mz K32 pin 1 If trouble is detected, motor Resistance between K32 relay pin 1 – pin 2: 290 z ± 10% drive relay output, accelerator Resistance between K32 relay pin 1, 2 – pin 3, 5, 6 relay output, and decelerator : Min. 1 Mz relay output are stopped. Between M97 pin 35 – chassis ground: Min. 1 Mz K33 pin 1 Resistance between K33 relay pin 1 – pin 2: 290 z ± 10% Resistance between K33 relay pin 1, 2 – pin 3, 5, 6 : Min. 1 Mz Normal condition
Problems on machine 1. Fuel control dial cannot be operated (For acceleration and deceleration). 2. One-touch slow-down mechanism cannot be operated. 3. When working mode is changed, engine speed does not change.
Motor starts and stops from slow to full and from full to slow If accelerator, decelerator, or • in 2 seconds. one-touch slow-down mechanism works for more than 10 seconds, motor drive relay output, accelerator relay output, • and decelerator relay output are stopped. Relay M97 (female)
M36 (male)
Resistance
(4) – Chassis ground
(1) – (2)
68 z ± 10%
Stop solenoid output is stopped.
When signal system is troubled Motor operates but stalls soon. Then, it does not operated even if dial is moved. When motor is troubled Motor stalls from the first, then it does not operate even if dial is moved. 1. Stop solenoid cannot be pulled (Engine cannot be started).
Engine governor control system
PC78MR-6
20-505
TROUBLESHOOTING
JUDGMENT TABLE FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) AND ENGINE
JUDGMENT TABLE FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) AND ENGINE Controller and Engine
User Code
Engine does not start easily
2
Engine does not start
3
Engine speed does not rise sharply (Does not follow up accelerator pedal)
4
Engine stops
5
Engine hunts
6
Engine output (Power) is low
7
Exhaust gas color is bad (Imperfect combustion)
8
Much oil is consumed (or exhaust gas color is bad)
9
Oil becomes dirty soon Much fuel is consumed
11
Cooling water contains oil or blows back or its level lowers
12
Oil pressure caution lamp lights up Oil level rises
14
Water temperature rises too high (Overheating)
15
Abnormal sound is heard
16
Many vibrations are made
q
17
Engine speed does not follow up throttle valve
q
q
q
q
One-touch slow-down mechanism does not work
q
q
q
q
19
When working mode is changed, engine speed does not change
q
q
q
q
20
Engine does not stop
—
—
—
—
Decelerator relay output
Accelerator relay output
Auto deceleration signal 1024
q
q
E-1 E-2 E-3 E-4 E-7 E-7 E-5
Diagnosis code displayed when trouble is detected by monitoring or with machine monitor
Deceleration signal
Trouble in engine speed sensor system
Monitoring Code
314 227 323 325 328 (304 2) ( 2)
18
Diagnosis code displayed when service code is displayed
Short circuit in engine stop solenoid relay Disconnection in engine stop solenoid relay
Stall of motor
—
q
10
13
Short circuit in decelerator relay system
E05
Service Code 1
Short circuit in accelerator relay system
Trouble in controller power supply
Self-diagnosis Display
Acceleration signal
Items Checked/Inspected by monitoring
—
—
—
—
—
—
—
—
—
—
—
q: Items corresponding to service codes. Q: Items checked by monitoring or with machine monitor. : Items checked by monitoring.
20-506
PC78MR-6
TROUBLESHOOTING
JUDGMENT TABLE FOR CONTROLLER (GOVERNOR CONTROL SYSTEM) AND ENGINE
Is value in red range?
Diagnosis code displayed when service code is not displayed
95 Series
Min. 105 °C
Engine water temperature voltage
Engine speed
One-touch slow-down signal
Items Items checked/ inspected inspected by with machine monitoring monitor
Acceleration Signal 1026 1010 0041
108 (S-1) E-8 (S-2) (S-3) (S-4) (S-5) (S-6) (S-7) (S-8) (S-9) (S-10) (S-11) (S-12) (S-13)
Q
(S-14) (S-15) (S-16) E-4 E-6 E-4, E-5 E-8
—
—
—
—
—
—
—
M-2
PC78MR-6
20-507
E-1
TROUBLESHOOTING
E-1 Controller power supply is defective (LED of controller is turned off) a Check that fuse 20 is not broken. a Carry out the following troubleshooting when the starting motor revolves normally (If the starting motor does not revolve, see E-8, 19). Cause
Remedy
1 • Turn starting switch ON • 20 – 30 V
Is voltage between M96 (Female) (1), (11) NO – (21), (31), (32), (33), chassis ground normal?
YES
Defective controller
Replace
2 • Turn starting switch ON • 20 – 30 V
Is voltage between fuse 20 and chassis ground normal?
YES
NO
Disconnection or defective Repair or contact in wiring harness between fuse 20 – battery relay terminal B replace Disconnection or defective Repair or contact in wiring harness between fuse 20 – M97 (Female) (1), (11) replace
E-1 Electrical circuit diagram of each system
20-508
PC78MR-6
E-2
TROUBLESHOOTING
E-2 [E323] (Short circuit in accelerator relay system) is displayed Cause
Remedy
1 • Turn starting switch ON • Operate dial
NO
Is voltage between M97 (Female) (25) – (23) normal?
YES
Defective controller
Replace
Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (25) – K32 (Female) (1)
Repair or replace
Defective Relay
Repair or replace
2 • Disconnect M97 and K32 • Min. 1 Mz
Is resistance between M97 (Female) (25) and chassis ground normal?
YES
NO
If the wiring harness between M97 (25) – K34 (1) is shorted to the coil actually, the controller output is cut out. Accordingly, if [E323] is displayed, the controller is defective. E-2 Electrical circuit diagram of each system
PC78MR-6
20-509
E-3
TROUBLESHOOTING
E-3 [E325] (Short circuit in decelerator relay system) is displayed Cause
Remedy
1 • Turn starting switch ON • Operate dial (to lower)
NO
Is voltage between M97 (Female) (35) – (23) normal?
YES
Defective controller
Replace
Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (35) – K33 (Female) (1)
Repair or replace
Defective Relay
Repair or replace
2 • Disconnect M97 and K33 • Min. 1 Mz
Is resistance between M97 (Female) (35) – chassis ground normal?
NO
YES
If the wiring harness between M97 (35) – K33 (1) is shorted to the coil actually, the controller output is cut out. Accordingly, if [E325] is displayed, the controller is defective. E-3 Electrical circuit diagram of each system
20-510
PC78MR-6
E-4
TROUBLESHOOTING
E-4 [E328] (Stall of motor) is displayed a Stall of the motor ias displayed when the motor does not follow up the operation of the dial in 10 seconds. In this period, the input signal and relay output are checked by monitoring. Cause
Remedy
1
For state of bit, see Action taken by controller when trouble occurs and problems on machine.
Is monitored value normal?
• Turn starting switch ON • Max. 4 A when normal When dial is raised (1) side: (+), (4) side: (-) When dial is lowered (1) side: (-), (4) side: (+)
Is current between K27 (Female) (1) NO (Motor (+) and (4) (Motor (-) normal?
NO
YES
2
YES
• Resistance between (1) – (2) of each relay: 290 z ± 10% • Operation of each relay (when starting switch is ON) When in neutral, (3) – (6) are connected. When dial is raised, K32 (3), (5) are connected. When dial is lowered, K33 (3), (5) are connected.
Do relay of K32, K33 operate normally?
• Disconnect M97 and K27. • Resistance between pins: Max. 1 z • Resistance between pin and chassis and ground: Min. 1 Mz
• Is resistance between M97 (Female) (19) – K27 (Female) (5), between M97 (29) – K27 NO (Female) (6), between M97 (Female) (39) – K27 (Female) (3) normal? Is resistance between each wiring harness and chassis ground normal?
Defective motor (Drive system)
Replace motor
Defective relay
Replace
3 NO
YES Disconnection or defective contact in wiring harness between Repair or K27 (Female) (1), (4) – K32 replace (Female) (3), K33 (Female) (3)
4 Disconnection or defective contact in wiring harness between Repair or M97 (Female) (19), (29), (39) – replace K27 (Female) (5), (6), (3)
YES • Turn starting switch ON • When dial is raised Between K97 (19), (39) – (23): 24 V • When dial is lowered (slowed) Between M97 (29) – (23): 24 V
PC78MR-6
5 When dial is operated, is each input NO signal normal?
Defective motor (Signal system)
Replace
Defective controller
Replace
YES
20-511
TROUBLESHOOTING
E-4
E-4 Electrical circuit diagram of each system
20-512
PC78MR-6
E-5
TROUBLESHOOTING
E-5 [E227] (Trouble in engine speed sensor) is displayed Cause 1
• When starting switch is OFF: 0 • When engine speed is +5
slow: 113 0 • When engine speed is at full throttle: 202 ± 5
Remedy
NO
Is monitored engine speed normal?
YES Defective controller
Replace
Defective engine speed sensor
Repair or replace
2 • Disconnect M16 • 500 – 1,000 z
Is resistance between M16 (Male) (1) – (2) NO normal?
YES • Disconnect M16 • 500 – 1,000 z
Is resistance between M96 (Female) (39) – (40) normal?
YES
3 NO
Disconnection or defective contact in wiring harness between Repair or M96 (Female) (39) – M16 replace (Female) (1), (2) Defective installation of engine speed sensor
Test/Adjust
E-5 Electrical circuit diagram of each system
PC78MR-6
20-513
E-6
TROUBLESHOOTING
E-6 One-touch slow-down mechanism does not work Cause
Remedy
1 NO
Does deceleration monitor light up normally?
YES
• Disconnect K18 • When switch is ON: Max. 1z When switch is OFF: Min. 1 Mz • Disconnect K18 • Turn starting switch ON • 20 – 30 V
See troubleshooting in E-5
—
Defective one-touch decelerator switch
Replace lever assembly
2 Is resistance between K18 (Male) (1) – (2) NO normal?
YES Is voltage between K18 (Male) (1) – chassis ground normal?
YES
3 NO
Disconnection or defective contact in wiring harness between Repair or K18 (Female) (1) – fuse (11) or replace breakage of fuse (11) Disconnection or defective contact in wiring harness between Repair or K18 (Female) (2) – M97 (Female) replace (9)
E-6 Electrical circuit diagram of each system
20-514
PC78MR-6
E-7
TROUBLESHOOTING
E-7 Engine does not start a a a a a) b)
The signals from battery relay terminal M on the monitor screen, etc. must be normal. Carry out the following troubleshooting when the starting motor does not revolve. Before carrying out the troubleshooting, check that fuses 12, 14, 15, and 20 are normal. Lock the PPC hydraulic lock switch. (Raise the work equipment lever stand.) [E304] Short circuit in engine stop solenoid relay system is displayed [E314] Disconnection in engine stop solenoid relay system is displayed Cause
• Disconnect M97. • Resistance between M97 (female) (4) – chassis ground: 68 z ± 10%
• Disconnect M36. • Resistance between M36 (male) (1) – (2): 68 z ± 10% • Resistance between M36 (male) (1), (2) – chassis ground: Min. 1 Mz • Disconnect D26 (with M36 disconnected). • Resistance between M97 (female) (4) – chassis ground: Min. 1 Mz
Remedy
1 NO
Is resistance between M97 (female) (4) – chassis ground normal?
YES
Defective controller
Replace
Defective stop solenoid relay
Replace
Defective wiring harness (Grounding fault)
Repair or replace
Defective diode D26
Replace
2 Is resistance between stop solenoid relay NO M36 (male) (1) – (2) and between each pin and chassis ground normal?
YES
3 Is resistance between M97 (female) (4) – chassis ground normal?
YES
NO
E-7 a), b) Electrical circuit diagram of each system
PC78MR-6
20-515
E-7
TROUBLESHOOTING
c) Engine stop solenoid system a Check that fuse 15 is normal. a Check that service codes [E304] and [E314] are not recorded in the history. Cause
Remedy
1 See TESTING AND ADJUSTING
NO
When engine stop solenoid linkage is adjusted, does engine start?
YES
Defective adjustment of linkage
Adjust
2 • 20 – 29 V • Turn starting switch ON
YES • Max. 1 z • Turn starting switch OFF • Disconnect T8
3
Is resistance between engine stop solenoid terminal GND – chassis ground normal?
YES • 20 – 29 V • Disconnect PULL terminal. • For only 3 seconds after starting switch is turned ON.
NO
Is voltage between engine stop solenoid terminal – chassis ground normal?
NO
Disconnection or defective contact in wiring harness between Repair or engine stop solenoid terminal replace GND – chassis ground
4
Is voltage between engine stop solenoid PULL terminal and chassis ground normal?
NO
YES
Disconnection or defective contact in wiring harness between Repair or engine stop solenoid PULL terminal – fusible link M26 (male) replace (2) Defective engine stop solenoid
Replace
5 • 20 – 29 V • Turn starting switch ON
NO
Is voltage between outlet of fuse (15) – chassis ground normal?
YES
Disconnection or defective contact in wiring harness between Repair or outlet of fuse (15) – M3 (3) – replace solenoid terminal HOLD
6 • 20 – 29 V • Turn starting switch ON
Is voltage between starting switch terminal NO ACC – chassis ground normal?
YES
20-516
Defective starting switch (Between B – ACC)
Replace
Disconnection or defective contact in wiring harness between Repair or starting switch terminal ACC – replace inlet of fuse (15)
PC78MR-6
TROUBLESHOOTING
E-7
E-7 c) Electrical circuit diagram of each system
PC78MR-6
20-517
E-7
TROUBLESHOOTING
d) Starting System Cause
Remedy
1 Are battery voltage and specific gravity of NO battery fluid normal?
• Min. 24 V • Specific gravity: Min. 1.26
YES
Charge or replace
2 NO
When starting switch is turned OFF, does battery relay make sound?
• Turn starting switch OFF
Insufficient battery capacity
YES
3 Is engaging sound of starting motor pinion NO heard?
YES
4 Is voltage between starting motor terminal NO B – chassis ground normal?
• Turn starting switch ON • 20 – 29 V
YES
Defective contact in wiring harness between battery (+) terminal – battery relay Repair or terminal B – battery relay replace terminal M – starting motor terminal B (including battery relay) Defective starting motor (Body)
Repair or Replace
Defective starting switch (Between terminals B and C)
Replace
Defective starting motor (Electromagnetic switch)
Repair or replace
5 • Turn starting switch to START position. • 20 – 29 V
Is voltage between starting switch terminal NO C and chassis ground normal?
YES
6
Is voltage between safety relay terminal S NO – chassis ground normal?
Conditions are same as 5
YES
7 Is voltage between starting motor terminal NO C – chassis ground normal?
Conditions are same as 5
YES
8 Is voltage between safety relay terminal C NO – chassis ground normal?
Conditions are same as 5
YES
9 Is voltage between safety relay terminal R NO – chassis ground normal?
• Turn starting switch ON • Max. 13 V
YES To page 20-520
Disconnection or defective contact in wiring harness Repair or between starting motor replace safety relay terminal C – starting motor terminal C
Defective alternator
Repair or replace
Defective starting motor safety relay
Replace
To page 20-519
20-518
PC78MR-6
E-7
TROUBLESHOOTING
From page 20-518, 6
Cause
Remedy
10 • 20 – 29 V • Turn starting switch to START.
NO
Is voltage between V2 (8) – chassis ground normal?
Disconnection or defective contact in wiring harness Repair or between safety relay terminal S replace – M30 (1) – M5 (4) – V2 (Female) (8)
YES
11 • 20 – 29 V • Turn starting switch to START
NO
Is voltage between V2 (7) – chassis ground normal?
YES
Disconnection or defective contact in wiring harness between V2 (Male) (7) – (8)
12 • 20 – 29 V • Turn starting switch to START
NO
Is voltage between K23 (3) – chassis ground normal?
Disconnection or defective contact in wiring harness Repair or between K23 (Female) (3) – V3 replace (Female) (3)
YES
13 • 20 – 29 V • Turn starting switch to START
YES • 20 – 29 V • Turn starting switch ON • Lock PPC lock switch
14
Disconnection or defective contact in wiring harness between K23 (Female) (5) – K51 (6) – starting switch terminal C
Repair or replace
NO
Is voltage between K23 (1) – chassis ground normal?
YES • Max. 1 z • Turn starting switch ON • Disconnect K23
NO
Is voltage between K23 (5) – chassis ground normal?
15
Is resistance between K23 (Female) (2) – NO chassis ground normal?
YES
Disconnection or defective Repair or contact in wiring harness between K23 (Female) (2) – M1 replace (2) – chassis ground Defective K23 relay
Replace
Disconnection or defective contact in wiring harness between K28 (Male) (3) – K23 (Female) (1) – chassis ground
Repair or replace
16 • 20 – 29 V • Turn starting switch ON • Lock PPC lock lever
Is voltage between k28 (3) – chassis ground normal?
YES
NO
To page 20-520
PC78MR-6
20-519
E-7
TROUBLESHOOTING
Cause
From page 20-519, 16
Remedy
17 • 20 – 29 V • Turn starting switch ON
NO
Is voltage between K28 (1) – chassis ground normal?
YES
Disconnection or defective contact in wiring harness between K28 (Male) (1) – fuse (14)
Repair or replace
Disconnection or defective contact in wiring harness between K28 (Female) (3) – K23 (Female) (1)
Repair or replace
From page 20-518, 2
Cause 18 • Connect (-) pin of tester to (-) terminal of battery • 20 – 29 V
Is voltage at starting switch terminal B normal?
YES • Disconnect terminal B • Turn starting switch to START
NO
19
Is there continuity between starting switch NO terminals B – BR?
YES
20
• Set tester in diode range and apply (+) to starting switch and (-) to battery relay • Disconnect both starting switch and battery relay
Is there continuity between starting switch NO terminal BR – battery relay terminal BR?
• Turn starting switch OFF
Is there continuity between chassis ground and battery relay terminal B?
YES
YES
20-520
21 NO
Remedy
Disconnection or defective contact in wiring harness between battery (+) terminal – M27 (1), (2) Replace – M2 (1) – fuse (20) – K51 (1) – starting switch terminal B (including fusible link) Defective starting switch (between terminal B – BR)
Replace
Disconnection or defective contact in wiring harness between starting switch terminal BR – K51 Replace (3) – D51 (2), (1) – battery relay terminal BR (including diode) Defective contact in wiring harness between battery relay terminal E - revolving frame ground terminal
Repair or replace
Defective battery relay
Replace
PC78MR-6
TROUBLESHOOTING
E-7
E-7 d) Electrical circuit diagram of each system
PC78MR-6
20-521
E-8
TROUBLESHOOTING
E-8 Engine does not stop Cause
Remedy
1 NO
When engine stop solenoid linkage is adjusted, does engine stop?
YES
Defective adjustment of linkage
Adjust
2 • Max. 1 V • Turn starting switch OFF
Is voltage between engine stop solenoid terminal HOLD and chassis ground normal?
YES
NO
Contact of (+) wiring harness with Replace or wiring harness between starting switch terminal ACC – fuse (15) – repair M3 (3) – solenoid terminal HOLD Defective engine stop solenoid
Replace
E-8 Electrical circuit diagram of each system
20-522
PC78MR-6
TROUBLESHOOTING FOR CONTROLLER PUMP CONTROL SYSTEM (C MODE)
Precautions for troubleshooting for controller (pump control system) ........................................................ 20-602 Action taken by controller when trouble occurs and problems on machine ................................................ 20-604 Judgement table for controller (pump control system) and hydraulic equipment........................................ 20-608 Electric circuit diagram of C mode system (For STD spec.) ....................................................................... 20-610 Electric circuit diagram of C mode system (For EU spec.)....................................................................... 20-611-1 C- 1 [E232], C-2 [E233] Trouble in TVC-EPC solenoid system.............................................................. 20-612 C- 3 [E203], C-4 [E213] Trouble in swing holding brake solenoid system.............................................. 20-613 C- 5 [E206], C-6 [E216] Trouble in 2nd travel speed selection solenoid system.................................... 20-614 C- 7 [E411] Trouble in boom swing angle sensor correction ................................................................... 20-615 C- 8 [E251] Trouble in boom bottom pressure sensor (overload sensor) system (For EU spec.) ........ 20-615-1 C- 9 [E258] Short circuit in 5V system of sensor power supply (For EU spec.).................................... 20-615-1 C- 9 [E258] Short circuit in 5V system of sensor power supply (For STD spec.) .................................... 20-616 C-10 [E412], C-11 [E413] Trouble in boom swing angle sensor system .................................................. 20-617 C-12 [E451] Short circuit in boom swing LEFT stop EPC solenoid system is displayed .......................... 20-618 C-13 [E452] Disconnection in boom swing LEFT stop EPC solenoid system is displayed ...................... 20-619 C-14 [E453] Short circuit in boom swing RIGHT stop EPC solenoid system is displayed........................ 20-620 C-15 [E454] Disconnection in boom swing RIGHT stop EPC solenoid system is displayed .................... 20-621 C-16 Boom swing LEFT end cushion does not work at all or normally ..................................................... 20-622 C-17 Boom swing RIGHT end cushion does not work at all or normally ................................................... 20-624 C-18 Work equipment still moves after work equipment lock lever is set to LOCK ................................... 20-626 C-19 Machine does not swing ................................................................................................................... 20-627 C-20 Travel speed does not rise................................................................................................................ 20-628 C-21 Trouble in controller power supply (LED of controller is turned OFF)............................................... 20-628
PC78MR-6
20-601 (1)
TROUBLESHOOTING
PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (PUMP CONTROL SYSTEM)
PRECAUTIONS FOR TROUBLESHOOTING FOR CONTROLLER (PUMP CONTROL SYSTEM) 1. Precautions to be taken when trouble is repaired by itself 1) When a trouble is repaired by itself or 2) When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the service code is not displayed or the monitor displays normally, the same trouble will occur again probably. Accordingly, follow up the condition of the machine sufficiently. 3) After finishing troubleshooting, be sure to delete the saved service code. 2. Handling of function of saving service code When displaying a saved service code for troubleshooting, "take the notes of the all displayed items and delete those items", then reproduce the trouble and start the troubleshooting according to the service code displayed at this time. (Troubles caused by wrong operation, disconnection of a connector, etc. May be saved in the memory. In this case, you can avoid unnecessary work by performing the above operation.)
20-602
PC78MR-6
TROUBLESHOOTING
ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE
ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE User Code
Service Code
Troubled System
Contents of Trouble
1. Short circuit in wiring harness between M97 pin 16 – M20 pin 1 2. Short circuit in EPC solenoid 3. (Wrong operation of switch)
E232
Short circuit in TVC-EPC solenoid system (When emergency pump drive switch is turned ON)
E233
1. Disconnection in wiring harness between M97 pin 16 – M20 pin 1 Disconnection in TVC-EPC solenoid system 2. Disconnection in EPC solenoid 3. Disconnection in wiring harness between M20 pin 2 – M97 pin 23
E203
Short circuit in swing holding brake solenoid system
1. Short circuit in wiring harness between M97 pin 7 – M14 pin 2 2. Short circuit in solenoid
E213
Disconnection in swing holding brake solenoid system (When emergency swing holding brake reset switch is turned ON)
1. Disconnection in wiring harness between M97 pin 7 – M14 pin 2 2. Disconnection in solenoid 3. Disconnection in wiring harness between M14 pin 1 – M97 pin 3 4. (Wrong operation of switch)
E206
Short circuit in 2nd travel speed selection solenoid system
1. Short circuit in wiring harness between M97 pin 27 – M15 pin 2 2. Short circuit in solenoid
Disconnection in 2nd travel speed selection solenoid system
1. Disconnection in wiring harness between M97 pin 27 – M15 pin 2 2. Disconnection in solenoid 3. Disconnection in wiring harness between M15 pin 1 – M97 pin 3
E227
Trouble in engine speed sensor
1. Disconnection in wiring harness between M96 pin 40 – M16 pin 1 2. Disconnection in sensor 3. Disconnection in wiring harness between M16 pin 2 – M96 pin 39
—
E414
Trouble in boom swing angle sensor correction
1. Input voltage is abnormal when angle sensor is corrected (Out of range) When voltage error is out of ± 0.5 V Voltage must be 0.3 – 4.7 V, however
—
E258
Short circuit in 5 V system of sensor power supply
1. Short circuit in wiring harness between M95 pin 22 – M29 pin C, M71 pin C, M72 pin A
E02
E03
— E216
—
20-604
PC78MR-6
TROUBLESHOOTING
Normal Condition
ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE
Action Taken by Controller When Trouble Occurs
Between M97 pin 16 – chassis ground: Min. 1 Mz Between M20 pin 1 – solenoid body: Min. 1 Mz Resistance of M20 EPC solenoid (With When trouble is detected, TVC-EPC switch directed down): 3 – 15 z solenoid output is stopped. Resistance between M97 pin 16 – M20 pin 1: Max. 1 Mz Resistance of M20 EPC solenoid: 3 – 15 z Resistance between M20 pin 2 – M97 pin 23: Max. 1 z
Problems on Machine
Current does not flow in TVC-EPC solenoid. Accordingly, if load is large, engine speed may lower to stall.
Between M97 pin 7 – chassis ground: Min. 1 Mz Between M14 pin 2 – solenoid body: Min. 1 Mz When trouble is detected, swing Resistance of M14 solenoid: 35 – 80 z Since motor brake is not released, holding brake reset solenoid output is machine does not swing. Resistance between M97 pin 7 – M14 pin 2: stopped. Max. 1 z Resistance of M14 solenoid: 35 – 80 z Resistance between M14 pin 1 – M97 pin 3 (With switch directed down): Max. 1 z Between M97 pin 27 – chassis ground: Min. 1 Mz Between M15 pin 2 – solenoid body: Min. 1 Mz When trouble is detected, 2nd travel Resistance of M15 solenoid: 35 – 80 z speed selection solenoid output is Resistance between M97 pin 27 – M15 pin stopped. 2: Max. 1 Mz Resistance of M15 solenoid: 35 – 80 z Resistance between M15 pin 1 – M97 pin 3: Max. 1 z
When speed selector switch pedal is operated, travel speed does not change. (It is kept at 1st gear.)
Resistance between M96 pin 40 – M16 pin 1: Max. 1 z Resistance of M16 sensor: 500 – 1,000 z Resistance between M16 pin 2 – M96 pin 39: Max. 1 z
When trouble is detected, constant current flows in TVC-EPC solenoid (600 mA). Working mode cannot be changed. Engine governor control is limited to operation of fuel control dial.
Since constant current (600 mA) is output to TVC-EPC solenoid, work equipment speed and travel speed are low. If engine speed is low, engine may stall.
Boom swing angle sensor voltage for monitoring At RIGHT swing end: 0.9 V At LEFT swing end: 4.3 V
When potentiometer is corrected, "---" is displayed and initial values are selected. If machine is operated without normal correction, it is controlled with initial values.
Offset end cushion does not work. Stop position for interference prevention is wrong. Displayed depth is wrong.
Resistance between M95 pin 22, M29 pin C, Boom RAISE, arm IN, and offset M71 pin C, M72 pin A - chassis ground: Min. LEFT EPC outputs are stopped. 1 Mz
PC78MR-6
Boom RAISE, arm IN, and offset LEFT operations cannot be executed. (They can be executed if emergency work equipment operation switch is turned ON, however.)
20-605
ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE
TROUBLESHOOTING
User Code Service Code
—
Troubled System
Contents of Trouble
(*1) E251
Trouble in boom bottom pressure sensor (overload sensor) system
1. Disconnection in wiring harness between M95 pin 22 – M92 pin B 2. Short circuit or disconnection in wiring harness between M95 pin 2 – M92 pin C 3. Disconnection in wiring harness between M95 pin 21 – M92 pin A
E412
Disconnection on GND side of boom swing angle sensor
1. Disconnection in wiring harness between M95 pin 21 – M101 pin A
E413
1. Disconnection in wiring harness between M95 pin 22 – M101 pin A 2. Short circuit in wiring harness between M95 Disconnection on power supply side of boom pin 8 – M101 pin B swing angle sensor/Short circuit or 3. Disconnection in wiring harness between disconnection of signal line M95 pin 8 – M101 pin B 4. Defective M101 angle sensor (Internal short circuit)
E451
Short circuit in boom swing LEFT EPC solenoid system
1. Short circuit in wiring harness between M97 pin 5 – M11 pin 2 2. Short circuit in EPC solenoid
E452
Disconnection in boom swing LEFT EPC solenoid system
1. Disconnection in wiring harness between M97 pin 5 – M11 pin 2 2. Disconnection in EPC solenoid 3. Disconnection in wiring harness between M11 pin 1 – M97 pin 23
E453
Short circuit in boom swing RIGHT EPC solenoid system
1. Short circuit in wiring harness between M97 pin 15 – M12 pin 2 2. Short circuit in EPC solenoid
Disconnection in boom swing RIGHT EPC solenoid system
1. Disconnection in wiring harness between M97 pin 15 – M12 pin 2 2. Disconnection in EPC solenoid 3. Disconnection in wiring harness between M12 pin 1 – M97 pin 23
E40
E41
E454
*1. For EU spec. machine only.
20-606 (1)
PC78MR-6
TROUBLESHOOTING
Normal Condition
ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE
Action Taken by Controller When Trouble Occurs
Resistance between M95 pin 22 – M92 pin B: Max. 1 z Resistance between M95 pin 22, M92 pin B – chassis ground: Min. 1 Mz Overload alarm is turned ON. Resistance between M95 pin 2 – M92 pin C: • Buzzer sounds. Max. 1 z • Caution lamp flashes. Resistance between M95 pin 2, M92 pin C – chassis ground: Min. 1 Mz Resistance between M95 pin 21 – M92 pin A: Max. 1z
Problems on Machine
Overload alarm is turned ON. • Buzzer sounds. • Caution lamp flashes.
Resistance between M95 pin 21 – M101 pin C: Max. 1 z Resistance between M95 pin 21 – M29 pin C: Max. 1 z Resistance between M95 pin 20, M101 pin B – chassis ground: Min. 1 M z Resistance between M95 pin 20 – M101 pin B: Max. 1 z Resistance between M72 angle sensor pin A – pin C: 3 – 7 k z Resistance between M72 angle sensor pin A, C – pin B (Which changes as shaft is turned): 0–7kz Resistance between M97 pin 5, M11 pin 2 – chassis ground: Min. 1 M z Resistance of M11 EPC solenoid: 5 – 25 z Resistance between M97 pin 5 – M11 pin 2: Boom swing LEFT EPC solenoid out- Boom cannot be swing to LEFT. put is stopped. Max. 1 z Resistance of M11 EPC solenoid: 3 – 15 z Resistance between M11 pin 1 – M97 pin 23: Max. 1 z Resistance between M97 pin 15, M12 pin 2 – chassis ground: Min. 1 M z Resistance of M12 EPC solenoid: 5 – 25 z Resistance between M97 pin 15 – M12 pin 2: Boom swing RIGHT EPC solenoid output is stopped. Max. 1 z Resistance of M11 EPC solenoid: 3 – 15 z Resistance between M12 pin 1 – M97 pin 23: Max. 1 z
PC78MR-6
Boom cannot be swing RIGHT.
20-607 (1)
JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT
TROUBLESHOOTING
JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT
Service Code
—
—
—
Disconnection on power supply side boom swing angle sensor / short circuit or dsconnection of signal line
Short circuit in 5 V system of sensor power supply
—
Disconnection on GND side of boom swing angle sensor
(*2) Trouble in boom bottom pressure sensor (overload sensor) system
—
Defective correction of boom swing angle sensor
E03
Disconnection in 2nd travel speed selection solenoid system
Short circuit in 2nd travel speed selection solenoid system
Disconnection in swing holding brake solenoid system
Short circuit in swing holding brake solenoid system
Disconnection in TVC-EPC solenoid system
E02
Trouble in engine speed sensor system
User Code
Failure Mode
Short circuit in TVC-EPC solenoid system
Self-diagnosis Display By Controller
Trouble in controller power supply system
Part Which May Cause Trouble
E40
232 233 203 213 206 216 227 414 251 258 412 413
q q q
Boom cannot be swing to LEFT and RIGHT. Speed or power of 2 or more systems of work equipWork equip- ment, travel, swing, and blade is low. ment, travel, swing, blade Engine speed lowers extremely or engine stalls.
q q
q
q q
q
2 or more systems of work equipment, travel, swing, and blade do not move. Boom Speed or power is low.
Arm Boom swing
Work equipment
Boom Does not move.
Arm Boom swing
Travel
q q
Travel speed or power is low.
q q
Travel speed does not change. Swing speed or power is low.
Swing
q q q q
Machine does not swing. Hydraulic drift is large.
Electronic cushion (*2) Overload warning
q q
Boom swing end cushion does not work well or at all. Boom swing RIGHT end cushion does not work at all.
q
Alarm does not stop sounding. Alarm does not start sounding.
After work equipment lock lever is set to LOCK, work equipment still moves Diagnosis code displayed when service code is displayed
E-1 C-1 C-2 C-3 C-4 C-5 C-6 E-6 C-7 C-8 C-9 C-10 C-11
Diagnosis code displayed when trouble is detected by monitoring
—
—
—
—
—
—
—
—
—
—
—
—
—
*2. For EU spec. machine only.
20-608 (1)
PC78MR-6
JUDGEMENT TABLE FOR CONTROLLER (PUMP CONTROL SYSTEM) AND HYDRAULIC EQUIPMENT
TROUBLESHOOTING
Items Checked By Monitoring
Diagnosis code displayed when trouble is not detected by monitoring
Boom swing RIGHT EPC current output
Boom swing LEFT EPC current output
TVC-EPC current output
(*2) Overload warning cancel signal input (2) (*2) Boom bottom pressure
Offset boom sensor voltage input
Engine speed input
ATT selection
Model selection and selection cod
2nd travel speed selection (4)
PPC main pressure (2)
Travel speed selector pedal switch input (4)
Deceleration switch signal input (1)
Air compressor signal input (3)
Swing (4)
Travel (3)
Boom LOWER (5)
E41
Swing holding brake (1)
State of Solenoid
Hydraulic Switch
Boom RAISE (6)
Disconnection in boom swing RIGHT EPC solenoid system
Short circuit in boom swing RIGHT EPC solenoid system
Disconnection in boom swing LEFT EPC solenoid system
Short circuit in boom swing LEFT EPC solenoid system
Self-diagnosis Display By Controller
Monitoring Code
451 452 453 454
1023
1021
1026
1060
1020
1010 1031 1026 1040 1050 1052 1053
(*1)
(*1)
(*1)
(*1) (*1) C-7 – C-14
(*1)
(*1)
(*1)
H-1
(*1)
(*1)
(*1)
H-2
(*1)
(*1)
(*1) (*1)
(*1)
H-3 H-7
(*1)
(*1)
q q q q
H-8 (*1)
H-10 H-11
(*1)
q q q q
H-12 (*1)
(*1)
H-14 H-26
(*1)
(*1)
C-19, H-28 H-33
(*1)
(*1)
C-18, H-34
(*1)
(*1)
H-39
q q
(*1)
q q
(*1)
C-15 (*1)
C-16
(*1) (*1)
—
(*1) (*1)
— C-17
C-12 C-13 C-14 C-15 — —
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
—
F-3 F-4 F-2 F-1 F-7 F-5 F-6
—
—
—
—
—
—
—
—
—
—
—
—
q : Items corresponding to service codes *1. Items that can only be cheked by monitoring *2. For EU spec. machine only.
PC78MR-6
20-609 (1)
TROUBLESHOOTING
ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM
ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM (FOR STD SPEC.)
20-610 (1)
PC78MR-6
TROUBLESHOOTING
PC78MR-6
ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM
20-611
TROUBLESHOOTING
ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM
ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM (FOR EU SPEC.)
20-611-1 (1)
PC78MR-6
TROUBLESHOOTING
PC78MR-6
ELECTRIC CIRCUIT DIAGRAM OF C MODE SYSTEM
20-611-2 (1)
C-1, C-2
TROUBLESHOOTING
2
C-1 [E232], C-2 [E233] Trouble in TVC-EPC solenoid system
a Since this error is displayed when the emergency pump drive switch is turned ON (RAISE), check that this switch is turned OFF (LOWER). Cause
Remedy
1 • Disconnect M20 • 3 – 15 z • Resistance between solenoid and chassis ground: Min. 1 Mz
Is resistance of EPC solenoid normal and is EPC solenoid insulated from chassis?
NO
Defective TVC-EPC solenoid (Internal short circuit, disconnection)
Replace
Disconnection or defective contact in wiring harness between M97 (Female) (16), (23) – M20 (Female) (1), (2)
Repair or replace
Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (16) – M20 (Female) (1)
Repair or replace
Defective controller
Replace
YES
2 • Disconnect M97 • Resistance: 3 – 15 z
NO
Is resistance between M97 (Female) (16) – (23) normal?
YES
3 • Disconnect M97 • Resistance: Min. 1 Mz
Is resistance between M97 (Female) (16) – chassis ground normal?
YES
NO
C-1, C-2 Electrical circuit diagram of each system
20-612
PC78MR-6
C-3, C-4
TROUBLESHOOTING
C-3 [E203], C-4 [E213] Trouble in swing holding brake solenoid system a Since this error is displayed when the emergency swing holding brake release switch is turned ON (RAISE), check that this switch is turned OFF (LOWER). Cause
Remedy
1 • Disconnect M14 • 35 – 80 z • Resistance between solenoid and chassis ground: Min. 1 Mz
NO
Is resistance of solenoid normal and is solenoid insulated from chassis?
Defective swing holding brake solenoid (Internal short circuit, disconnection)
Replace
Disconnection or defective contact in wiring harness between M97 (Female) (7), (3) – M14 (Female) (2), (1)
Repair or replace
Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (7) – M14 (Female) (2)
Repair or replace
Defective controller
Replace
YES
2 • Disconnect M97 • Resistance: 35 – 80z
NO
Is resistance between M97 (Female) (7) – (3) normal?
YES
3 • Disconnect M97 • Resistance: Min. 1 Mz
Is resistance between M97 (Female) (7) – chassis ground normal?
YES
NO
C-3, C-4 Electrical circuit diagram of each system
PC78MR-6
20-613
C-5, C-6
TROUBLESHOOTING
C-5 [E206], C-6 [E216] Trouble in 2nd travel speed selection solenoid system Cause
Remedy
1 • Disconnect M14 • 35 – 80 z • Resistance between solenoid – chassis ground: Min. 1 Mz
NO
Is resistance of solenoid normal and is solenoid insulated from chassis?
Defective 2nd travel speed selection solenoid (Internal short circuit, disconnection)
Replace
Disconnection or defective contact in wiring harness between M97 (Female) (27), (3) – M15 (Female) (2), (1)
Repair or replace
Short circuit with chassis ground or negative (-) wire in wiring harness between M97 (Female) (27) – M15 (Female) (2)
Repair or replace
Defective controller
Replace
YES
2 • Disconnect M97 • Resistance: 35 – 80 z
NO
Is resistance between M97 (Female) (27) – (3) normal?
YES
3 • Disconnect M97 • Resistance: Min. 1 Mz
Is resistance between M97 (Female) (27) – chassis ground normal?
YES
NO
C-5, C-6 Electrical circuit diagram of each system
20-614
PC78MR-6
C-7
TROUBLESHOOTING
C-7 [E411] Trouble in boom swing angle sensor correction a Check by monitoring that model selection code, and ATT selection code are normal. a Check that the angle sensor are installed normally. Cause
Remedy
1 • Reset data again according to potentiometer correction procedure in back mode
NO
Is error turned off after data are reset again
Defective correction (Wrong resetting)
—
Defective controller
Replace
Defective angle sensor having abnormal resistance
Replace
Disconnection or defective contact in wiring harness of circuit having abnormal resistance (Between M95 – M101) (See circuit diagram)
Repair or replace
YES
2 NO
Is monitored voltage of angle sensor at each cylinder end normal?
• See Table 1
YES
3 M101 • Between (A) – (C): 3 – 7 kz • Between (A), (C) – (B): 0 – 7 kz (Resistance changes as shaft is turned)
Is resistance of each angle sensor normal?
YES
Table 1
NO
Voltage (V) Position
Boom swing LEFT end Boom swing RIGHT end
Monitoring Code
Standard Arm
Long Arm
0.9 – 1.8
0.8 – 1.8
3.2 – 4.2
3.2 – 4.2
1033
C-7 Electrical circuit diagram of each system
PC78MR-6
20-615
C-8, C-9
TROUBLESHOOTING
C-8 [E251] Trouble in boom bottom pressure sensor (overload sensor) system (For EU spec.) C-9 [E258] Short circuit in 5V system of sensor power supply (For EU spec.) a Check that fuse 10 is not broken. Cause
Remedy
Disconnection in wiring harness between M97 (20) – fuse box (10) or defective switch
Repair or replace
Defective controller
Replace
Disconnection or short circuit in wiring harness between M95 (2) – M92 (C), M95 (21) – M92 (A), or M95 (22) – M92 (B)
Repair or replace
Defective pressure sensor
Replace
1 When normal: There is a bit. When reset: There is not a bit. (Monitoring code 1026 (2))
NO
Is signal input of overload alarm reset switch normal?
YES
2 • 0 – 26.5 MPa (If boom circuit is relieved at RAISE end, pressure changes.) (Monitoring code 1040)
NO
Is boom cylinder bottom pressure sensor signal normal?
YES
3
• Disconnect M95 and M92.
Is resistance between M95 (2) and M92 (C), between M95 (21) and M92 (A), and between M95 (22) and M92 (B) below 1 z? Is resistance between M95 (2), (22), M92 (C), (B) and chassis ground above 1 Mz?
NO
YES
C-8, C-9 Electrical circuit diagram of each system
20-615-1 (1)
PC78MR-6
C-9
TROUBLESHOOTING
C-9 [E258] Short circuit in 5V system of sensor power supply (For STD spec.) a If E258 is displayed, E40 is also displayed. Carry out the following troubleshooting and the troubleshooting for E40 system (C-10 – C-11). Cause
Remedy
1 • Disconnect M95 • Min. 1Mz
Is resistance between M95 (Female) (22) – (21) chassis ground normal?
NO
Short circuit with chassis ground in wiring harness between M95 (Female) (22) – M101 (Female) (C) (Short circuit of sensor power supply with chassis ground.)
Repair or Replace
Short circuit with chassis ground or negative (-) wire in wiring harness between M101 (Female) (A), M72 (Female) (C)
Repair or Replace
Defective angle sensor having abnormal resistance (Internal short circuit)
Replace
Defective controller
Replace
YES
2 • disconnect M95, M101 and M29. • Min. 1Mz
NO
Is resistance between M95 (Female) (22) – (21)normal?
YES
3 • Between (A) – (C): 3 – 7 kz • Between (A), (C) – (B): 0 – 7 kz (Resistance changes as shaft is turned)
Is resistance of each angle sensor normal?
NO
YES
C-9 Electrical circuit diagram of each system
20-616 (1)
PC78MR-6
C-10, C-11
TROUBLESHOOTING
C-10 [E412], C-11 [E413] Trouble in boom swing angle sensor system Cause
Remedy
1 • 0.3 – 4.7 V (Monitoring code 1033)
NO
Is monitored voltage of boom angle sensor normal?
YES
Defective controller
Replace
Defective boom angle sensor (Disconnection, short circuit with chassis ground)
Replace
• Disconnection or defective contact in wiring harness between M95 (Female) (B), (3) – M101 (Female) (C), (B) • Short circuit with chassis ground or negative (-) wire in wiring harness between M95 (Female) (8) – M101 (Female) (B)
Repair or replace
2 • Between (A) – (C): 3 – 7 kz • Between (A), (C) – (B): 0 – 7 kz (Resistance changes as shaft is turned.)
Is resistance of M101 angle sensor normal?
YES
NO
If the wiring harness between M95(3) – M101 (B) is shorted actually, the controller output is cut out. Accordingly, if [E402] is displayed, the controller is defective.
C-10, C-11 Electrical circuit diagram of each system
PC78MR-6
20-617 (1)
C-12
TROUBLESHOOTING
C-12 [E451] Short circuit in boom swing LEFT stop EPC solenoid system is displayed Cause
Remedy
1 Is resistance between M11 (male) (1) and (2) and between (2) and chassis ground as shown in Table 1?
• Turn starting switch OFF. • Disconnect M11.
NO
Defective boom swing LEFT stop EPC solenoid (Internal disconnection)
Replace
Disconnection in wiring harness between D33 (female) (1) – M11 (female) (2), M97 (female) (23) – M11 (female) (1)
Repair or Replace
Grounding fault or internal short circuit in wiring harness between D33 (female) (2) – M97 (female) (5)
Repair or Replace
Defective controller
Replace
YES
2 Is resistance between D33 (female) (1) and chassis ground and between D33 (female) (1) and M97 (female) (23) as shown in Table 2?
• Turn starting switch OFF. • Disconnect D33 and M97.
NO
YES
3 Is resistance between M97 (female) (5) and M97 (female) (23) between M97 (female) (5) as shown table 3?
• Turn starting switch OFF. • Disconnect D33 and M97.
NO
YES
Table 1
Table 2
Between M11 (male) (1) – (2)
5 – 25 z
Between D33 (1) – chassis ground
Between M11 (male) (2) – chassis ground
Min. 1 z
Between D33 (1) – M97 (23)
Table 3 Min. 1 Mz 5 – 25 z
Between M97 (5) – chassis ground
Min. 1 Mz
Between M97 (5) – M97 (23)
Min. 1 Mz
C-12 Electrical circuit diagram of each system
20-618 (1)
PC78MR-6
C-13
TROUBLESHOOTING
C-13 [E452] Disconnection in boom swing LEFT stop EPC solenoid system is displayed Cause
Remedy
1 • Turn starting switch OFF. • Disconnect M11. • Resistance: 5 – 25z
NO
Is resistance between M11 (male) (1) and (2) normal?
Defective boom swing LEFT stop EPC solenoid (Internal disconnection)
Replace
Disconnection in wiring harness between D33 (female) (1) – M11 (female) (2), D15 (female) (2) – M97 (female) (5), or M97 (female) (23) – M11 (female) (1)
Repair or Replace
Defective diode (Disconnection)
Replace
Defective controller
Replace
YES
2 Is resistance between D33 (female) (1) and M97 (female) (23) and between D33 (female) (2) and M97 (female) (5) as shown in Table 1?
• Turn starting switch OFF. • Disconnect D33 and M97.
NO
YES
3 • Turn starting switch OFF. • Disconnect D33. * See TESTING AND ADJUSTING.
Is diode D15 normal?
NO
YES
Table 1 Between D33 (1) – M97 (23)
5 – 25 z
Between D33 (2) – M97 (26)
Min. 1 z
C-13 Electrical circuit diagram of each system
PC78MR-6
20-619 (1)
C-14
TROUBLESHOOTING
C-14 [E453] Short circuit in boom swing RIGHT stop EPC solenoid system is displayed Cause
Remedy
1 Is resistance between M12 (male) (1) and (2) and between (2) and chassis ground as shown in Table 1?
• Turn starting switch OFF. • Disconnect M12.
NO
Defective boom swing RIGHT stop EPC solenoid (Internal short circuit or grounding fault)
Replace
Grounding fault or internal short circuit in wiring harness between D31 (female) (1) – M12 (2) or between M97 (23) – M12 (1)
Repair or Replace
Grounding fault or internal short circuit in wiring harness between D31 (female) (2) – M97 (female) (15)
Repair or Replace
Defective controller
Replace
YES
2 Is resistance between D31 (female) (1) and chassis ground and between D31 (female) (1) and M97 (female) (23) as shown in Table 2?
• Turn starting switch OFF. • Disconnect D31 and M97.
NO
YES
3 Is resistance between M97 (female) (15) and chassis ground and between M97 (female) (15) and M97 (female) (23) as shown in Table 3?
• Turn starting switch OFF. • Disconnect D31 and M97.
NO
YES
Table 1
Table 2
Between M12 (male) (1) – (2)
5 – 25 z
Between D31 (1) – chassis ground
Between M12 (male) (2) – chassis ground
Min. 1 z
Between D31 (1) – M97 (23)
Table 3 Min. 1 Mz 5 – 25 z
Between M97 (15) – chassis ground
Min. 1 Mz
Between M97 (15) – M97 (23)
Min. 1 Mz
C-14 Electrical circuit diagram of each system
20-620 (1)
PC78MR-6
C-15
TROUBLESHOOTING
C-15 [E454] Disconnection in boom swing RIGHT stop EPC solenoid system is displayed Cause
Remedy
1 • Turn starting switch OFF. • Disconnect M12. • Resistance: 5 – 25z
NO
Is resistance between M12 (male) (1) and (2) normal?
Defective boom swing RIGHT stop EPC solenoid (Internal disconnection)
Replace
Disconnection in wiring harness between D31 (female) (1) – M12 (2), D31 (female) (2) – M97 (15), or M97 (23) – M12 (1))
Repair or Replace
Defective diode (Disconnection)
Replace
Defective controller
Replace
YES
2 Is resistance between D31 (female) (1) and M97 (female) (23) and between D31 (female) (2) and M97 (female) (15) as shown in Table 1?
• Turn starting switch OFF. • Disconnect D31 and M97.
NO
YES
3 • Turn starting switch OFF. • Disconnect D31. * See TESTING AND ADJUSTING.
Is diode D31 normal?
NO
YES
Table 1 Between D31 (1) – M97 (23)
5 – 25 z
Between D31 (2) – M97 (15)
Min. 1 z
C-15 Electrical circuit diagram of each system
PC78MR-6
20-621 (1)
C-16
TROUBLESHOOTING
C-16 Boom swing LEFT end cushion does not work at all or normally a a a a
Check that the boom swing angle sensor voltage input is normal by monitoring code 1033. (Standard value: 0.9 V when boom swing is at left end) Check that the boom swing EPC current output is normal by monitoring code 1052.) Check installation of the boom swing angle sensor for abnormality. Cause
Remedy
1 When boom swing angle sensor is corrected again, does condition become normal?
NO
YES Defective correction
—
Defective boom swing angle sensor
Replace
Disconnection or defective contact in wiring harness of circuit having abnormal resistance (See circuit diagram)
Repair or replace
2 • Between (A) and (C): 3 – 7 kz • Between (A), (C) and (B): 0 – 7 kz (If shaft is rotated, resistance changes.)
NO
Is resistance of boom swing angle sensor normal?
YES
3 • Normal value: Max. 1 z
Is resistance between M101 (A) and M95 (21), between M101 (B) and M95 (8), and between M101 (C) and M95 (22) normal?
NO
YES Defective controller
20-622 (1)
PC78MR-6
TROUBLESHOOTING
C-16
C-16 Electrical circuit diagram of each system
PC78MR-6
20-623 (1)
C-17
TROUBLESHOOTING
C-17 Boom swing RIGHT end cushion does not work at all or normally a Check that the boom swing angle sensor voltage input is normal by monitoring code 1033. (Standard value:At 4.3 V) a Check that the boom swing RIGHT EPC current output is normal by monitoring code 1053. a Check installation of the boom swing angle sensor for abnormality. Cause
Remedy
1 When boom swing angle sensor is corrected again, does condition become normal?
NO
YES Defective correction
—
Defective boom swing angle sensor
Replace
Disconnection or defective contact in wiring harness of circuit having abnormal resistance
Repair or replace
Defective controller
Replace
2 • Between (A) and (C): 3 – 7 kz • Between (A), (C) and (B): 0 – 7 kz (If shaft is rotated, resistance changes.)
NO
Is resistance of boom swing angle sensor normal?
YES
3 • Normal value: Max. 1 z
Is resistance between M101 (A) and M95 (21), between M101 (B) and M95 (8), and between M101 (C) and M95 (22) normal?
NO
YES
20-624 (1)
PC78MR-6
TROUBLESHOOTING
C-17
C-17 Electrical circuit diagram of each system
PC78MR-6
20-625 (1)
C-18
TROUBLESHOOTING
C-18 Work equipment still moves after work equipment lock lever is set to LOCK Cause
Remedy
1 • When pushed, (1) – (3) are connected to each other. • When released, (1) – (2) are connected to each other (Test on switch unit)
NO
Is PPC hydraulic lock switch normal?
Defective hydraulic lock switch
Replace
Short circuit with positive (+) wire in wiring harness between K28 (2) – M13 (2)
Repair or replace wiring harness
Defective PPC lock solenoid valve
Replace
YES
2 • When locked: 0 V • When released: 20 – 29 V
Is voltage between M13 (2) – chassis ground normal?
NO
YES
C-18 Electrical circuit diagram of each system
20-626 (1)
PC78MR-6
C-19
TROUBLESHOOTING
C-19 Machine does not swing a Carry out the following troubleshooting when [E-203] and [E-213] are not displayed. Cause
Remedy
1 • Check swing control lever.
Is bit pattern 1023 – (4) displayed?
NO Go to F-1
—
Go to H-34
—
YES
C-19 Electrical circuit diagram of each system
PC78MR-6
20-627 (1)
C-20, C-21
TROUBLESHOOTING
C-20 Travel speed does not rise a Carry out the following troubleshooting when [E-206] and [E-216] are not displayed. Cause
Remedy
1 • 20 – 29 V • Turn starting switch ON • Disconnect K3
NO
Is voltage between K3 (Female) (2) – chassis ground normal?
YES
2 • • • •
In 1-spool mode: Max. 1Mz In 2-spool mode: Max. 1Mz Turn starting switch OFF Disconnect K3
NO
Is resistance between K3 (Male) (2) – (1) normal?
Defective 2nd travel speed selection switch
Replace
Disconnection or defective contact in wiring harness between K3 (Female) (1) – chassis ground
Repair or replace
Defective controller
Replace
Disconnection or defective contact in wiring harness between M95 (Female) (5) – K3 (Female) (2)
Repair or replace
YES
3 • 20 – 29 V • Turn starting switch ON • Disconnect K3
Is voltage between M95 (5) – chassis ground normal?
YES
NO
C-20 Electrical circuit diagram of each system
C-21 Trouble in controller power supply (LED of controller is turned OFF) a See E-1.
20-628 (1)
PC78MR-6
TROUBLESHOOTING FOR CONTROLLER (INPUT SIGNAL SYSTEM) (F MODE)
F-1 F-2 F-3 F-4 F-5 F-6 F-7
Bit pattern 1023-(4) Bit pattern 1023-(3) Bit pattern 1023-(6) Bit pattern 1023-(5) Bit pattern 1026-(1) Bit pattern 1026-(4) Bit pattern 1021-(3)
Swing pressure switch does not light up........................................................... 20-702 Travel pressure switch does not light up........................................................... 20-703 Boom RAISE pressure switch does not light up ............................................... 20-704 Arm IN pressure switch does not light up ......................................................... 20-705 Deceleration switch of left knob does not light up............................................. 20-706 2nd travel speed selection switch (pedal) does not light up.............................. 20-707 Compressor signal does not light up................................................................. 20-708
a When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the monitoring code is displayed normally, the condition has returned to normal. a Before carrying out troubleshooting, check that all the related connectors are properly inserted. a Always connect any disconnected connectors before going on to the next step.
PC78MR-6
20-701
F-1
TROUBLESHOOTING
2
F-1 Bit pattern 1023-(4) Swing pressure switch does not light up Before operating the swing control lever (even a little distance), stick the bucket into the ground to lock the swing mechanism. Cause • Disconnect M22. • Start engine. • Set swing control lever in neutral: Min. 1Mz • Move swing control lever to swing to left: Max. 1z • See note.
Is resistance between M22 (Male) (1) – (2) normal and are they insulated from chassis ground?
• Disconnect M23. • Start engine. • Set swing control lever in neutral: Min. 1 Mz • Move swing control lever to swing to right: Max. 1 z • See note.
Is resistance between M23 (Male) (1) – (2) normal and are they insulated from chassis ground?
• Turn starting switch OFF. • Disconnect M95, M22, and M23. • Between M95 – M22, M23: Max. 1z • Between wiring harness – chassis ground: Min. 1 z
Is resistance between M95 (Female) (24) – M22, M23 (Female) (2) normal and are they insulated from chassis ground?
• Start engine. • Set swing control lever in neutral: 20 – 30 V • Move swing control lever: Max. 1V
1 NO
Defective left swing pressure switch
Replace
NO
Defective right swing pressure switch
Replace
Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (24) – M22 (Female) (2), M23 (Female) (2)
Repair or replace
Disconnection or defective contact in wiring harness between M22 (Female) (1), M23 (Female) (1) – chassis ground
Repair or replace
Defective controller
Replace
YES
2
YES
3 NO
YES
4 Is voltage between M95 (24) – chassis ground normal?
YES
Note:
Remedy
NO
This item may be judged by fitting a short connector. In this case, judge by the voltage between M95 (24) – chassis ground. • If 20 – 30 V: Go to YES. • If below 1 V: Go to NO.
F-1 Electrical circuit diagram of each system
20-702
PC78MR-6
F-2
TROUBLESHOOTING
2
F-2 Bit pattern 1023-(3) Travel pressure switch does not light up Before operating the travel lever (even a little distance), check the condition and safety around the machine. Before operating the travel lever, put a block in the grouser of the track shoe or between the sprocket and frame to lock the track shoe. Cause • Disconnect M25. • Start engine. • Set swing control lever in neutral: Min. 1 Mz • Move travel lever: Max. 1 z • See note.
Remedy
1 Is resistance between M25 (Male) (1) – (2) normal and are they insulated from chassis ground?
NO
Defective travel pressure switch
Replace
Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (18) – M25 (Female) (2)
Repair or replace
Disconnection or defective contact in wiring harness between M25 (Female) (1) – chassis ground
Repair or replace
Defective controller
Replace
YES
2 • • • •
Turn starting switch OFF. Disconnect M95 and M25. Between M95 – M25: Max. 1 z Between wiring harness – chassis ground: Min. 1 Mz
Is resistance between M95 (Female) (18) – M25 (Female) (2) normal and are they insulated from chassis ground?
NO
YES
3 • • • •
Start engine. Set travel lever in neutral: 20 – 30 V Move travel lever: Max. 1 V
Is voltage between M95 (18) – chassis ground normal?
YES
Note:
NO
This item may be judged by fitting a short connector. In this case, judge by the voltage between M95 (18) – chassis ground. • If 20 – 30 V: Go to YES. • If below 1 V: Go to NO.
F-2 Electrical circuit diagram of each system
PC78MR-6
20-703
F-3
TROUBLESHOOTING
F-3 Bit pattern 1023-(6) Boom RAISE pressure switch does not light up When measuring while the engine is running, move each lever to the degree that the work equipment will not move. Cause • Start engine. • Set boom control lever in neutral: 20 – 30 V • Move boom control lever to lower boom: Max. 1 V
• Disconnect M21. • Start engine. • Set boom control lever in neutral: Min. 1 Mz • Move boom control lever to lower boom: Max. 1 z • See note.
Remedy
1 NO
Is voltage between M95 (12) – chassis ground normal?
YES
Defective governor or pump controller
Replace
Defective boom RAISE pressure switch
Replace
Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (12) – M21 (Female) (2)
Repair or replace
Disconnection or defective contact in wiring harness between M21 (Female) (1) – chassis ground
Repair or replace
2 Is resistance between M21 (Male) (1) – (2) normal and are they insulated from chassis ground?
NO
YES
3 • • • •
Turn starting switch OFF. Disconnect M95 – M21. Between M95 – M21: Max. 1 z Between wiring harness – chassis ground: Min. 1 Mz
Is resistance between M95 (Female) (12) – M21 (Female) (2) normal and are they insulated from chassis ground?
YES
Note:
NO
This item may be judged by fitting a short connector. In this case, judge by the voltage between M95 (12) – chassis ground. • If 20 – 30 V: Go to YES. • If below 1 V: Go to NO.
F-3 Electrical circuit diagram of each system
20-704
PC78MR-6
F-4
TROUBLESHOOTING
F-4 Bit pattern 1023-(5) Arm IN pressure switch does not light up When measuring while the engine is running, move each lever to the degree that the work equipment will not move. Cause • Start engine. • Set arm control lever in neutral: 20 – 30 V • Move arm control lever to move arm in: Max. 1 V
• Disconnect M24. • Start engine. • Set arm control lever in neutral: Min. 1 Mz • Move arm control lever to move arm in: Max. 1 z • See note.
Remedy
1 NO
Is voltage between M95 (6) – chassis ground normal?
YES
Defective governor or pump controller
Replace
Defective arm IN pressure switch
Replace
Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (6) – M24 (Female) (2)
Repair or replace
Disconnection or defective contact in wiring harness between M24 (Female) (1) – chassis ground
Repair or replace
2 Is resistance between M24 (Male) (1) – (2) normal and are they insulated from chassis ground?
NO
YES
3 • Turn starting switch OFF. • Disconnect M95 – M24. • Between M95 and M24: Max. 1z • Between wiring harness – chassis ground: Min. 1 Mz
Is resistance between M95 (Female) (6) – M24 (Female) (2) normal and are they insulated from chassis ground?
YES
Note:
NO
This item may be judged by fitting a short connector. In this case, judge by the voltage between M95 (6) – chassis ground. • If 20 – 30 V: Go to YES. • If below 1 V: Go to NO.
F-4 Electrical circuit diagram of each system
PC78MR-6
20-705
F-5
TROUBLESHOOTING
F-5 Bit pattern 1026-(1) Deceleration switch of left knob does not light up a Check that fuse 1! is normal. Cause
Remedy
1 • Turn starting switch ON. • Turn knob switch ON: 20 – 30 V • Turn knob switch OFF: Max. 1 V
NO
Is voltage between M97 (9) – chassis ground normal?
YES
2 • Turn starting switch ON. • 20 – 30 V
NO
Is voltage between K18 (Male) (2) – chassis ground normal?
Defective governor or pump controller
Replace
Disconnection or defective contact in wiring harness between fuse (11) – K18 (1) – knob switch inlet
Repair or replace
Defective left knob switch
Replace
Disconnection or defective contact in wiring harness between K18 (2) – M97 (Female) (9)
Repair or replace
YES • Turn starting switch OFF. • Disconnect knob switch terminal K18. • Turn knob switch ON: Max. 1z • Turn knob switch OFF: Min. 1 Mz
3 Is resistance between K18 (Male) (1) – (2) normal?
YES
NO
F-5 Electrical circuit diagram of each system
20-706
PC78MR-6
F-6
TROUBLESHOOTING
2
F-6 Bit pattern 1026-(4) 2nd travel speed selection switch (pedal) does not light up Cause • Turn starting switch OFF. • Disconnect 2nd travel speed selection switch terminal K3. • Turn 2nd travel speed selection switch ON: Max. 1z • Turn 2nd travel speed selection switch OFF: Min. 1 Mz • • • •
Turn starting switch OFF. Disconnect M95 and K3. Between M95 – K3: Max. 1z Between wiring harness – chassis ground: Min. 1 Mz
Remedy
1 NO
Is resistance between K3 (Male) (1) – (2) normal?
Defective 2nd travel speed selection switch (pedal)
Replace
Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M95 (Female) (5) – K3 (Female) (2)
Repair or replace
Disconnection or defective contact in wiring harness between K3 (Female) (1) – chassis ground
Repair or replace
Defective controller
Replace
YES
2 Is resistance between K3 (Female) (2) – M95 (Female) (5) normal and are they insulated from chassis ground?
NO
YES
3 • Turn starting switch ON. • Turn 2nd travel speed selection switch ON: Max. 1 V
Is voltage between M95 (Female) (5) – chassis ground normal?
YES
NO
. F-6 Electrical circuit diagram of each system
PC78MR-6
20-707
F-7
TROUBLESHOOTING
2
F-7 Bit pattern 1021-(3) Compressor signal does not light up
a Before starting measurement, check that the compressor operates normally when the air conditioner is turned ON.
• Turn starting switch ON. • Disconnect M97. • When compressor operates (= Just after air conditioner is turned ON): 20 – 30 V • When compressor stops (= After air conditioner is turned off): Max. 1 V
Cause
Remedy
Disconnection, defective contact, or short circuit with chassis ground in wiring harness between M97 (Female) (10) – K11 (Female) (8)
Repair or replace
Defective controller
Replace
1 Is voltage between M97 (Female) (10) – chassis ground normal?
NO
YES
. F-7 Electrical circuit diagram of each system
20-708
PC78MR-6
TROUBLESHOOTING FOR HYDRAULIC AND MECHANICAL SYSTEMS (H MODE) Table of hydraulic failure modes and their causes ...................................................................................... 20-804 H- 1 Speed or power of 2 or more systems of work equipment (boom, arm, bucket), travel, swing, and blade is low ................................................................................................................................. 20-806 a) Speed or power of all work equipment (including blade), travel, and swing systems is low .......... 20-806 b) Speed or power of all work equipment (excluding blade) and travel is low ................................... 20-807 c) Speed or power of swing and blade is low..................................................................................... 20-807 d) Speed or power of travel and blade is low ..................................................................................... 20-808 e) Speed or power of all work equipment (excluding blade) is low .................................................... 20-808 f) Speed or power of travel and swing is low..................................................................................... 20-808 H- 2 Engine speed lowers extremely or engine stalls................................................................................ 20-809 H- 3 2 or more systems of work equipment (boom, arm, bucket), travel, swing, and blade do not move..........20-811 a) All work equipment (including blade), travel, and swing systems do not move ..............................20-811 b) All work equipment (excluding blade) and travel systems do not move ........................................ 20-812 c) Swing and blade systems do not move ......................................................................................... 20-812 d) Travel and blade systems do not move ......................................................................................... 20-813 e) All work equipment (excluding blade) does not move ................................................................... 20-813 H- 4 Abnormal sound comes out (from around pump) .............................................................................. 20-814 H- 5 Fine controllability or response is low ................................................................................................ 20-815 H- 6 Hydraulic drift is large (all work equipment and blade) ...................................................................... 20-816 H- 7 Boom speed or power is low (other work equipment is normal) ........................................................ 20-817 a) Boom RAISE speed or power is low.............................................................................................. 20-817 b) Boom LOWER speed or power is low ........................................................................................... 20-818 H- 8 Arm speed or power is low (other work equipment is normal) ........................................................... 20-819 a) Arm IN speed or power is low........................................................................................................ 20-819 b) Arm OUT speed or power is low.................................................................................................... 20-820 H- 9 Bucket speed or power is low (other work equipment is normal)....................................................... 20-821 a) Bucket CURL speed or power is low ............................................................................................. 20-821 b) Bucket DUMP speed or power is low ............................................................................................ 20-822 H-10 Boom swing speed or power is low (other work equipment is normal) .............................................. 20-823 a) Swing left speed or power is low ................................................................................................... 20-823 b) Swing right speed or power is low ................................................................................................. 20-824 H-11 Boom does not move ......................................................................................................................... 20-825 a) Boom does not rise........................................................................................................................ 20-825 b) Boom does not lower ..................................................................................................................... 20-826 H-12 Arm does not move............................................................................................................................ 20-827 a) Arm does not move in.................................................................................................................... 20-827 b) Arm does not move out.................................................................................................................. 20-828 H-13 Bucket does not move ....................................................................................................................... 20-829 a) Bucket does not curl ...................................................................................................................... 20-829 b) Bucket does not dump ................................................................................................................... 20-830 H-14 Boom swing does not move .............................................................................................................. 20-831 a) Boom swing LEFT does not move................................................................................................. 20-831 b) Boom swing RIGHT does not move .............................................................................................. 20-832 H-15 Hydraulic drift of boom is large .......................................................................................................... 20-833 H-16 Hydraulic drift of arm is large ............................................................................................................. 20-833 H-17 Hydraulic drift of bucket is large......................................................................................................... 20-834
PC78MR-6
20-801
H-18 Hydraulic drift of swing is large ......................................................................................................... 20-834 a) Hydraulic drift of swing to left is large ............................................................................................ 20-834 b) Hydraulic drift of swing to right is large .......................................................................................... 20-834 H-19 Time lage is large (when engine speed is low) .................................................................................. 20-835 H-20 Part loaded more moves slower in compound operation of work equipment .................................... 20-835 H-21 Boom RAISE speed is low in compound operation of swing and boom RAISE ................................ 20-836 H-22 Travel speed lowers extremely in compound operation of travel and boom RAISE .......................... 20-836 H-23 Speed is low in compound operation of work equipment relief and swing, work equipment relief and work equipment ....................................................................................... 20-836 H-24 Travel deviation is large ..................................................................................................................... 20-837 a) Travel deviation is large during ordinary travel .............................................................................. 20-837 b) Travel deviation is large when machine starts (but during normal ordinary travel) ........................ 20-838 H-25 Travel deviation is large in compound operation of travel and swing, travel and work equipment .......................................................................................................................................... 20-839 H-26 Travel speed or power is low (work equipment, swing, and blade operations are normal)................ 20-840 H-27 Machine cannot be steered sharply or steering force is insufficient................................................... 20-842 H-28 Travel speed does not change at all or does not change quickly ...................................................... 20-843 H-29 Machine does not travel..................................................................................................................... 20-844 H-29 Supplement........................................................................................................................................ 20-845 H-30 Overrun of travel is large.................................................................................................................... 20-846 H-31 Travel hydraulic drift is large .............................................................................................................. 20-846 H-32 Fine controllability or response is low ................................................................................................ 20-847 H-33 Swing speed or power is low (work equipment, travel, and blade operations are normal) ................ 20-848 H-34 Machine does not swing (work equipment, travel, and blade operations are normal) ....................... 20-850 a) Swing speed or power is low in both directions ............................................................................. 20-850 b) Swing speed or power is low in either direction ............................................................................. 20-851 H-35 Swing acceleration is low................................................................................................................... 20-852 a) Swing acceleration is low in both directions................................................................................... 20-852 b) Swing acceleration is low in either direction .................................................................................. 20-852 H-36 Overrun of swing is large ................................................................................................................... 20-853 a) Overrun of swing is large in both directions ................................................................................... 20-853 b) Overrun of swing is large in either direction................................................................................... 20-853 H-37 Large shock is made when machine stops swinging ......................................................................... 20-854 H-38 Large abnormal sound is made when machine stops swinging......................................................... 20-854 H-39 Swing hydraulic drift is large .............................................................................................................. 20-855 H-40 Fine controllability more response of swing is low ............................................................................. 20-856 H-41 Blade speed or power is low (work equipment, travel, and swing operations are normal) ................ 20-857 H-42 Blade does not move (work equipment, travel, and swing operations are normal) ........................... 20-858 a) Blade does not rise ........................................................................................................................ 20-858 b) Blade does not lower ..................................................................................................................... 20-859 H-43 Hydraulic drift of blade is large........................................................................................................... 20-860 H-44 Fine controllability or response of blade is low .................................................................................. 20-861
20-802
PC78MR-6
TABLE OF HYDRAULIC FAILURE MODES AND THEIR CAUSES
TROUBLESHOOTING
TABLE OF HYDRAULIC FAILURE MODES AND THEIR CAUSES
Machine model PC78MR-6
Logic valve
Merge valve
Main relief circuit check valve
Main relief valve
Unload valve
LS bypass choke
Pressure compensation valve
Spool
LS line choke
Control pump
Control Valve
Gear pump
Orifice
Servo valve
EPC valve
LS valve
PC valve
Piston pump
Hydraulic Pump
Strainer
Cap
Hydraulic oil
Failure mode
PTO spline
Tank
Engine system
Part Which May Cause Trouble
q
Standard specification
Failure mode Speed or power of 2 or more systems or work equipment, travel, and blade is low Engine speed lowers extremely or engine stalls All work equip- 2 or more systems of work equipment, travel, swing, and blade do not move ment, travel, swing, blade Abnormal sound comes out (From around pump) Fine controllability or response is low
q q
q q q q q q q
q q
q q
q q
q q
q q
q q q
q q
q q q q
q
q q q q
q q
q q
q
Hydraulic drift is large (All work equipment and blade)
q q
Boom Speed or Arm power of work equipment is Bucket low
Work equipment
q q q q
Boom swing
q q
Boom
q q q q
Work equipArm ment does not move Bucket
q q
Boom swing
q q
Boom
q q
Hydraulic drift Arm of work equipment is large Bucket
q q
Boom swing
q
Time lag is large (When engine speed is low) Part loaded more moves slower in compound operation of work equipment Compound operation
Boom RAISE speed is low in compound operation of swing and boom RAISE
q
Travel speed lowers extremely in compound operation of travel and boom RAISE Speed is low in compound operation of work equipment relief and swing, work equipment relief and other work equipment
q
q
q q
q
q q q
q q
q
q q
q
q
q q q
Machine does not travel
q q
q
Overrun of travel is large
q
Travel deviation is large Travel deviation is large in compound operation of travel and swing, travel and work equipment
q q q
Travel speed or power is low Machine cannot be steered sharply or steering force is insufficient Travel
q
Travel speed does not change at all or does not change quickly
Travel hydraulic drift is large
Swing
Fine controllability or response is low
q q
Swing speed or power is low
q q
Machine does not swing
q q
Swing acceleration is low
q q
q
q q
Overrun or swing is large Large shock is made when machine stops swinging
q
Large abnormal sound is made when machine stops swinging Swing hydraulic drift is large
Blade
20-804
Fine controllability or response of swing is low
q q
Blade speed or power is low
q
Blade does not move
q
Hydraulic drift of blade is large
q
Fine controllability or response of blade is low
q
q
PC78MR-6
q
PC78MR-6 q
q q q
q
q
q
q
q
q
q
q
q
q
q
q q q
q
q
q q
q
q
q
q
q
q q
q q H- 2
q
q
q q
q q q
q q
q
q q q H-11
q H-12
q H-13
q H-14
q q q H-15
q q H-16
q q H-17
q q H-18
q q
q q
q
q q
q
q q
q
q q q q q q
H-35
q q
q
q q q q
H-36
q q
q
q
q
q q
q q q q q
q q q
q
q
q q q
q
q q
q
q q q
q q q
q q
q q
q q q
q H-25
q q q q q q q q
q q q q q q q q
q q q q
q q q
q q q q q q
q
q
q
q
q q
q q q q q
Emergency pump drive switch
PPC pressure switch
Hydraulic cylinder
Final drive
Parking brake valve
Parking brake
2nd speed select valve and piston
Swing Motor
Check valve
Counterbalance valve
Piston motor
Center swivel joint
Swing machinery
Reaction prevention valve
Parking brake
Suction valve
Check valve
Solenoid Valve
Safety valve
Piston motor
Left offset EPC valve
Arm IN EPC valve
Boom RAISE EPC valve
Swing holding brake solenoid valve
PPC Valve
2nd travel speed selection solenoid valve
PPC main pressure lock solenoid
q q q Control relief valve
PPC valve (Offset pedal)
PPC valve (Blade bar)
PPC valve (Travel lever)
Control Valve
PPC valve (Left lever) 1 – 0
PPC valve (Right lever) 1 – 0
2nd travel speed selection choke
Swing PPC line choke
Swing PPC slow return valve
Pressure release valve
Blade safety valve
Gear pump circuit relief valve
Boom assist valve
Boom lock valve
Suction valve
Centralized safety valve
Travel LS bleed valve
Travel junction variable throttle valve
PPC circuit check valve
TROUBLESHOOTING TABLE OF HYDRAULIC FAILURE MODES AND THEIR CAUSES
Travel Motor
q
q
q
q
q
q q
Failure mode
H- 1
H- 3
H- 4
H- 5
q q q H- 6
H- 7
q q q H- 8
q q H- 9
q q H-10
H-19
H-20
H-21
H-22
H-23
H-24
H-26
H-27
H-28
H-29
q q
H-30
H-31
q q
H-32
H-33
H-34
H-37
H-38
H-39
q
q
H-40
H-41
q
q
H-42
q
q
H-43
q
q
H-44
20-805
H-1
TROUBLESHOOTING
H-1 Speed or power of 2 or more systems of work equipment (boom, arm, bucket), travel, swing, and blade is low a Before carrying out troubleshooting, check that the oil level in the tank is proper. a If the engine speed lowers, carry out H-2 first. a If "individual factor" is indicated, a trouble which occurs less frequently than the detected trouble may have occurred or several troubles may be combined. Accordingly, carry out troubleshooting for each of those troubles. a Select a combination of systems which have low speed or power from Table 1 before going to the next troubleshooting. a If the combination of the detected troubles is not in Table 1, carry out troubleshooting for the actuators of each system "which has low speed or power" (H-7 – H-10). Q : Normal x : Speed or power is low
Table 1 Work Equipment
Travel
x
x
x
x
Q
Q
Q
Swing
Blade
Diagnosis Item
x
x
Go to a
Q
Q
Go to b
x
x
Go to c
x
Q
x
Go to d
x
Q
Q
Q
Go to e
Q
x
x
Q
Go to f
a) Speed or power of work equipment (including blade), travel, and swing systems is low Cause
Remedy
1 NO
Is suction strainer clogged?
YES
Clogged suction strainer (Defective suction by pump)
Clean or replace
Go to H-1, b)
—
2 • 3.14 ± 0.3 MPa {32 ± 3 kg/cm2} • Run engine at full throttle
Is output pressure of PPC main pressure lock NO solenoid valve normal?
YES
3 NO
When control relief valve is adjusted, is trouble repaired?
YES
Defective adjustment of control valve Adjust
4 When PPC lock solenoid valve is replaced, is NO trouble repaired?
YES
20-806
Defective pump control
Replace
Defective PPC main pressure lock solenoid
Replace
PC78MR-6
H-1
TROUBLESHOOTING
b) Speed or power of all work equipment (excluding blade) and travel is low Cause
Remedy
1 • Curl bucket • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is work equipment relief pressure normal?
YES
2 • Curl bucket • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
Is travel relief pressure normal?
NO
Go to corresponding section in H-7 – 10, 26
—
NO
Defective main pump (Lowering of volumetric efficiency)
Repair or replace
Defective boom assist valve
Repair or replace
Go to corresponding section in H-7 – 10, 26
—
Defective main relief valve
Repair or replace
Defective unload valve
Repair or replace
Go to diagnosis No. 3
Repair or replace
YES
3 When blade is relieved in RAISE mode, does the travel speed rise?
YES
4 • Curl bucket • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is travel relief pressure normal?
YES
5 NO
When travel relief valve is adjusted or replaced, is trouble repaired?
YES
6 NO
Does unload valve move smoothly?
YES
c) Speed or power of swing and blade is low Cause • Lower blade • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle
Remedy
1 NO
Is gear pump relief pressure normal?
YES
Go to corresponding section in H-26, 33
—
Defective gear pump
Repair or replace
Defective gear pump relief pressure
Adjust or replace
2 When gear pump relief valve is adjusted or NO replaced, is trouble repaired?
YES
PC78MR-6
20-807
H-1
TROUBLESHOOTING
d) Speed or power of travel and blade is low Cause
Remedy
1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is travel relief pressure normal?
YES
Go to corresponding section H-26, 41
—
Go to corresponding section H-26, 41
—
Go to corresponding section H-26, 41
—
Defective swivel joint
Repair or replace
2 • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle
NO
Is blade LOWER relief pressure normal?
YES
3 When hose is disconnected from valve outlet NO and plugged, is relief pressure normal?
YES
e) Speed or power of all work equipment (excluding blade) is low Cause
Remedy
1 Is all PPC pressure normal (At PPC pressure NO inlet of control valve?
YES • 2.11 ± 0.1 MPa {21.5 ± 1 kg/cm2} • Run engine at full throttle and curl bucket
2 NO
Is LS differential pressure normal?
Defective adjustment of pump Adjust LS valve
YES
3 When compound operation of travel, work NO equipment, and swing is performed, is trouble repaired?
YES
Go to corresponding section in H-7 –10
—
Defective travel pressure compensation valve
4 NO
Is PPC pressure normal at only 1 place (When single operation is performed)?
YES
Defective check valve in PPC circuit having normal PPC Replace pressure
5 Is check valve at swing holding brake pressure inlet of logic valve normal?
YES
f)
NO
Leakage of PPC pressure caused by defective ball check valve Go to corresponding section in H-7 – 10
—
Speed or power of travel and swing is low Carry out the troubleshooting in b) above.
a If the PPC main pressure is judged low by troubleshooting in b) above, this trouble can occur.
20-808
PC78MR-6
H-2
TROUBLESHOOTING
H-2 Engine speed lowers extremely or engine stalls Cause
Remedy
1 When bucket is relieved in CURL mode and blade is relieved in RAISE mode, does engine speed lower much?
NO
YES
2 When blade is relieved in RAISE mode or swing is relieved and work NO equipment is operated without relieving simultaneously, does engine speed lower much?
YES
Execute diagnosis No. 4
3 • 26.5 ± 1.45 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
Is bucket CURL relief pressure normal?
NO
YES
4 • 12.74 ± 1.47 MPa {130 ± 15 kg/cm2} • Run engine at full throttle
Is blade RAISE relief pressure normal?
NO
YES
5 NO
When gear pump circuit relief valve is adjusted, repaired, or replaced, is trouble repaired?
YES
Defective gear pump circuit relief valve
Adjust or replace
Defective main relief valve
Repair or replace
Defective connection
Repair
Defective TVC-EPC valve (Defective solenoid)
Replace
Defective controller
Repair or replace
6 NO
When main relief valve is replaced, is trouble repaired?
YES
7 Does monitor display error code "E02" NO of TVC trouble?
YES
8 NO
Is TVC connector connected?
YES
9 When engine speed changes, does TVC current change?
NO
YES To next page
PC78MR-6
20-809
H-2
TROUBLESHOOTING
Cause
Remedy
From previous page
10 • 0.54 ~ 0.83 MPa {5.5 ~ 8.5 kg/cm2} • Run engine at full throttle
Is output voltage of TVC-EPC solenoid NO normal?
YES
11 When PC valve is adjusted, is trouble repaired?
NO
YES
Defective PC valve
Adjust or replace
12 NO
When orifice of servo is cleaned, is trouble repaired?
YES
Clogged orifice
13 When EPC valve of TVC is replaced, is NO trouble repaired?
YES
Execute diagnosis No. 11
—
Defective EPC valve
Repair or replace
Defective engine system
—
Defective pump or servo
Repair or replace
14 When pump assembly is replaced, is trouble repaired?
YES
20-810
NO
PC78MR-6
H-3
TROUBLESHOOTING
H-3 2 or more systems of work equipment (boom, arm, bucket), travel, swing, and blade do not move a Before carrying out troubleshooting, check that the oil level in the tank is proper. a Select a combination of systems which do not move from Table 1 before going to the next troubleshooting. a If the combination of the detected troubles is not in Table 1, carry out troubleshooting for the actuators of each system "which does not move" (H-10 – 13). Q : Normal x : Speed or power is low
Table 1 Work Equipment
Travel
x
x
x
x
Q
Q
Q
Swing
Blade
Diagnosis Item
x
x
Go to a
Q
Q
Go to b
x
x
Go to c
x
Q
x
Go to d
x
Q
Q
Q
Go to e
Q
x
x
Q
Go to f
a) All work equipment (including blade), travel, and swing systems do not move Cause
Remedy
1 When engine is cranked, does oil flow NO out of pump?
YES
2 When oil does not flow out of any of following pumps • Main pump • Gear pump • Control pump
YES
3 NO
Is suction strainer clogged?
YES
Clogged suction strainer
Clean or adjust
Defective main pump shaft
Replace
Defective damper or spline
Replace
Defective gear pump
Replace
Defective coupling or spline
Replace
4 NO
Is damper or spline damaged?
YES
5 NO
When oil flows out of main pump but does not flow out of gear pump and control pump.
YES
6 Is coupling or spline between main pump and gear pump damaged?
YES
NO
To item No. 5 on next page
PC78MR-6
20-811
H-3
TROUBLESHOOTING
Cause
Remedy
From item 3 on previous page
5 NO
When engine is cranked, does oil flow out of control pump?
Defective control pump
Repair or replace
YES
6 • 3.14 ± 0.3 MPa {32 ± 3 kg/cm2} • Run engine at full throttle
Is output pressure of PPC main pressure lock NO solenoid valve normal?
YES
Defective PPC main pressure Repair or lock solenoid valve or replace defective electric system Go to corresponding section in H-11 ~ 14, 29, 34, 42
—
b) All work equipment (excluding blade) and travel systems do not move Cause
Remedy
1 NO
When engine is cranked, does oil flow out of control?
Defective control
Repair or replace
YES
2 • 3.14 ± 0.3 MPa {32 ± 3 kg/cm2} • Run engine at full throttle
Is output pressure of PPC main pressure lock NO solenoid valve normal?
Defective PPC main pressure Repair or lock solenoid valve or replace defective electric system
YES
3 NO
Is only 1 part of each of work equipment and travel normal?
YES
Go to corresponding section in H-11 – 14, 29
Repair or replace
Defective check valve in PPC Repair or circuit having normal replace pressure
c) Swing and blade systems do not move Cause
Remedy
1 NO
When engine is cranked, does oil flow out of pump?
Defective control pump
Repair or replace
Go to corresponding section in H-34, 42
—
Defective gear pump circuit relief valve
Adjust or replace
YES
2 When gear pump circuit relief valve is adjusted or replaced, is trouble repaired?
YES
20-812
NO
PC78MR-6
H-3
TROUBLESHOOTING
d) Travel and blade systems do not move Cause
Remedy
1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is travel relief pressure normal?
YES
Go to corresponding section H-29
—
Go to corresponding section H-42
—
Go to corresponding section H-29, 42
—
Defective swivel joint
Repair or replace
2 • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle
NO
Is blade relief pressure normal?
YES
3 When hose is disconnected from valve outlet NO and plugged, is relief pressure normal?
YES
e) All work equipment (excluding blade) does not move Cause
Remedy
1 • 3.14 ± 0.5 MPa {32 ± 5 kg/cm2} • Run engine at full throttle
NO
Are all PPC pressures normal (At connected PPC pressure inlets)?
YES
Go to corresponding section in H-11 – 14
—
Go to corresponding section in H-11 – 14
—
2 NO
Is only 1 place normal?
YES
Defective check valve in PPC circuit having normal Replace pressure
Note: If machine is equipped with an attachment, check that attachment.
PC78MR-6
20-813
H-4
TROUBLESHOOTING
H-4 Abnormal sound comes out (from around pump) Cause
Remedy
1 NO
Is oil level in hydraulic tank normal?
Low hydraulic oil level
Supply hydraulic oil
Low hydraulic oil level
—
YES
2 NO
Are there bubbles in hydraulic tank?
YES
3 NO
When engine is stopped, do bubbles in tank disappear?
YES
Go to diagnosis No. 4
4 Foreign matter: Cloth, etc.
Is suction strainer clogged with foreign matter?
NO
YES
Foreign matter (Cloth, etc.) clogging suction strainer
Remove
Defective inside pump
Repair or replace
5 Is suction strainer clotted with metallic foreign NO matter or metal chips?
YES
6 Is hydraulic tank cap clogged?
YES
20-814
NO
Re-inspect Operate machine and (according to observe condition for a while change of condition) Negative pressure caused by Clean or clogging of cap replace cap
PC78MR-6
H-5
TROUBLESHOOTING
H-5 Fine controllability or response is low (Two or more systems have low fine controllability or response simultaneously) a The following troubleshooting is not applicable to travel, swing, and blade systems. Cause
Remedy
1 • See TESTING AND ADJUSTING
NO
Is LS differential pressure normal?
YES
2 NO
Is LS line choke clogged?
YES
Clogging of LS line choke
Clean or replace
Clogging of orifice of unload valve
Clean
Defective PC valve or servo piston
Repair or replace
Clogging of orifice or piston pump
Clean
Defective LS valve
Repair or replace
Defective adjustment of LS valve
Adjust
3 NO
Is orifice of unload valve clogged?
YES
4 NO
Is orifice of piston pump clogged?
YES
5 When LS valve is adjusted, is trouble repaired?
YES
PC78MR-6
NO
20-815
H-6
TROUBLESHOOTING
H-6 Hydraulic drift is large (all work equipment and blade) a Before carrying out troubleshooting, check that oil level in the tank is proper. Cause
Remedy
1 NO
Is pressure release plug of control valve tightened?
Leakage through pressure release circuit
Retighten
Leakage through pressure release circuit
—
YES
2 NO
Is seal of pressure release plug broken?
YES
3 When centralized safety valve is replaced, is trouble repaired?
YES
20-816
NO
Go to corresponding section in H-15 – H-18 Defective concentrated safety valve
Clean
PC78MR-6
H-7
TROUBLESHOOTING
H-7 Boom speed or power is low (other work equipment is normal) a) Boom RAISE speed or power is low a When the boom speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause
Remedy
1
• Run engine at full throttle and set boom in neutral: 410 mA • Run engine at full throttle and raise boom: 100 mA
When boom is raised in monitoring mode 1050, does current lower?
• 0.54 ~ 0.83 MPa {5.5 ± 8.5 kg/cm2} • Run engine at full throttle
Is output pressure of pump TVC-EPC solenoid normal?
NO
Diagnose by F-3
YES
2 NO
Defective pump TVCEPC solenoid
Replace
NO
Defective operation of control valve spool
Repair or replace
NO
Defective operation of pressure compensation valve
NO
Defective centralized safety valve
Replace
Defective suction valve (Boom LOWER side)
Repair or replace
Defective boom cylinder packing
Repair or replace
Defective seat of check valve of boom assist valve
Repair or replace
Go to diagnosis No. 3
—
Defective boom RAISE PPC valve
Repair or replace
YES
3 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is boom relief pressure normal?
YES
4 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle
Is PPC valve output pressure normal? (PPC pressure inlet of control valve)
YES
5 Does control valve spool move smoothly?
YES
6 Does pressure compensation valve move smoothly?
YES
7 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
Is boom LOWER relief pressure normal?
YES
8 NO
When pilot hose of boom assist valve is disconnected, does speed rise?
YES
9 (Move boom RAISE with arm IN oil.)
When PPC hose is replaced with arm IN hose NO on control valve side, is trouble repaired?
YES
PC78MR-6
20-817
H-7
TROUBLESHOOTING
b) Boom LOWER speed or power is low a When the boom speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. Cause
Remedy
1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is boom LOWER relief pressure normal?
YES
2 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle
NO
Is PPC valve output pressure normal? (At control valve PPC pressure inlet)
YES
3 NO
Does control valve spool move smoothly?
Defective operation of control valve spool
Repair or replace
Malfunction of lock valve
Repair, clean, or replace
Malfunction of spool
Check 3 again
Defective concentrated safety valve
Replace
Defective suction valve (Boom LOWER side)
Repair or replace
Go to diagnosis No. 3
—
Defective boom LOWER PPC valve
Repair or replace
YES
4 Does poppet of pilot piston of boom lock valve move smoothly and its orifice free from clogging?
NO
YES
5 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is boom RAISE relief pressure normal?
YES
6 (Move boom LOWER with arm OUT oil.)
When PPC hose of control valve is replaced NO with arm DUMP, is trouble repaired? (Return it immediately after testing.)
YES
20-818
PC78MR-6
H-8
TROUBLESHOOTING
H-8 Arm speed or power is low (Other work equipment is normal) a) Arm IN speed or power is low a When the arm speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause • Run engine at full throttle and set arm in neutral: 410 mA • Run engine at full throttle and raise boom: 100 mA
Remedy
1 NO
When arm is moved IN in monitoring mode 1050, does current lower?
Diagnose by F-3
YES
2 • 0.54 – 0.83 MPa {5.5 – 8.5 kg/cm2} • Run engine at full throttle.
NO
Is output pressure of pump TVC-EPC solenoid normal?
Defective pump TVC-EPC solenoid
Replace
Defective arm IN PPC valve
Repair or replace
YES
3 • 26.5 ± 1.49 MPa {270 ± 15 kg/cm2} • Run engine at full throttle.
NO
Is arm IN relief pressure normal?
YES
4 • 3.14± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle.
NO
Is EPC valve output pressure normal? (PPC pressure inlet of control valve)
YES
5 Does control valve spool move smoothly?
NO
Defective operation of control Repair or valve spool replace
YES
6 Does pressure compensation valve move NO smoothly?
Defective operation of pressure compensation valve
YES
7 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle.
NO
Is arm OUT relief pressure normal?
YES
Defective centralized safety valve
Replace
Defective suction valve (Boom Repair or LOWER side) replace
8 • (Move arm IN with boom RAISE)
When PPC hose is replaced with boom RAISE hose on control valve side, is trouble repaired? (Return it immediately after testing.)
NO
YES
Defective arm IN PPC valve
Repair or replace
Go to diagnosis No. 3
—
Defective seats of swing brake circuit check valve and swing PPC slow-return valve
Repair or replace
9 When swing operation and arm IN NO operation are executed simultaneously, is trouble repaired?
YES
PC78MR-6
20-819
H-8
TROUBLESHOOTING
b) Arm OUT speed or power is low a When the arm speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause
Remedy
1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is arm OUT relief pressure normal?
YES
2 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle
NO
Is PPC valve output pressure normal? (At control valve PPC pressure inlet)
YES
3 NO
Malfunction of control valve spool
Repair or replace
Does pressure compensation valve move NO smoothly?
Malfunction of pressure compensation valve
Repair or replace
YES
Defective arm cylinder packing
Repair or replace
Defective concentrated safety valve
Replace
Defective suction valve (Arm IN side)
Repair or replace
Go to diagnosis No. 3
—
Defective arm OUT PPC valve
Repair or replace
Does control valve spool move smoothly?
YES
4
5 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is arm OUT relief pressure normal?
YES
6 • (Move arm OUT with boom LOWER oil)
When PPC hose of control valve is replaced with boom LOWER, is trouble repaired? (Return it immediately after testing.)
YES
20-820
NO
PC78MR-6
H-9
TROUBLESHOOTING
H-9 Bucket speed or power is low (Other work equipment is normal) a) Bucket CURL speed or power is low a When the bucket speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause
Remedy
1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is bucket CURL relief pressure normal?
YES
2 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle
NO
Is PPC valve output pressure normal? (At control valve PPC pressure inlet)
YES
3 NO
Malfunction of control valve spool
Repair or replace
Does pressure compensation valve move NO smoothly?
Malfunction of pressure compensation valve
Repair or replace
YES
Defective arm cylinder packing
Repair or replace
Defective concentrated safety valve
Replace
Defective suction valve (Bucket CURL side)
Repair or replace
Go to diagnosis No. 3
—
Does control valve spool move smoothly?
YES
4
5 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is bucket DUMP relief pressure normal?
YES
6 • (Move bucket CURL with arm IN oil)
When PPC hose of control valve is NO replaced with arm IN, is trouble repaired? (Return it immediately after testing.)
YES
PC78MR-6
Defective bucket CURL PPC Repair or valve replace
20-821
H-9
TROUBLESHOOTING
b) Bucket DUMP speed or power is low a When the bucket speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause
Remedy
1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is bucket DUMP relief pressure normal?
YES
2 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle
NO
Is PPC valve output pressure normal? (At control valve PPC pressure inlet)
YES
3 Does control valve spool move smoothly?
NO
Malfunction of control valve spool
Repair or replace
Malfunction of pressure compensation valve
Repair or replace
Defective bucket cylinder packing
Repair or replace
Defective concentrated safety valve
Replace
Defective suction valve (Bucket DUMP side)
Repair or replace
Go to diagnosis No. 3
—
YES
4 Does pressure compensation valve move NO smoothly?
YES
5 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is bucket CURL relief pressure normal?
YES
6 • (Move bucket DUMP with arm OUT oil)
When PPC hose of control valve is replaced NO with arm OUT, is trouble repaired? (Return it immediately after testing.)
YES
20-822
Defective bucket DUMP PPC Repair or valve replace
PC78MR-6
H-10
TROUBLESHOOTING
H-10 Boom swing speed or power is low (other work equipment is normal) a) Swing left speed or power is low a Relieve the swing LEFT actuator in a position at which the swing end cushion system does not detect the work equipment. a When the offset speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause
Remedy
1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is swing left relief pressure normal?
YES
2 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle
Is solenoid valve output pressure normal? NO (PPC pressure inlet of control valve)
YES
3 NO
Defective operation of control Repair or valve spool replace
Does pressure compensation valve move NO smoothly?
Defective operation of Repair or pressure compensation valve replace
Does control valve spool move smoothly?
YES
4
YES
Defective swing cylinder packing
Repair or replace
Defective pressure compensation valve
Repair or replace
Defective packing seal near extraction end of swing cylinder
Repair or replace
Go to troubleshooting No. 3
—
Defective swing left PPC valve
Repair or replace
Defective swing left solenoid valve
Repair or replace
5 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is swing right relief pressure normal?
YES
6 (Move swing left by curling bucket)
When PPC hose and bucket CURL hose are exchanged at control valve, does condition become normal? (Return hoses immediately after testing.)
NO
YES
7 Is PPC valve output pressure normal?
PC78MR-6
NO
20-823
H-10
TROUBLESHOOTING
b) Swing right speed or power is low a Relieve the swing RIGHT actuator in a position at which the swing end cushion system does not detect the work equipment. a When the offset speed is low, if the result of troubleshooting No. 1 is "NO", take actions against the relief pressure and carry out troubleshooting No. 2. a Check that the emergency pump drive switch is turned OFF. Cause
Remedy
1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is swing right relief pressure normal?
YES
2 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle
NO
Is PPC valve output pressure normal? (PPC pressure inlet of control valve)
YES
3 NO
Defective operation of control Repair or valve spool replace
Does pressure compensation valve move NO smoothly?
Defective operation of Repair or pressure compensation valve replace
Does control valve spool move smoothly?
YES
4
YES
Defective swing cylinder packing
Repair or replace
Defective pressure compensation valve
Repair or replace
Defective suction valve (Right swing side)
Repair or replace
Go to troubleshooting No. 3
—
5 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is swing right relief pressure normal?
YES
6 (Move swing right by dumping bucket)
When PPC hose and bucket DUMP hose NO are exchanged at control valve, does condition become normal? (Return hoses immediately after testing.)
YES
20-824
Defective swing right PPC valve
Repair or replace
PC78MR-6
H-11
TROUBLESHOOTING
H-11 Boom does not move a Carry out the following troubleshooting, if the boom does not move when operated singly (when the other work equipment is normal). a) Boom does not rise Cause
Remedy
1 kg/cm2}
• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle.
NO
Is PPC valve output pressure normal? (At control valve PPC pressure inlet)
YES
2 NO
Does boom lower?
Malfunction of control valve spool
Repair or replace
Deformation of cylinder or work equipment (Boom does not rise above the deformed part
Repair or replace
YES
3 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle.
NO
When boom is raised, is pump relief pressure normal?
YES
4 NO
Does spool move smoothly?
YES
Malfunction of spool in raising Repair or mode replace Malfunction of pressure compensation valve
Repair or replace
Go to diagnosis No. 2
—
Defective boom RAISE PPC valve
Repair or replace
5 (Move boom lower with arm IN oil)
When PPC hose of control valve is replaced with arm IN, is trouble repaired? (Return it immediately after testing.)
YES
PC78MR-6
NO
20-825
H-11
TROUBLESHOOTING
b) Boom does not lower Cause
Remedy
1 • 2.94 ± 0.49 MPa {30 ± 5 kg/cm2} • Run engine at full throttle.
Is PPC valve output pressure normal? NO (At control valve PPC pressure inlet)
YES
2 NO
Does boom rise?
Malfunction of control valve Repair or spool or seizure of lock valve replace poppet
YES
3 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle.
When boom is lowered, is pump relief NO pressure normal?
YES
4 NO
Does spool move smoothly?
YES
Malfunction of spool in lowering mode
Repair or replace
Malfunction of pressure compensation valve
Repair or replace
Go to diagnosis No. 2
—
5 (Move boom lower with arm OUT oil)
When PPC hose of control valve is replaced with arm OUT, is trouble repaired? (Return it immediately after testing.)
NO
YES
Defective boom LOWER PPC Repair or valve replace
6 Is seal drain line of control valve clogged?
YES
20-826
NO
Defective lock valve
Repair or replace
Defective lock valve caused by clogging
Repair or replace
PC78MR-6
H-12
TROUBLESHOOTING
H-12 Arm does not move a Carry out the following troubleshooting, if the arm does not move when operated singly (when the other work equipment is normal). a) Arm does not move in Cause
Remedy
1 kg/cm2}
• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle
NO
Is PPC valve output pressure normal? (At control valve PPC pressure inlet.)
YES
2 NO
Does arm move out?
Malfunction of control valve spool
Repair or replace
Deformation of cylinder or work equipment (Arm does not move more than deformed part)
Repair or replace
Malfunction of spool in IN mode
Repair or replace
Malfunction of pressure compensation valve
Repair or replace
Defective arm IN PPC valve
Repair or replace
Go to diagnosis No. 2
—
YES
3 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
When arm is moved in, is pump relief pressure normal?
YES
4 NO
Does spool move smoothly?
YES
5 (Move arm out with boom RAISE oil)
When PPC hose of control valve is replaced with boom RAISE, is trouble repaired? (Return it immediately after testing.)
NO
YES
6 When swing operation and arm IN NO operation are executed simultaneously, is trouble repaired?
YES
PC78MR-6
Defective seats of swing Repair or brake circuit check valve and replace swing PPC slow-return valve
20-827
H-12
TROUBLESHOOTING
b) Arm does not move out Cause
Remedy
1 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle
NO
Is PPC valve output pressure normal? (At control valve PPC pressure inlet)
YES
2 NO
Does arm move in?
Malfunction of control valve spool
Repair or replace
Deformation of cylinder or work equipment (Arm does not move more than deformed part)
Repair or replace
Malfunction of spool in OUT mode
Repair or replace
Malfunction of pressure compensation valve
Repair or replace
Defective arm OUT PPC valve
Repair or replace
Go to diagnosis No. 2
—
YES
3 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
When arm is moved out, is pump relief pressure normal?
YES
4 NO
Does spool move smoothly?
YES
5 (Move arm out with boom LOWER oil.)
When PPC hose of control valve is replaced with boom LOWER, is trouble NO repaired? (Return it immediately after testing.)
YES
20-828
PC78MR-6
H-13
TROUBLESHOOTING
H-13 Bucket does not move a Carry out the following troubleshooting, if the bucket does not move when operated singly (when the other work equipment is normal). a) Bucket does not curl Cause
Remedy
1 kg/cm2}
• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle
NO
Is PPC valve output pressure normal? (At control valve PPC pressure inlet.)
YES
2 NO
Is bucket dumped?
Malfunction of control valve spool
Repair or replace
Deformation of cylinder or work equipment (Bucket does not move more than deformed part)
Repair or replace
YES
3 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
When bucket is curled, is pump relief pressure normal?
YES
4 NO
Does spool move smoothly?
YES
Malfunction of spool in CURL Repair or mode replace Malfunction of pressure compensation valve
Repair or replace
Go to diagnosis No. 2
—
Defective bucket CURL PPC valve
Repair or replace
5 (Move bucket curl with arm IN oil)
When PPC hose of control valve is replaced with arm IN, is trouble repaired? (Return it immediately after testing.)
YES
PC78MR-6
NO
20-829
H-13
TROUBLESHOOTING
b) Bucket does not dump Cause
Remedy
1 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle
NO
Is PPC valve output pressure normal? (At control valve PPC pressure inlet)
YES
2 NO
Is bucket curled?
Malfunction of control valve spool
Repair or replace
YES
3 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
When bucket is dumped, is pump relief NO pressure normal?
YES
4 NO
Does spool move smoothly?
YES
Deformation of cylinder or work equipment Repair or (Bucket does not move more replace than deformed part) Malfunction of spool in DUMP Repair or mode replace Malfunction of pressure compensation valve
Repair or replace
Go to diagnosis No. 2
—
5 (Move bucket dump with arm OUT)
When PPC hose of control valve is replaced with arm OUT, is trouble repaired? (Return it immediately after testing.)
YES
20-830
NO
Defective bucket DUMP PPC Repair or valve replace
PC78MR-6
H-14
TROUBLESHOOTING
H-14 Boom swing does not move a Carry out the following troubleshooting when the offset boom does not move when it is operated singly (and the other work equipment is normal). a) Boom swing LEFT does not move Cause
Remedy
1 kg/cm2}
• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle.
Is solenoid valve output pressure normal? NO (PPC pressure inlet of control valve)
YES
2 NO
Does boom swing right move?
Defective operation of control Repair or valve spool replace
YES
3 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle.
NO
When swing left is operated, is pump relief pressure normal?
YES
Deformed cylinder or work equipment (Work equipment does not move over deformed part)
Repair or replace
Defective operation of spool
Repair or replace
4 NO
Does spool move smoothly?
YES
Defective operation of Repair or pressure compensation valve replace
5 (Move swing left by curling bucket)
When PPC hose and bucket CURL hose are exchanged at control valve, does condition become normal? (Return hoses immediately after testing.)
NO
Go to troubleshooting No. 2
—
Defective swing left PPC valve
Repair or replace
Defective swing left EPC valve
Repair or replace
YES
6 Is PPC valve output pressure normal?
YES
PC78MR-6
NO
20-831
H-14
TROUBLESHOOTING
b) Boom swing RIGHT does not move Cause
Remedy
1 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle.
NO
Is PPC valve output pressure normal? (PPC pressure inlet of control valve)
YES
2 NO
Does boom swing left move?
Defective operation of control Repair or valve spool replace
YES • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle.
3 NO
When swing right is operated, is pump relief pressure normal?
YES
4 NO
Does spool move smoothly?
YES
Deformed cylinder or work equipment (Work equipment does not move over deformed part)
Repair or replace
Defective operation of spool
Repair or replace
Defective operation of Repair or pressure compensation valve replace
5 (Move swing right by dumping bucket)
When PPC hose and bucket DUMP hose NO are exchanged at control valve, does condition become normal? (Return hoses immediately after testing.)
Go to troubleshooting No. 2
—
Defective swing RIGHT PPC valve
Repair or replace
Defective swing RIGHT EPC valve
Repair or replace
YES
6 Is PPC valve output pressure normal?
YES
20-832
NO
PC78MR-6
H-15, H-16
TROUBLESHOOTING
H-15 Hydraulic drift of boom is large Cause
Remedy
1 NO
Is leakage from hydraulic cylinder normal?
Defective cylinder piston packing
Repair or replace
Defective boom lock valve
Repair or replace
Defective boom lock valve
Replace
YES
2 NO
When centralized safety valve is replaced, is trouble repaired?
YES
H-16 Hydraulic drift of arm is large Cause
Remedy
1 NO
Is leakage from hydraulic cylinder normal?
Defective cylinder piston packing
Repair or replace
Defective centralized safety valve
Replace
Defective oil-tightness of control valve spool
Repair or replace
Defective centralized safety valve
Repair or replace
YES
2 NO
When centralized safety valve is replaced, is trouble repaired?
YES
3 When suction valve is replaced with blind plug, is trouble repaired?
YES
PC78MR-6
NO
20-833
H-17, H-18
TROUBLESHOOTING
H-17 Hydraulic drift of bucket is large Cause
Remedy
1 NO
Is leakage from hydraulic cylinder normal?
Defective cylinder piston packing
Repair or replace
Defective centralized safety valve
Replace
Defective oil-tightness of control valve spool
Repair or replace
Defective suction valve
Repair or replace
YES
2 NO
When centralized safety valve is replaced, is trouble repaired?
YES
3 NO
When suction valve is replaced with blind plug, is trouble repaired?
YES
H-18 Hydraulic drift of swing is large a) Hydraulic drift of swing to left is large Cause
Remedy
1 NO
Is leakage from hydraulic cylinder normal?
Defective cylinder piston packing
Repair or replace
Defective oil-tightness of control valve spool
Repair or replace
Defective suction valve
Repair or replace
YES
2 NO
When suction valve is replaced with blind plug, does condition become normal?
YES
b) Hydraulic drift of swing to right is large Cause
Remedy
1 Is leakage from hydraulic cylinder normal?
YES
20-834
NO
Defective cylinder piston packing
Repair or replace
Defective oil-tightness of control valve spool
Repair or replace
PC78MR-6
H-19, H-20
TROUBLESHOOTING
H-19 Time lag is large (When engine speed is low) Cause
Remedy
1 NO
Is suction valve normal (Free from seizure)?
Defective suction valve
Replace
Defective back pressure valve
Replace
Defective pump servo piston
Replace pump assembly
Defective LS valve
Replace
YES
2 When poppet and spring of back NO pressure valve are replaced, is trouble repaired?
YES
3 When LS valve is replaced, is trouble NO repaired?
YES
H-20 Part loaded more moves slower in compound operation of work equipment Cause
Remedy
Defective counterbalance valve on Replace lighter load side
Compound Operation
Heavier Load Side
Lighter Load Side
1 Boom RAISE + Arm IN
Boom RAISE
Arm IN
2 Boom RAISE + Arm OUT
Arm OUT
Boom RAISE
3 Boom RAISE + Bucket CURL Boom RAISE
Bucket CURL
4 Arm IN + Bucket DUMP
Arm OUT
Bucket CURL
5 Boom LOWER + Arm OUT
Arm OUT
Boom LOWER
PC78MR-6
20-835
H-21, H-22, H-23
TROUBLESHOOTING
H-21 Boom RAISE speed is low in compound operation of swing and boom RAISE a Carry out the following troubleshooting, if the swing operation and boom RAISE operation are normal when executed singly (Swing LS pressure is not generated) . When this operation is executed, the gear pump assists the boom RAISE circuit. Cause
Remedy
Defective boom assist valve or LS Clean or select valve replace
H-22 Travel speed lowers extremely in compound operation of travel and boom RAISE a Carry out the following troubleshooting, if the work equipment (Boom RAISE) operation and travel operation are normal when executed singly. a Carry out the following troubleshooting, only when the boom RAISE circuit (LS) pressure is higher than the travel circuit (LS) pressure. Cause Malfunction of LS bleed valve (Clogged choke, etc.)
Remedy Repair or replace
H-23 Speed is low in compound operation of work equipment relief and swing, work equipment relief and other work equipment Cause Defective choke of LS bypass
20-836
Remedy Replace
PC78MR-6
H-24
TROUBLESHOOTING
H-24 Travel deviation is large a) Travel deviation is large during ordinary travel
• Check shoe tension difference between both sides • Check rollers for revolution trouble • Check for deformation and damage
• Above 3.14 ± 0.49 MPa {Above 32 ± 5 kg/cm2} • Run engine at full throttle • Move lever to stroke end
Cause
1
Remedy
NO
Is undercarriage troubled?
YES
Defective undercarriage
Repair or replace
Wrong adjustment or breakage of pump
Adjust, repair or replace
Defective travel junction variable choke valve
Clean or replace
Defective pump merge valve
Repair or replace
Malfunction of logic valve
Check, clean, repair or replace
Defective check valve of main relief circuit
Repair or replace
Malfunction of unload valve (Clogging of hole, etc.)
Repair or replace
2 Are PPC output pressures on both NO sides normal?
YES
3 When both hoses are exchanged at pump outlet, does deviating direction change?
NO
YES
4 When both hoses between control NO valve and swivel joint are exchanged, does deviating direction change?
YES
5 When only travel operation is executed
Is pressure at top PP pressure pickup port of control valve same as pump pressure?
NO
YES
6 Does spool of travel junction NO variable choke valve move smoothly and is hole free from clogging?
YES
7 Does spool of pump merge valve move smoothly and is hole free from clogging?
NO
YES
8 When both check valves of main relief circuit are exchanged, does deviating direction change?
NO
YES
9 Does unload valve move smoothly NO and is hole free from clogging?
YES To 12 on next page
PC78MR-6
To 10 on next page
To 13 on next page
20-837
H-24
TROUBLESHOOTING
From 4 on previous page
From 9 on previous page
From 2 on previous page
Cause
Remedy
10 NO
Does pressure compensation valve move smoothly?
Defective pressure compensation valve
Repair or replace
Malfunction of spool
Repair or replace
Go to diagnosis No. 11
—
Defective travel motor (Motor, counterbalance valve, final drive)
Check, repair or replace
Defective swivel joint
Repair or replace
Defective PPC circuit check valve of control valve
Repair or replace
Defective PPC valve
Repair or replace
Abnormal PPC pressure output caused by interference
Adjust
YES
11 Does travel spool move smoothly?
NO
YES
12 When both hoses between swivel joint and travel motor are NO exchanged, does deviating direction change?
YES
13 When both PPC hose are exchanged, does deviating direction change?
NO
YES
14 Does lever interfere with floor?
NO
YES
b) Travel deviation is large when machine starts (but normal during ordinary travel) Cause
1 When machine starts, is dragging sound of brake heard from travel motor on deviating side?
Remedy
NO
YES
Delay of release of parking brake Repair or (Malfunction of brake, brake valve replace
2 Does counterbalance valve of travel motor move smoothly?
YES
20-838
NO
Go to diagnosis No. 5 in (a) above Malfunction of counterbalance valve
Repair or replace
PC78MR-6
H-25
TROUBLESHOOTING
H-25 Travel deviation is large in compound operation of travel and swing, travel and work equipment a Carry out the following troubleshooting, if the travel operation is normal when executed singly. Cause
Remedy
1 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle
Is output pressure of swing holding NO brake solenoid normal?
YES
PC78MR-6
Defective swing holding brake solenoid
Replace
Seizure of filter and check valve at output pressure inlet port of swing holding brake solenoid of rotary valve
Replace
20-839
H-26
TROUBLESHOOTING
H-26 Travel speed or power is low (Work equipment, swing, and blade operations are normal) a If another part of the work equipment has a trouble, see H-1. a Check that the emergency pump drive switch is turned OFF. Cause • Run engine at full throttle and set travel lever in neutral: 410 mA • Drive machine with engine at full throttle: 100 mA • Run engine at full throttle and set travel lever in neutral: 0.45 – 0.83 MPa {5.5 – 8.5 kg/cm2} • Drive machine with engine at full throttle: 0 – 0.2 MPa {0 – 2 kg/cm2}
Remedy
1 When machine is driven in monitoring mode 1050, does current lower?
NO
YES
2 NO
Is output pressure of TVC-EPC solenoid normal?
Defective TVC-EPC solenoid
Replace
Omission of connection
Connect
Disconnection or defective controller
Replace
Malfunction pump merge-divider valve
Repair or replace
Malfunction logic valve
Repair or replace
Large resistance to travel motor and undercarriage
Repair or replace
Large leakage through travel motor or swivel joint
Repair or replace
Malfunction of spool
Repair or replace
YES
3 NO
Is travel pressure switch connected?
YES
4 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is travel relief pressure normal?
YES
5 Is pressure at top PP pressure pickup port of control valve same as port pressure?
NO
YES
6 Does pump merge-divider spool move smoothly and is hole free from clogging?
NO
YES
• When driven on flat concrete with engine at full throttle, if pressure is below 11.7 MPa {120 kg/cm2}
7 NO
Is pump pressure normal during travel?
YES
8 • Above 3.14 ± 0.49 MPa • {32 ± 5 kg/cm2}
NO
Is PPC pressure normal? (At PPC pressure inlet of control valve)
YES
9 Does spool move smoothly?
NO
YES To 12 on next page
20-840
To 10 on next page
PC78MR-6
H-26
TROUBLESHOOTING
From 8 on previous page
Cause
From 9 on previous page
Remedy
10 NO
Does pressure compensation valve move smoothly?
Defective pressure compensation valve
Repair or replace
Defective unload valve
Repair or replace
YES
11 NO
Does unload valve move smoothly?
YES
Large leakage through travel motor or swivel joint
12 When PPC circuit check valve is NO replaced, is trouble repaired?
YES
PC78MR-6
Defective PPC valve
Repair or replace
Defective PPC circuit check valve
Replace
20-841
H-27
TROUBLESHOOTING
H-27 Machine cannot be steered sharply or steering force is insufficient Cause
Remedy
1 Does engine speed lower (extremely only when machine is steered during travel)?
NO
YES
Defective pump servo
Repair or replace
Defective travel junction variable choke valve
Repair or replace
Malfunction pump merge-divider valve
Repair or replace
Malfunction of logic valve
Repair or replace
Defective PPC
Repair or replace
Malfunction of spool
Repair or replace
Defective unload valve
Repair or replace
2 Is pressure at top PP pressure pickup port of control valve same as port pressure?
NO
YES
3 Does spool of travel junction NO variable choke valve move smoothly and is hole free from clogging?
YES
4 Does pump merge-divider spool move smoothly and is hole free from clogging?
NO
YES
5 Is drive pump pressure of inside motor normal? (Inside pump pressure must be below above 10 NO MPa {100 kg/cm2} while machine is turning on flat concrete with turning radius of about 5 m.)
YES
6 NO
Is inside PPC pressure low?
YES
7 NO
Does spool move smoothly?
YES
8 When main relief circuit check valve is replaced, is trouble repaired?
YES
20-842
NO
Defective counterbalance valve of Repair or travel motor or swivel joint replace Defective main relief circuit check valve
Repair or replace
PC78MR-6
H-28
TROUBLESHOOTING
H-28 Travel speed does not change at all or does not change quickly Cause
Remedy
1 • 31.4 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle
NO
Is output of 2nd travel speed selection solenoid valve normal?
Electric trouble in defective 2nd travel speed selection solenoid valve, 2nd travel speed selection switch, etc.
Repair or replace
Malfunction caused by clogging
Repair or replace
Defective swivel joint
Repair or replace
YES
2 Is outlet choke of 2nd travel speed NO selection solenoid valve free from clogging?
YES
3 Is output pressure of 2nd travel speed selection solenoid valve at travel motor inlet normal?
YES
PC78MR-6
NO
Defective travel motor or 2nd travel Repair or speed selection solenoid valve replace piston
20-843
H-29
TROUBLESHOOTING
H-29 Machine does not travel Cause
1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
Remedy
NO
Does pump pressure rise to relief pressure?
YES
2 Is foreign matter drained from final NO drive?
YES
Defective final drive
Repair or replace
Defective counterbalance valve
Repair or replace
Defective undercarriage
Repair or replace
Defective travel motor (Motor, parking brake system)
Repair or replace
3 NO
Does counterbalance valve of travel motor operate smoothly?
YES • When driven on flat concrete with engine at full throttle, if pressure is below 11.7 MPa {120 kg/cm2}
• Above 3.14 ± 0.49 MPa {Above 32 ± 5 kg/cm2} • Run engine at full throttle • Move lever to stroke end
4
YES
See
5
1
NO
Is PPC pressure normal?(At PPC pressure inlet of control valve)
YES
6
1 If machine does not travel on flat concrete with engine at full throttle and pump pressure above about 10 MPa {100 kg/cm2}, perform diagnosis 2.
NO
Is undercarriage deformed or damaged?
Does travel spool move smoothly?
NO
Malfunction of spool
YES
7 Does pressure compensation valve NO move smoothly?
Defective pressure compensation valve
YES
8 NO
Does unload valve move smoothly?
YES
• Drive machine with boom PPC pressure (Return piping immediately after testing)
20-844
Defective unload valve
Repair or replace
Defective travel motor or swivel joint
Repair or replace
9 When PPC hose is replaced with boom hose on control valve side, does PPC pressure rise?
YES
NO
Defective PPC circuit check valve
Defective PPC valve
PC78MR-6
TROUBLESHOOTING
H-29
H-29 Supplement Relationship between PPC circuit check valve and "Machine does not travel" As shown below, PPC circuit check valves (1) – (4) are installed to pick up the changeover signal pressure for the pump merge-divider valve. If the checking function of these check valves is lost, the machine may not travel. Example: When checking function of (1) is lost • Normal operations: "Left forward travel", "Left forward travel + Right forward travel", "Left forward travel + Right reverse travel" • Operations where machine may not travel: "Left reverse travel", "Right forward travel", "Right reverse travel", "Left reverse travel + Right forward travel", "Left reverse travel + Right reverse travel"
PC78MR-6
20-845
H-30, H-31
TROUBLESHOOTING
H-30 Overrun of travel is large Cause
Remedy
1 Does PPC pressure lower immediately NO after lever is returned? (At PPC pressure inlet of control valve)
Defective PPC
Repair or replace
Malfunction of spool
Repair or replace
Defective suction valve
Repair or replace
Defective counterbalance valve
Repair or replace
Defective check valve
Repair or replace
Defective travel motor
Repair or replace
YES
2 NO
Does spool move smoothly?
YES
3 NO
When suction valve is replaced, is trouble repaired?
YES
4 NO
Does travel motor counterbalance valve move smoothly?
YES
5 Does travel motor check valve move smoothly?
YES
NO
H-31 Travel hydraulic drift is large Cause
Remedy
Defective parking brake or parking Repair or brake valve of travel motor replace
20-846
PC78MR-6
H-32
TROUBLESHOOTING
H-32 Fine controllability or response is low Cause
Remedy
1 When air is bled from PPC, is trouble NO repaired?
YES
Air in PPC
Bleed PPC
2 Is pressure at top PP pressure pickup NO port of control valve same as port pressure?
YES
3 Does spool of pump merge-divider NO valve move smoothly and is hole free from clogging?
YES
Malfunction of pump merge-divider Repair or valve replace Defective logic valve
Repair or replace
Malfunction of unload valve
Repair or replace
Malfunction of pressure compensation valve
Repair or replace
Malfunction of spool
Repair or replace
Defective travel motor
Repair or replace
Defective PPC
Repair or replace
4 NO
Does unload valve move smoothly and is hole free from clogging?
YES
5 NO
Does pressure compensation valve move smoothly?
YES
6 NO
Does spool move smoothly?
YES
7 When PPC valve is replaced, is trouble repaired?
YES
PC78MR-6
NO
20-847
H-33
TROUBLESHOOTING
H-33 Swing speed or power is low (Work equipment, travel, and blade operations are normal) a If there is any other trouble in the work equipment, travel system, or blade system, see H-1. Cause
Remedy
1 NO
When work equipment is relieved, does speed rise?
YES
Defective boom assist valve
Repair or replace
NO
Defective motor unit, brake, or swing machinery circle
Repair or replace
NO
Defective swing brake release solenoid
Replace
Malfunction of swing holding brake
Repair or replace
Malfunction of controller
Replace
Clogging of choke Malfunction of slow return valve
Clean repair or replace
Malfunction of spool
Repair or replace
Defective swing motor
Repair or replace
Defective PPC valve
Repair or replace
Clogging of choke
Clean repair or replace
2 • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle
NO
Is swing relief pressure normal?
YES
3 NO
Does pressure rise to near relief pressure during stable swing?
YES
4 Is swing dragging sound heard?
YES
5 Is swing brake release pressure output?
YES
6 When controller is replaced, is trouble NO repaired?
YES
7 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle.
Is PPC pressure at PPC control valve NO normal?
YES
8 When fixed choke of swing PPC slow- NO return valve is cleaned, is trouble repaired?
YES
9 NO
Does spool move smoothly?
YES
10 When choke of swing PPC line is cleaned, is trouble repaired?
NO
YES
To 11 on next page
20-848
PC78MR-6
H-33
TROUBLESHOOTING
Cause
From 2 on previous page
Remedy
11 When safety valve of swing motor is adjusted or replaced, is trouble repaired?
NO
YES
Defective safety valve
Adjust or replace
Defective check valve or suction valve
Repair or replace
Malfunction of reverse prevention valve
Repair or replace
12 When check valve and suction valve NO of swing motor are replaced, is trouble repaired?
YES
13 When reverse prevention valve is replaced, is trouble repaired?
YES
PC78MR-6
NO
20-849
H-34
TROUBLESHOOTING
H-34 Machine does not swing (Work equipment, travel, and blade operations are normal) a If there is any other trouble in the work equipment, travel system, or blade system, see H-1. a Carry out the following troubleshooting, if the electric system is normal. (If the electric system is defective, carry out E first.) a) Swing speed or power is low in both directions Cause
Remedy
1 When swing operation and operation NO other than boom RAISE operation are executed, does machine move?
YES
Defective LS select valve
Replace
Defective pressure compensation valve
Replace
2 Does pressure compensation valve move smoothly and is hole free from clogging?
NO
YES
3 • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle.
NO
Is swing relief pressure normal?
YES
4 kg/cm2}
• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle
Is swing holding brake relief pressure NO normal? (At motor inlet)
YES
Malfunction of swing holding brake solenoid valve Malfunction of motor unit, brake, or swing machinery
5 NO
Is swing motor turning? (Judge by sound)
YES
Damage of motor shaft or swing machinery
Repair or replace
Defective safety valve
Repair or replace
Go to diagnosis No. 6
—
Defective check valve or suction valve
Clean repair or replace
6 When safety valve of swing motor is adjusted or replaced, is trouble repaired?
NO
YES
7 When check valve and suction valve of swing motor are adjusted or replaced, is trouble repaired?
YES
20-850
NO
PC78MR-6
H-34
TROUBLESHOOTING
b) Swing speed or power is low in either direction Cause
Remedy
1 • 26.5 ± 1.47 MPa {270 ± 15 kg/cm2} • Run engine at full throttle
NO
Is swing relief pressure normal?
YES
2 • 3.14 ± 0.49 MPa {32 ± 5 kg/cm2} • Run engine at full throttle Note that swing timer is set to 5 seconds
Are swing brake release pressures on NO both sides normal? (At solenoid outlet)
YES
Defective swing motor or swing machinery circle
Replace
Malfunction of spool
Repair or replace
Disconnection of wiring harness
Repair or replace
Malfunction of spool
Repair or replace
Defective check valve or suction valve
Repair or replace
3 • Since motor may be broken, operate in fine control mode
When lever is moved to right and left, NO does work equipment move for 5 seconds?
YES
4 When check valve and suction valve NO of swing motor are replaced, is trouble repaired?
YES
PC78MR-6
20-851
H-35
TROUBLESHOOTING
H-35 Swing acceleration is low a) Swing acceleration is low in both directions Cause
Remedy
1 When swing motor safety valve is replaced, is trouble repaired?
YES
NO
Execute diagnosis in H-33, H-40
Defective swing motor safety valve Replace
b) Swing acceleration is low in either direction Cause
Remedy
Execute diagnosis in H-33, H-40
20-852
PC78MR-6
H-36
TROUBLESHOOTING
H-36 Overrun of swing is large a) Overrun of swing is large in both directions Cause
Remedy
1 • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle
NO
Is swing relief pressure normal?
YES
Defective swing motor safety valve Replace Repair or replace
Go to b)
b) Overrun of swing is large in either direction Cause
Remedy
1 NO
Does control valve spool move smoothly?
Malfunction of control valve spool
Repair or replace
Defective swing motor suction valve
Repair or replace
Defective reverse prevention valve
Repair or replace
Defective swing motor check valve
Repair or replace
Defective PPC valve
Repair or replace
YES
2 NO
When swing motor suction valve is replaced, is trouble repaired?
YES
3 NO
When reverse prevention valve is replaced, is trouble repaired?
YES
4 NO
When swing motor check valve is replaced, is trouble repaired?
YES
5 When swing PPC slow-return valve, swing PPC line, and swing PPC circuit choke are cleaned, is trouble repaired?
YES
PC78MR-6
NO
Clogging of swing PPC slow-return Repair or valve, swing PPC line choke, or replace swing PPC circuit choke
20-853
H-37, H-38
TROUBLESHOOTING
H-37 Large shock is made when machine stops swinging Cause
Remedy
1 NO
Does control valve spool move smoothly?
Malfunction of control valve spool
Repair or replace
Go to H-36
Replace
Defective swing motor safety valve
Repair or replace
YES
2 NO
When swing motor safety valve is replaced, is trouble repaired?
YES
H-38 Large abnormal sound is made when machine stops swinging Cause
Remedy
1 NO
When safety valve is replaced, is trouble repaired?
Defective swing motor safety valve Replace
YES
2 NO
When suction valve is replaced, is trouble repaired?
YES
Defective swing motor suction valve
Repair or replace
Defective reverse prevention valve
Repair or replace
Defective swing motor, swing machinery, or swing circle
Repair or replace
Defective swing machinery
Repair or replace
3 NO
When reverse prevention valve is replaced, is trouble repaired?
YES
4 Is foreign matter drained from final drive?
YES
20-854
NO
PC78MR-6
H-39
TROUBLESHOOTING
H-39 Swing hydraulic drift is large a Check that the emergency swing brake release switch is turned OFF. Cause
Remedy
1 When connector of swing pressure switch is disconnected, is trouble repaired?
NO
YES
Defective swing pressure switch
Replace
Defective controller or wiring
Replace
Defective swing motor brake
Repair or replace
Malfunction of solenoid
Replace valve assembly
2 When connector of swing brake release solenoid is disconnected, is trouble repaired?
NO
YES
3 When hose of swing brake release line is disconnected, is trouble repaired?
YES
PC78MR-6
NO
20-855
H-40
TROUBLESHOOTING
H-40 Fine controllability or response of swing is low Cause
Remedy
1 When air is bled from PPC, is trouble NO repaired?
YES
Air in PPC
Bleed Air
2 Is pressure at top PP pressure pickup NO port of control valve same as port pressure?
YES
3 Does spool of pump merge-divider NO valve move smoothly and is hole free from clogging?
YES
Malfunction of pump merge-divider Repair or valve replace Malfunction of logic valve
Repair or replace
Malfunction of unload valve
Repair or replace
Malfunction of pressure compensation valve
Repair or replace
Malfunction of spool
Repair or replace
Defective travel motor
Repair or replace
Defective PPC valve
Repair or replace
4 NO
Does unload valve move smoothly and is hole free from clogging?
YES
5 Does pressure compensation valve move smoothly and is hole free from clogging?
NO
YES
6 NO
Does spool move smoothly?
YES
7 When PPC valve is replaced, is trouble repaired?
YES
20-856
NO
PC78MR-6
H-41
TROUBLESHOOTING
H-41 Blade speed or power is low (Work equipment, travel, and swing operations are normal) a If there is any other trouble in the work equipment, travel system, or swing system, see H-1. Cause
Remedy
1 kg/cm2}
• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle
NO
Is blade PPC pressure normal?
Defective PPC valve
Repair or replace
Go to diagnosis 5
—
Malfunction of check valve in spool or clogging of hole of spool
Repair or replace
Flattened or deformed hose
Replace
Execute diagnosis in H-43 (Hydraulic drift of blade is large)
—
Leakage in control valve (Leakage from line between swing valve and blade valve)
Repair or replace
YES
2 • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle
NO
Is blade LOWER relief pressure normal?
YES
3 NO
Does pump pressure reach relief pressure during operation?
YES
4 NO
Is hose between control valve and cylinder flattened or deformed?
YES
5 Is hydraulic drift normal?
YES
PC78MR-6
NO
20-857
H-42
TROUBLESHOOTING
H-42 Blade does not move (Work equipment, travel, and swing operations are normal) a If there is any other trouble in the work equipment, travel system, or swing system, see H-1. a) Blade does not rise Cause
Remedy
1 kg/cm2}
• 3.14 ± 0.49 MPa {32 ± 5 • Run engine at full throttle
NO
Is blade PPC pressure normal?
Defective PPC valve
Repair or replace
Deformed cylinder or work equipment
Repair or replace
Malfunction of control valve spool
Repair or replace
Flattened or deformed hose
Replace
YES
2 • 21.08 ± 1.47 MPa {215 ± 15 kg/cm2} • Run engine at full throttle
NO
Is blade LOWER relief pressure normal?
YES
3 NO
Is cylinder or work equipment deformed?
YES
4 NO
Is hose flattened or deformed?
YES
5 Check hydraulic drift by H-41.
YES If trouble is not repaired by H-41 Leakage in control valve (Large leakage from line between swing valve and blade valve)
20-858
Repair or replace
PC78MR-6
H-42
TROUBLESHOOTING
b) Blade does not lower Cause
Remedy
1 NO
Is blade held in air?
YES
2 NO
Is blade PPC normal?
Defective blade PPC valve
Repair or replace
Deformed cylinder or work equipment
Repair or replace
Malfunction of spool
Repair or replace
Flattened or deformed hose
Replace
Execute diagnosis in H-41 (Hydraulic drift of blade is large)
Repair or replace
YES
3 NO
Is cylinder or work equipment deformed?
YES
4 NO
Is hose flattened or deformed?
YES
5 Is it impossible to raise machine by bracing blade on ground?
YES
PC78MR-6
20-859
H-43
TROUBLESHOOTING
H-43 Hydraulic drift of blade is large Cause
Remedy
1 NO
Is leakage from cylinder normal?
Defective cylinder piston packing
Repair or replace
Large leakage through swivel joint
Repair or replace
YES
2 When hose is disconnected from valve outlet and plugged, is hydraulic drift large?
NO
YES
3 • If blade is held in air and hydraulic drift is large
NO
When centralized safety valve is replaced, is trouble repaired?
YES
Defective centralized safety valve Replace
4 NO
When suction valve is replaced with plug, is trouble repaired?
YES
Low oil-tightness of spool
Repair or replace
Defective suction safety valve
Repair or replace
Low oil-tightness of spool
Repair or replace
Defective blade safety valve
Replace
5 • If hydraulic drift is large when machine body is raised with blade
When blade safety valve is replaced, is trouble repaired?
YES
20-860
NO
PC78MR-6
H-44
TROUBLESHOOTING
H-44 Fine controllability or response of blade is low Cause
Remedy
1 When air is bled from PPC, is trouble NO repaired?
YES
Air in PPC
Bleed Air
2 Is pressure at top PP pressure pickup NO port of control valve same as port pressure?
YES
3 Does spool of pump merge-divider NO valve move smoothly and is hole free from clogging?
YES
Malfunction of pump merge-divider Repair or valve replace Malfunction of logic valve
Repair or replace
Malfunction of unload valve
Repair or replace
Malfunction of pressure compensation valve
Repair or replace
Malfunction of spool
Repair or replace
Defective travel motor
Repair or replace
Defective PPC
Repair or replace
4 NO
Does unload valve move smoothly and is hole free from clogging?
YES
5 Does pressure compensation valve move smoothly and is hole free from clogging?
NO
YES
6 NO
Does spool move smoothly?
YES
7 When PPC valve is replaced, is trouble repaired?
YES
PC78MR-6
NO
20-861
TROUBLESHOOTING FOR MACHINE MONITOR SYSTEM (M MODE) Action taken by controller when trouble occurs and problems on machine ............................................... 20-902 Electric circuit diagram of M mode system ................................................................................................ 20-904 M- 1 [E101] (Error history data are abnormal) is displayed ..................................................................... 20-906 M- 2 [E108] (Engine coolant temperature is 105 ºC) is displayed ........................................................... 20-907 M- 3 [E112] (Wiper forward output is shorted) is displayed ..................................................................... 20-907 M- 4 [E113] (Wiper reverse output is shorted) is displayed ..................................................................... 20-907 M- 5 [E114] (Contact with washer output of 24 V) is displayed ............................................................... 20-907 M- 6 [E115] (Wiper does not start wiping in 10 seconds) is displayed ..................................................... 20-907 M- 7 [E116] (Wiper is not retracted in 10 seconds) is displayed .............................................................. 20-907 M- 8 Monitor panel segments do not light up at all for 3 seconds after starting switch is turned ON ...... 20-908 a) Monitor panel segments do not light up at all .............................................................................. 20-908 b) Some monitor panel segments do not light up ............................................................................ 20-908 M- 9 When starting switch is set to ON position, all monitor panel segments light up but do not go off ..... 20-910 M-10 While preheating is not executed, "Preheater monitor" lights up ................................................... 20-910 M-11 When starting switch is set to ON position and engine is started, basic check items flash ............. 20-911 a) Alternator system ........................................................................................................................ 20-911 b) Engine oil system ........................................................................................................................ 20-912 M-12 When starting switch is set to ON position (but engine is stopped), caution items and emergency stop items (excluding battery and engine oil) flash ....................................................... 20-913 a) Alternator system ........................................................................................................................ 20-913 b) Engine oil pressure sensor system ............................................................................................. 20-914 M-13 When starting switch is set to ON position and engine is started, caution items and emergency stop items flash (When there is not abnormality in inspection items and engine before troubleshooting, however) ........................................................................................ 20-915 a) "Engine oil" flashes ..................................................................................................................... 20-915 b) "Charge level" flashes ................................................................................................................. 20-915 c) "Coolant temperature" flashes ..................................................................................................... 20-916 d) "Fuel level" flashes ...................................................................................................................... 20-917 M-14 When starting switch is set to ON position (but engine is stopped), buzzer does not sound for 1 second While caution item is flashing, buzzer does not sound .................................................................... 20-918 M-15 Monitor plane lamp for nighttime is not turned on (LC display is normal) ....................................... 20-919 M-16 Coolant temperature gauge does not rise ....................................................................................... 20-920 M-17 Coolant temperature gauge is not displayed (Gauge does not rise to 1st line during operation) ..... 20-920 M-18 Fuel level gauge always displays full .............................................................................................. 20-921 M-19 Fuel level gauge is not displayed .................................................................................................... 20-921 M-20 While engine is running, service meter does not advance .............................................................. 20-922 M-21 Trouble in fuel level sensor .............................................................................................................. 20-923 M-22 Trouble in coolant temperature sensor ............................................................................................ 20-924 M-23 Wiper does not operate or operates while wiper switch is turned off .............................................. 20-925 a) Wiper does not operate ............................................................................................................... 20-925 b) Wiper operates while wiper switch is turned off .......................................................................... 20-925 M-24 Washer motor does not operate or operates while washer switch is turned off .............................. 20-928 a) Washer motor does not operate .................................................................................................. 20-928 b) Washer operates while wiper switch is turned off ....................................................................... 20-928 a When a connector is disconnected and a T-adapter is inserted for troubleshooting or when the T-adapter is removed and the connector is returned, if the service code "E" is not displayed, the condition has returned to normal. a If the starting switch was turned off after the trouble occurred, turn the starting switch ON and check that the service code displays "E" at the head. (If "E" is not displayed, the condition has returned to normal.) a Before carrying out the troubleshooting, check that all the related connectors are properly inserted. a Always connect any disconnected connectors before going on to the next step. PC78MR-6
20-901
ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE
TROUBLESHOOTING
ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE Service Code
Troubled System
—
E101
Error history data are abnormal
1. 2. 3. 4.
—
E108
Engine coolant temperature is 105 °C
1. Coolant temperature sensed by coolant temperature sensor is above 105 °C
Short circuit in forward system of wiper motor drive
1. Short circuit or short circuit with chassis ground in wiring between 2. Short circuit or short circuit with chassis ground in wiring between monitor panel P01 (Female) (9) – wiper motor W04 (Female) (3) 3. Defective monitor panel
Short circuit in reverse system of wiper motor drive
1. Short circuit or short circuit with chassis ground in wiper motor 2. Short circuit or short circuit with chassis ground in wiring between monitor panel P01 (Female) (10) – wiper motor W04 (Female) (1) 3. Defective monitor panel
Short circuit in windshield washer drive system
1. Short circuit in washer motor 2. Short circuit with power source in wiring harness between monitor panel P01(Female) (3) – M31 (Female) (1) 3. Defective monitor panel
Wiper does not start wiping in 10 seconds
1. Defective wiper motor 2. Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring harness between monitor panel P01 (Female) (5) – W04 (6) 3. Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring harness between monitor panel P01 (Female) (12) – W04(4) 4. Defective monitor panel
Wiper is not retracted in 10 seconds
1. Defective wiper motor 2. Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring harness between monitor panel P01 (Female) (5) – W04 (6) 3. Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring harness between monitor panel P01 (Female) (12) – W04 (4) 4. Defective monitor panel
User Code
—
—
—
—
—
20-902
E112
E113
E114
E115
E116
Contents of Trouble Trouble in internal memory Overvoltage (Above 36 V) Undervoltage (Above 12 V) Disconnection of connector
PC78MR-6
ACTION TAKEN BY CONTROLLER WHEN TROUBLE OCCURS AND PROBLEMS ON MACHINE
TROUBLESHOOTING
Normal Condition (Voltage, Current, Resistance)
•
•
Resistance between M18 (Male) (1) – (2): Min. 3.70 kz (With engine started)
Problem That Appears on Machine When There is Abnormality
—
1. Service code cannot be cleared
—
1. If abnormality is detected continuously, coolant temperature caution lamp flashes and buzzer sounds. 2. If abnormality is detected continuously, engine speed is set to low idling.
Voltage between W04 (3) – (5): Max. 3 V
a Repeated at regular intervals.
•
Action Taken By Controller When Abnormality is Detected
20 – 30 V
Stops outputting to wiper motor
Wiper stops
Same as [E112]
Same as [E112]
Voltage between W04 (1) – (5): Max. 3 V
a Repeated at regular intervals.
20 – 30 V
•
Voltage between P01 (3) – chassis ground 1. Stops outputting to When washer switch is turned OFF: 20 – 30 V washer motor When washer switch is turned ON: Max. 1 V
1. Stops outputting to washer motor
•
Timing chart of setting wiper switch to ON and INT is conformed to Tables 1 and 2 in M-23
Same as [E112]
Same as [E112]
•
Timing chart of setting wiper switch to ON and INT is conformed to Tables 1 and 2 in M-23
Same as [E112]
Same as [E112]
PC78MR-6
20-903
TROUBLESHOOTING
ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM
ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM (1/2)
20-904
PC78MR-6
TROUBLESHOOTING
ELECTRIC CIRCUIT DIAGRAM OF M MODE SYSTEM
(2/2)
PC78MR-6
20-905
M-1
TROUBLESHOOTING
M-1 [E101] (Error history data are abnormal) is displayed a If connector P01, connector K1, fuse 18, connector M6, connector M2, connector M27, battery relay terminal B, or battery terminal in the monitor panel power supply system is disconnected or connected for troubleshooting, this error is displayed. This phenomenon does not indicate an actual error, however. (When the monitor panel power circuit is broken by turning off the starting switch.) a If the service code is displayed again after the resetting operation, check by the following procedure. Cause • After resetting operation, operate machine normally and observe its condition for a while. (See Note 1.)
Remedy
1 NO
After "resetting operation", is service code displayed again?
Normal
—
Disconnection, defective contact, or short circuit with chassis ground in wiring harness between battery – battery relay B – M27 (1), (2) – P01 (Female) (8)
Repair or replace
Defective monitor panel
Replace
YES
2 • Turn starting switch OFF • 20 – 30 V
Is voltage between P01 (8) – chassis ground normal?
YES
NO
Note: Resetting operation: Turn the starting switch to OFF position, then turn it to the ON position again, with the buzzer cancel switch pushed, and keep pressing the buzzer cancel switch for 5 seconds. (All the service codes saved in the memory are deleted by this operation.) M-1 Electrical circuit diagram of each system
20-906
PC78MR-6
M-2, M-3, M-4, M-5, M-6, M-7
TROUBLESHOOTING
M-2 [E108] (Engine coolant temperature is 105 ºC) is displayed Cause
Remedy
1 NO
Does coolant temperature gauge of monitor indicate red range and is caution lamp flashing?
YES
See M-13, c)
—
Trouble in engine unit (See Note 1)
—
Defective monitor panel
Replace
2 • Turn starting switch ON
Is "E" attached to head of service code?
NO
YES
Note: The display of the monitor panel has been reset normally. Since the coolant temperature sensor detected coolant temperature above 105°C, remove the cause of that temperature rise by troublshooting the engine unit.
M-3 [E112] (Wiper forward output is shorted) is displayed a See M-23.
M-4 [E113] (Wiper reverse output is shorted) is displayed a See M-23.
M-5 [E114] (Contact with washer output of 24 V) is displayed a See M-24.
M-6 [E115] (Wiper does not start wiping in 10 seconds) is displayed a See M-23.
M-7 [E116] (Wiper is not retracted in 10 seconds) is displayed a See M-23.
PC78MR-6
20-907
M-8
TROUBLESHOOTING
M-8 Monitor panel segments do not light up at all for 3 seconds after starting switch is turned ON a Check that fuses 13 and 18 are normal. a) Monitor panel segments do not light up at all Cause
Remedy
1 • Turn starting switch ON. • 20 – 30 V
Is voltage between P01 (8) and (6), (7) normal?
NO
YES
2 • Turn starting switch ON • 20 – 30 V
NO
Is voltage between P01 (1), (2) and (6), (7) normal?
YES
3 • Turn starting switch OFF. • Max. 1 z • Disconnect P01.
Is resistance between P01 (female) (6), (7) and chassis ground normal?
NO
YES
Disconnection or defective contact in wiring harness between P01 (female) (6), (7) – chassis ground
Repair or replace
Defective monitor panel
Replace
Disconnection or defective contact in wiring harness between fuse 13 – P01 (female) (1), (2)
Repair or replace
Disconnection or defective contact in wiring harness between fuse box – battery relay terminal M
Repair or replace
Disconnection or defective contact in wiring harness between fuse 18 – P01 (female) (8)
Repair or replace
Disconnection or defective contact in wiring harness between fuse box – battery relay terminal B
Repair or replace
4 • Turn starting switch ON. • 20 – 30 V
Is voltage between fuse 13 and chassis ground normal?
NO
YES
5 • Turn starting switch ON. • 20 – 30 V
Is voltage between fuse 18 and chassis ground normal?
YES
NO
b) Some monitor panel segments do not light up Cause Defective monitor panel
20-908
Remedy Replace
PC78MR-6
TROUBLESHOOTING
M-8
M-8 a) Electrical circuit diagram of each system
PC78MR-6
20-909
M-9,10
TROUBLESHOOTING
M-9 When starting switch is set to ON position, all monitor panel segments light up but do not go off Cause Defective monitor panel
Remedy Replace
M-10 While preheating is not executed, "Preheater monitor" lights up Cause
Remedy
1 • Disconnect terminal R1 • Turn starting switch ON • Max. 1 V
NO
Is voltage between starting switch R1 – chassis ground normal?
Defective starting switch
Replace
Short circuit with power source in wiring harness between starting switch R1 – P02 (Female) (18)
Repair or replace
Defective monitor panel
Replace
YES
2 • Turn starting switch ON • Max. 1 V
Is voltage between P02 (18) – chassis ground normal?
YES
NO
M-10 Electrical circuit diagram of each system
20-910
PC78MR-6
M-11
TROUBLESHOOTING
M-11 When starting switch is set to ON position and engine is started, basic check items flash a Inspect both alternator system and engine hydraulic system. a) Alternator system a Check monitoring code "43". If it is 100 or larger while the engine speed is above the medium level, the monitor panel is defective. Cause
Remedy
1 • Run engine above medium speed level • 20 – 30 V
Is voltage between alternator terminal R – chassis ground normal?
NO
Defective alternator
Replace
Disconnection or defective contact in wiring harness between alternator terminal R – P02 (Female) (11)
Repair or replace
Defective monitor panel
Replace
YES
2 • Run engine above medium speed level • 20 – 30 V
Is voltage between P02 (11) – chassis ground normal?
YES
NO
M-11 a) Electrical circuit diagram of each system
PC78MR-6
20-911
M-11
TROUBLESHOOTING
b) Engine oil system a Carry out the following troubleshooting when the engine oil pressure is normal. a Check bit (3) of monitoring code "46". If it is lighting up, the monitor panel is defective. Cause
Remedy
1 • Run engine at low speed
When engine speed is low, if oil pressure sensor terminal T6 is disconnected, does error disappear?
NO
Defective oil pressure sensor (Low pressure)
Replace
2 • Turn starting switch OFF • Disconnect sensor wiring harness and P02
Is there continuity between P02 (7) – chassis ground normal?
YES
NO
Short circuit with chassis ground Repair or in wiring harness between P02 (Female) (7) – sensor terminal T6 replace Defective monitor panel
Replace
M-11 b) Electrical circuit diagram of each system
20-912
PC78MR-6
M-12
TROUBLESHOOTING
M-12 When starting switch is set to ON position (but engine is stopped), caution items and emergency stop items (excluding battery and engine oil) flash a Inspect both alternator system and engine hydraulic system. a) Alternator system a Check monitoring code "43". If it is 100 or larger while the engine speed is above the medium level, the monitor panel is defective. Cause
Remedy
1 • Disconnect terminal R • Turn starting switch ON • Max. 1 V
NO
Is voltage between alternator terminal R – chassis ground normal?
Defective alternator
Replace
Short circuit with power source in wiring harness between P02 (Female) (11) – alternator terminal R
Repair or replace
Defective monitor panel
Replace
YES
2 • Disconnect P02 • Turn starting switch ON • Max. 1 V
Is voltage between P02 (Female) (11) – chassis ground normal?
YES
NO
M-12 a) Electrical circuit diagram of each system
PC78MR-6
20-913
M-12
TROUBLESHOOTING
b) Engine oil pressure sensor system a Carry out the following troubleshooting when the engine oil pressure is normal. a Check bit (3) of monitoring code "46". If it is lighting up, the monitor panel is defective. Cause
Remedy
1 • Turn starting switch OFF • Disconnect sensor terminal T6
NO
Is there continuity between sensor terminal T6 – chassis ground?
Defective oil pressure sensor
Replace
Disconnection or defective contact in wiring harness between P02 (Female) (7) – sensor terminal T6
Repair or replace
Defective monitor panel
Replace
YES
2 • Turn starting switch OFF • Disconnect P02 – sensor terminal T6
Is there continuity between P02 (Female) (11) – sensor terminal T6?
NO
YES
M-12 b) Electrical circuit diagram of each system
20-914
PC78MR-6
M-13
TROUBLESHOOTING
M-13 When starting switch is set to ON position and engine is started, caution items and emergency stop items flash (When there is not abnormality in inspection items and engine before troubleshooting, however) a) "Engine oil" flashes a Before carrying out the troubleshooting, check that the engine oil pressure is normal. Cause See M-11-b)
Remedy —
b) "Charge level" flashes Cause See M-11-a)
PC78MR-6
Remedy —
20-915
M-13
TROUBLESHOOTING
c) "Coolant temperature" flashes a Before carrying out the troubleshooting, check that the coolant temperature is normal. Cause
Remedy
1 • Start engine • Set engine speed to medium or higher
NO
Is coolant temperature gauge in red range?
Defective monitor panel
Replace
Defective coolant temperature sensor system (See M-22)
—
Disconnection or defective contact in wiring harness between P02 (Female) (1) – M18 (Female) (1)
Repair or replace
Disconnection or defective contact in wiring harness between M18 (Female) (2) – chassis ground
Repair or replace
YES
2 • Start engine
NO
When M18 is disconnected, does gauge indicate only level 1 (Lowest line)?
YES
3 • Turn starting switch OFF • Disconnect P02 and M18 • Max. 1 z
Is resistance between P02 (Female) (1) – M18 (Female) (1) normal?
YES
NO
M-13 c) Electrical circuit diagram of each system
20-916
PC78MR-6
M-13
TROUBLESHOOTING
d) "Fuel level" flashes a Before carrying out the troubleshooting, check that there is fuel in the fuel tank. Cause
Remedy
1 • Start engine
NO
Is fuel level gauge in red range?
Defective monitor panel
Replace
Defective fuel level sensor system (See M-21)
—
Disconnection or defective contact in wiring harness between P02 (Female) (2) – M9 (Female) (1)
Repair or replace
Defective monitor panel
Repair or replace
YES
2 • Start engine • Wait for 2 minutes. (Since fuel level fluctuates, its display is delayed.)
When M9 (Female) (1) is connected to chassis ground, do gauge segments light up to level 9 (Right end)?
NO
YES
3 • Connect M9 (Female) (1) to chassis ground • Turn starting switch ON • Max. 0.3 V
Is voltage between P02 (2) – chassis ground normal?
YES
NO
M-13 d) Electrical circuit diagram of each system
PC78MR-6
20-917
M-14
TROUBLESHOOTING
M-14 When starting switch is set to ON position (but engine is stopped), buzzer does not sound for 1 second While caution item is flashing, buzzer does not sound a Even if the charge level and fuel level among the caution items become abnormal, the buzzer does not sound. a The busdzzer is controlled by the monitor panel and turned on when it is required to sound or when the voltage at P01 (11) is 20 – 30 V. Cause • Turn starting switch OFF • Disconnect K53 • When buzzer cancel switch is ON: Max. 1 z • When buzzer cancel switch is OFF: Min. 1 Mz
Remedy
1 Is resistance between K53 (Female) (1) – (2) normal?
NO
Defective buzzer cancel switch
Replace
YES
2 • Disconnect K53 • Turn starting switch ON • 20 – 30 V
Is voltage between P02 (16) – chassis ground normal?
YES
NO
Disconnection, defective contact, or short circuit with Repair or chassis ground in wiring replace harness between P02 (Female) (16) – K53 (Male) (2) Defective monitor panel
Replace
M-14 Electrical circuit diagram of each system
20-918
PC78MR-6
M-15
TROUBLESHOOTING
M-15 Monitor plane lamp for nighttime is not turned on (LC display is normal) a Carry out the following troubleshooting when the headlamp and working lamp light up normally. Cause
Remedy
1 • Turn starting switch ON • Set monitoring code to "45"
NO
Is bit (4) of monitoring code "45" turned off?
YES
Defective monitor panel
Replace
Disconnection, defective contact in wiring harness between P02 (Female) (19) – K52 (Male) (1)
Repair or replace
Defective monitor panel
Replace
2 • Turn starting switch ON • Turn light switch ON • 20 – 30 V
Is voltage between P02 (19) – chassis ground normal?
NO
YES
M-15 Electrical circuit diagram of each system
PC78MR-6
20-919
M-16, M-17
TROUBLESHOOTING
M-16 Coolant temperature gauge does not rise a When the engine coolant temperature does not rise actually, inspect the engine system. Cause
Remedy
1 • Disconnect M18 • Turn starting switch ON
When short connector is connected to M18 (Female), does gauge rise 1 level by 1 and go off at last?
NO
YES
Defective coolant temperature sensor system (See M-22)
—
Disconnection or defective contact in wiring harness between P02 (Female) (1) – M18 (Female) (1)
Repair or replace
Disconnection or defective contact in wiring harness between M18 (Female) (2) – chassis ground
Repair or replace
Defective monitor panel
Replace
2 • Turn starting switch OFF • Disconnect P02 and M18
NO
Is there continuity between P02 (Female) (1) – M18 (Female) (1)?
YES
3 • Turn starting switch OFF • Disconnect M18
NO
Is resistance between M18 (Female) (2) – chassis ground normal?
YES
M-17 Coolant temperature gauge is not displayed (Gauge does not rise to 1st line during operation) Cause
Remedy
1 • Disconnect M18 • Turn starting switch ON
NO
When M18 is disconnected, is gauge displayed?
YES
Defective coolant temperature sensor system (See M-22)
—
Defective monitor panel
Replace
Short circuit with chassis ground in wiring harness between P02 (Female) (1) – M18 (Female) (1)
Repair or replace
2 • Turn starting switch ON • Disconnect P02 and M18
Is there continuity between P02 (Female) (1) – chassis ground?
YES
NO
M-16, M-17 Electrical circuit diagram of each system
20-920
PC78MR-6
M-18, M-19
TROUBLESHOOTING
M-18 Fuel level gauge always displays full a Before carrying out the troubleshooting, see if the fuel tank is actually full. Cause • Turn starting switch ON • Wait for 2 minutes. (Since fuel level fluctuates, its display is delayed.)
Remedy
1 NO
When M9 is disconnected, does gauge rise 1 level by 1 and go off at last?
YES
Defective fuel level sensor system (See M-21)
—
Defective monitor panel
Replace
Short circuit with chassis ground in wiring harness between P02 (Female) (2) – M9 (Female) (1)
Repair or replace
2 • Turn starting switch OFF • Disconnect P02 and M9
NO
Is there continuity between P02 (Female) (2) – chassis ground?
YES
M-19 Fuel level gauge is not displayed a Before carrying out the troubleshooting, check that there is fuel in the fuel tank. Cause
Remedy
1 • Disconnect M9 • Turn starting switch ON
NO
When M9 (Female) (1) is connected to chassis ground, does gauge display?
YES
Defective fuel level sensor (See M-21)
—
Disconnection or defective contact in wiring harness between M9 (Female) (2) – chassis ground
Repair or replace
Defective monitor panel
Replace
2 • Turn starting switch OFF • Disconnect M9
Is there continuity between M9 (Female) (2) – chassis ground?
NO
YES
M-18, M-19 Electrical circuit diagram of each system
PC78MR-6
20-921
M-20
TROUBLESHOOTING
M-20 While engine is running, service meter does not advance Cause
Remedy
1 • Start engine • Set engine speed to medium or higher
Does charge level caution lamp flash?
YES
20-922
NO
Defective monitor panel
Replace
See M-13 c)
—
PC78MR-6
M-21
TROUBLESHOOTING
M-21 Trouble in fuel level sensor a When carrying out the following troubleshooting, remove the fuel level sensor. Cause
Remedy
1 When float is moved up and down, does resistance between connector (1) – flange change as shown in Table 1?
NO
YES
2 NO
Does arm move smoothly?
Defective sensor (See Note 2)
Replace
Bad contact of connector
Clean or replace connector
Interference of sensor in tank
Replace (See Note 2)
Defective sensor
Replace
Breakage of wiring harness (See Note 3) (Defective clamp) (Application of external force)
Replace sensor
YES
3 Is float cracked, broken off, or scratched badly?
NO
YES
4 Is breakage of wiring harness detected by visual inspection?
NO
YES
Table At upper (FULL) stopper
Approx. 12 or below
At lower (EMPTY) stopper
Approx. 85 – 110z
Note 1. Difference between actual fuel level and level indicated by gauge When the gauge indicates 14 (F), the fuel level is 78 – 100%. When the former indicates 1 (E), the latter is below 14.5%. If the machine body is slanted, the displayed fuel level is different from the actual fuel level. Accordingly, stop the machine on a level place and check the fuel level gauge after waiting for at least 2 minutes. (Since fuel level fluctuates, its display is delayed.) Note 2. Since the sensor may be interfering in the tank or it may be installed wrongly, install it very carefully. Note 3. Check the installation position of the connector for vibration. If it vibrates remarkably, take proper measures to suppress the vibration.
PC78MR-6
20-923
M-22
TROUBLESHOOTING
M-22 Trouble in coolant temperature sensor Cause
Remedy
1 NO
Is resistance between temperature sensor connector (Male) (1) – (2) normal?
YES
Bad contact of connector (See Note 1)
Clean connector or replace sensor
Defective sensor
Replace
Breakage of wiring harness (See Note 2) (Defective clamp) (Application of external force)
Replace sensor
2 Is breakage of wiring harness detected by visual inspection?
NO
YES
Table Normal Approx. 37 – 50 kz Temperature (25 °C) 100 °C
Approx. 3.5 – 4.0 kz
Note 1. If this error is displayed repeatedly, the connector (Female) on the machine side may be defective. Accordingly, inspect the connector and wiring harness on the machine side. Note 2. Check the installation position of the connector for vibration. If it vibrates remarkably, take proper measures to suppress the vibration.
20-924
PC78MR-6
M-23
TROUBLESHOOTING
M-23 Wiper does not operate or operates while wiper switch is turned off a) Wiper does not operate a Check that fuse 14 is normal. a If service code "E112", "E113", "E115", or "E116" is displayed, carry out the following troubleshooting. Cause
Remedy
1 • Close front window • Turn starting switch ON • Set monitoring code to "49"
NO
Does bit (3) of monitoring code "49" light up?
YES • Turn starting switch ON • Set wiper switch to "ON" or "INT" position • Set monitoring code to "49"
2 When wiper switch is set to "ON" or "INT" position, do bits (4), (5) of monitoring code "49" go off?
NO
Defective monitor panel
Replace
Defective wiper motor
Replace
Disconnection, defective contact, short circuit, or short circuit with chassis ground in wiring having improper resistance
Repair or replace
Defective monitor panel
Replace
Defective rear limit switch or opening of front window
Inspection or replace
Disconnection or defective contact in wiring harness having improper resistance
Repair or replace
Defective monitor panel
Replace
YES
3 • Turn starting switch ON
NO
Is voltage between pins of W04 as shown in Table 1?
YES
4 • Turn starting switch OFF • Disconnect P02 and W04
Is voltage between pins of P01 (Female) – W04 (Male) as shown in Table 2?
NO
YES
• Max. 1 z • Turn starting switch OFF • Disconnect terminals (1), (2) of W03.
5 Is resistance between rear limit switch terminals W03 (1) – (2) normal?
NO
YES
6 • Max. 1 z • Turn starting switch OFF • Disconnect terminals (1), (2) of P02 and W03
Is resistance between rear limit switch terminal W03 (1) – P02 (Female) (15), between W03 (2) – chassis ground normal?
NO
YES
b) Wiper operates while wiper switch is turned off Cause
Remedy
1 • Close front window • Turn starting switch ON • Set monitoring code to "49"
NO
Does bit (3) of monitoring code "49" light up?
Defective monitor panel
Replace
Defective monitor panel
Replace
Short circuit with power source in wiring harness between P01 (Female) (9) – W04 (Female) (3) or between P01 (Female) (10) – W04 (Female) (1)
Repair or replace
YES
2 • Turn starting switch ON
When wiper switch is set to "ON" or "INT" position, do bits (4), (5) of monitoring code "49" go off? YES
PC78MR-6
NO
20-925
M-23
TROUBLESHOOTING
Table 1 Timing chart of ON-OFF operation of wiper Symbol
Set Time
Stop time up to next operation
Item
Tia
0.13 sec
Safety circuit during operation of wiper [Safety function (1)]
Tsa
10 sec
Stop time up to retraction of wiper blade
Tip
1.5 sec
Safety circuit during retraction of wiper [Safety function (2)]
Tsp
10 sec
Item
Symbol
Set Time
Stop time up to next operation
Tia
4 sec
Safety circuit during operation of wiper [Safety function (1)]
Tsa
10 sec
Stop time up to retraction of wiper blade
Tip
1.5 sec
Safety circuit during retraction of wiper [Safety function (2)]
Tsp
10 sec
Table 2 Diagnosis 4
Resistance
Between P01 (Female) (10) – W04 (Female) (1) Between P01 (Female) (9) – W04 (Female) (3) Between P01 (Female) (12) – W04 (Female) (4)
Max. 1 z
Between P01 (Female) (6), (7) – W04 (Female) (5) Between P01 (Female) (5) – W04 (Female) (6) Between W04 (Female) (1), (3), (4), (5), (6) – GND
20-926
Min. 1 Mz
PC78MR-6
TROUBLESHOOTING
M-23
M-23 Electrical circuit diagram of each system
PC78MR-6
20-927
M-24
TROUBLESHOOTING
M-24 Washer motor does not operate or operates while washer switch is turned off a) Washer motor does not operate a Check that fuse 4 is normal. a)-1 When [E114] is displayed Cause
Remedy
1 • Max. 1 V • Turn starting switch ON • Disconnect P02 and M31
Is voltage between P01 (Female) (3) – M31 (Female) (1) – chassis ground normal?
NO
Short circuit with power source in wiring harness between P01 (Female) (3) – M31 (Female) (1)
Repair or replace
Defective monitor panel
Replace
YES
a)-2 When [E114] is not displayed Cause
1 • 20 – 30 V • Turn starting switch ON • Disconnect M31
Is voltage between fuse 4 – M31 (Female) (2) – chassis ground normal?
NO
Remedy
Disconnection or defective contact in wiring harness between fuse 4 – M31 (Female) (2)
Repair or replace
Disconnection or defective contact in wiring harness between P01 (Female) (3) – M31 (Female) (1)
Repair or replace
Defective washer motor
Replace
Defective monitor panel
Replace
YES
2 • Max. 1 z • Turn starting switch OFF • Disconnect P01 and M31
NO
Is resistance between P01 (Female) (3) – M31 (Female) (1) normal?
YES
3 • Max. 1 V • Turn starting switch ON • Turn washer switch ON
Is voltage between P01 (Female) (3) – chassis ground normal?
NO
YES
b) Washer operates while wiper switch is turned off Cause
Remedy
1 • Min. 1 Mz • Turn starting switch OFF • Disconnect P02 and M31
Is resistance between M31 (Female) (1) – chassis ground normal?
NO
Short circuit with chassis ground in wiring harness between P01 (Female) (3) – M31 (Female) (1)
Repair or replace
Defective monitor panel
Replace
YES
20-928
PC78MR-6
TROUBLESHOOTING
M-24
M-24 Electrical circuit diagram of each system
PC78MR-6
20-929
30 DISASSEMBLY AND ASSEMBLY METHOD OF USING MANUAL ...................30- 2 PRECAUTIONS WHEN CARRYING OUT OPERATION........................................30- 3 SPECIAL TOOL LIST...................................30- 7 COUNTERWEIGHT Removal and Installation ..........................30-13 INJECTION PUMP Removal....................................................30-14 Installation.................................................30-15 CYLINDER HEAD Removal....................................................30-16 Installation.................................................30-19 MAIN PUMP Removal....................................................30-20 Installation.................................................30-21 CONTROL PUMP Removal and Installation ..........................30-21 ENGINE AND MAIN PUMP Removal....................................................30-22 Installation.................................................30-24 HYDRAULIC OIL COOLER Removal and Installation ..........................30-25 RADIATOR Removal....................................................30-25 Installation.................................................30-26 SWING MOTOR AND SWING MACHINERY Removal and Installation ..........................30-27 SWING MACHINERY Disassembly .............................................30-28 Assembly ..................................................30-30 SWING MOTOR Removal and Installation ..........................30-34 CENTER SWIVEL JOINT Removal....................................................30-34 Installation.................................................30-35 Disassembly and Assembly......................30-36 CONTROL VALVE Removal and Installation ..........................30-37 Assembly ..................................................30-38 WORK EQUIPMENT PPC VALVE Assembly ..................................................30-39 TRAVEL PPC VALVE Assembly ..................................................30-40 HYDRAULIC TANK Removal and Installation ..........................30-42 PC78MR-6
FUEL TANK Removal ................................................... 30-43 Installation ................................................ 30-44 CONTROLLER Removal and Installation.......................... 30-44 MONITOR PANEL Removal and Installation.......................... 30-45 AIR CONDITIONER UNIT Removal ................................................... 30-45 Installation ................................................ 30-46 OPERATOR’S CAB Removal and Installation.......................... 30-47 FLOOR FRAME Removal ................................................... 30-48 Installation ................................................ 30-49 REVOLVING FRAME Removal and Installation.......................... 30-50 SWING CIRCLE Removal and Installation.......................... 30-51 WORK EQUIPMENT Removal ................................................... 30-52 Installation ................................................ 30-53 SWING BRACKET Removal ................................................... 30-54 Installation ................................................ 30-55 STEEL SHOE, RUBBER PAD SHOE, ROAD LINER Expansion and Installation ....................... 30-56 RUBBER SHOE Removal and Installation.......................... 30-57 FINAL DRIVE Removal ................................................... 30-57 Installation ................................................ 30-58 IDLER Assembly.................................................. 30-58 RECOIL SPRING Disassembly............................................. 30-60 Assembly.................................................. 30-61 TRACK ROLLER Disassembly............................................. 30-62 Assembly.................................................. 30-63 HYDRAULIC CYLINDER Disassembly............................................. 30-65 Assembly.................................................. 30-67
30-1
DISASSEMBLY AND ASSEMBLY
METHOD OF USING MANUAL
METHOD OF USING MANUAL 1. When removing or installing unit assemblies (1) When removing or installing a unit assembly, the order of work and techniques used are given for the removal operation; the order of work for the installation operation is not given. (2) Any special techniques applying only to the installation procedure are marked [*1], and the same mark is placed after the relevant step in the removal procedure to indicate which step in the installation procedure it applies to. (Example) REMOVAL OF O O O ASSEMBLY ....................................... Title of operation
k ........................................................................................ Precautions related to safety when carrying out the operation 1. XXXX (1)......................................................................... Step in operation a .................................................................................... Technique or important point to remember when removing XXXX (1). 2. EEE (2): ..................................................................... [*1] Indicates that a technique is listed for use during installation 3. T T T T assembly (3) 6 ............................................................................. See Lubricant and Coolant Table
INSTALLATION OF O O O ASSEMBLY ............................... Title of operation • Carry out installation in the reverse order of removal [*1] ............................................................................. Technique used during installation a ................................................................................ Technique or important point to remember when installing E E E (2). • Adding water, oil......................................................... Step in operation a ................................................................................ Point to remember when adding water or oil 5 ............................................................................ Quantity when filling with oil and water
2. General precautions when carrying out installation or removal (disassembly or assembly) of units are given together as PRECAUTION WHEN CARRYING OUT OPERATION, so be sure to follow these precautions when carrying out the operation. 3. Listing of special tools (1) For details of the description, part number, and quantity of any tools (A1, etc.) that appear in the operation procedure, see the SPECIAL TOOL LIST given in this manual.
30-2
PC78MR-6
DISASSEMBLY AND ASSEMBLY
PRECAUTIONS WHEN CARRYING OUT OPERATION
PRECAUTIONS WHEN CARRYING OUT OPERATION [When carrying out removal or installation (disassembly or assembly) of units, be sure to follow the general precautions given below when carrying out the operation.] 1. Precautions when carrying out removal work • • • • • • • • • •
If the coolant contains antifreeze, dispose of it correctly. After disconnecting hoses or tubes, cover them or fit blind plugs to prevent dirt or dust from entering. When draining oil, prepare a container of adequate size to catch the oil. Confirm the match marks showing the installed position, or make match marks in the necessary places before removal to prevent any mistake when assembling. To prevent any excessive force from being applied to the wiring, disconnect connectors by grasping the connector, not the wire. Tag wires and hoses to show their installed position to prevent any mistake when reinstalling. Check the number and thickness of the shims, and keep in a safe place. When raising components, be sure to use lifting equipment of ample strength. When using forcing screws to remove any components, tighten the forcing screws alternately. Before removing any unit, clean the surrounding area and fit a cover to prevent any dust or dirt from entering after removal.
a Precautions when handling piping during disassembling Fit the following blind plugs into the piping after disconnecting it during disassembly operations. 1) Face seal type hoses and tubes Nominal number
Plug (nut end)
Nut (elbow end)
02
07376-70210
02789-00210
03
07376-70315
02789-00315
04
07376-70422
02789-00422
05
07376-70522
02789-00522
06
07376-70628
02789-00628
2) Hoses and tubes using sleeve nuts Nominal number
Plug (nut end)
Sleeve nut (elbow end) Use the two items below as a set
02
07376-50210
07221-20210 (Nut), 07222-00210 (Plug)
03
07376-50315
07221-20315 (Nut), 07222-00312 (Plug)
04
07376-50422
07221-20422 (Nut), 07222-00414 (Plug)
05
07376-50522
07221-20522 (Nut), 07222-00515 (Plug)
06
07376-50628
07221-20628 (Nut), 07222-00616 (Plug)
10
07376-51034
07221-21034 (Nut), 07222-01018 (Plug)
12
07376-51234
07221-21234 (Nut), 07222-01219 (Plug)
3) Split flange type hoses and tubes Nominal number
Flange (hose end)
Sleeve head (tube end)
Split flange
04
07379-00400
07378-10400
07371-30400
05
07379-00500
07378-10500
07371-30500
PC78MR-6
30-3
DISASSEMBLY AND ASSEMBLY
PRECAUTIONS WHEN CARRYING OUT OPERATION
4) If the part is not under hydraulic pressure, the following corks can be used. Nominal number
Part Number
06
07049-00608
Dimensions D
d
L
6
5
8
08
07049-00811
8
6.5
11
10
07049-01012
10
8.5
12
12
07049-01215
12
10
15
14
07049-01418
14
11.5
18
16
07049-01620
16
13.5
20
18
07049-01822
18
15
22
20
07049-02025
20
17
25
22
07049-02228
22
18.5
28
24
07049-02430
24
20
30
27
07049-02734
27
22.5
34
30-4
PC78MR-6
DISASSEMBLY AND ASSEMBLY
2. • • • • • • • • • • • • •
PRECAUTIONS WHEN CARRYING OUT OPERATION
Precautions when carrying out installation work Tighten all bolts and nuts (sleeve nuts) to the specified (KES) torque. Install the hoses without twisting or interference. Replace all gaskets, O-rings, cotter pins, and lock plates with new parts. Bend the cotter pin or lock plate securely. When coating with adhesive, clean the part and remove all oil and grease, then coat the threaded portion with 2 - 3 drops of adhesive. When coating with gasket sealant, clean the surface and remove all oil and grease, check that there is no dirt or damage, then coat uniformly with gasket sealant. Clean all parts, and correct any damage, dents, burrs, or rust. Coat rotating parts and sliding parts with engine oil. When press fitting parts, coat the surface with anti-friction compound (LM-P). After fitting snap rings, check that the snap ring is fitted securely in the ring groove. When connecting wiring connectors, clean the connector to remove all oil, dirt, or water, then connect securely. When using eye bolts, check that there is no deformation or deterioration, screw them fully, and align the direction of the hook. When tightening split flanges, tighten uniformly in turn to prevent excessive tightening on one side.
3. Precautions when completing the operations • If the coolant has been drained, tighten the drain valve, and add water to the specified level. Run the engine to circulate the water through the system. Then check the coolant water level again. • If the hydraulic equipment has been removed and installed again, add hydraulic oil to the specified level. Run the engine to circulate the oil through the system. Then check the oil level again. • If the piping or hydraulic equipment, such as hydraulic cylinders, pumps, or motors, have been removed for repair, always bleed the air from the system after reassembling the parts. a For details, see TESTING AND ADJUSTING, Bleeding air. • Add the specified amount of grease (molybdenum disulphide grease) to the work equipment related parts. 4. Other precautions • To maintain the performance of the machine and to prevent failures, it is particularly important to pay attention to the degree of cleanliness of the oil in the hydraulic circuits. When adding oil or changing the oil, or when replacing the filters, check that the oil container and area around the filler of the hydraulic tank are clean. • To keep the hydraulic circuits clean and to protect the hydraulic equipment, be careful of the following points when disassembling or assembling. • Before disassembling, wash the machine. Be particularly careful to completely clean the area that is to be disassembled. • Do not let dirt or dust get into the hydraulic circuits when disassembling or assembling. • Carry out thorough flushing of the parts, and be particularly careful to do this thoroughly for the circuits of parts that have failed. • When disassembling or after flushing, always mask the openings of the piping or hydraulic equipment completely. • Do not use the seal tape for the thread of the plug mounts or connectors. • If any internal part of the hydraulic equipment breaks, disassemble and clean all the hydraulic equipment and circuits to remove any dirt or pieces from the circuit. If any parts of the hydraulic circuits are disassembled and assembled, also carry out thorough flushing of the hydraulic circuits. • When changing the oil in the hydraulic tank, or when removing the piston pump or piston pump piping, always bleed the air before starting the engine to prevent seizure of the pump. For details, see TESTING AND ADJUSTING, Bleeding air from piston pump.
PC78MR-6
30-5
DISASSEMBLY AND ASSEMBLY
PRECAUTIONS WHEN CARRYING OUT OPERATION
a After replacing or flushing the hydraulic tank oil, filter element, or strainer, or when removing and installing any hydraulic cylinder, hydraulic pump or any other hydraulic equipment or work equipment piping, always bleed the air as follows after completion of installation. 1. Run the engine at low idling, and extend and retract the steering, bucket, and lift arm cylinders 4 - 5 times without going to the end of this strike. (Stop approx. 100 mm before the end of the stroke.) 2. Operate the steering, bucket, and lift arm cylinders 3 - 4 times to the end of the stroke, then stop the engine and bleed the air from the plugs at the top of the hydraulic tank filter. 3. Raise the engine speed and repeat Step 2. to bleed the air. Repeat this procedure until no more air comes out from the plugs. 4. After completing bleeding the air, tighten the plugs 3 Plug: 11.3 ± 1.5 N·m {1.15 ± 0.15 kgm}
a If the engine is run at high speed from the start, or the cylinders are operated to the end of their stroke, the air inside the cylinder will cause damage to the piston packing. a After repair or long storage, follow the same procedure.
30-6
PC78MR-6
DISASSEMBLY AND ASSEMBLY
SPECIAL TOOL LIST
SPECIAL TOOL LIST
1
Burring of engine (For Model 102 engine)
Removal, installation of fuel injection pump assembly
t
1
Removal of drive gear (For Model 102 engine)
Removal, installation of noz- A zle holder assembly Removal, installation of cylinder head assembly Engine and main pump assembly
Puller
t
1
790-331-1110
Wrench
t
1
5
796-732-1311
Oil stopper
q
1
1
796T-226-1120
Push tool
q
1
790-101-3400
Bearing puller
q
1
790-101-3220
Screw
q
1
790-101-5201
Push tool kit
q
1
• 790-101-5281
• Plate
1
• 790-101-5221
• Grip
1
• 01010-51225
• Bolt
1
790-101-5201
Push tool kit
• 790-101-5331
• Plate
Part No.
Part Name
1
795-799-1130
Gear
2
795-799-1390 or 795-799-1210
Remover
3
795-799-1170
4
Puller
2
Stopping of hydraulic oil N
Q Removal, installation of spacer Removal of bearing outer race
Installation of oil seal
q
1 1
Press fitting of sub bearing outer race
4 • 790-101-5221 • Grip
1
• 01010-51225
• Bolt
1
790-101-5401
Push tool kit
• 790-101-5431
• Plate
1
• 790-101-5421
• Grip
1
• 01010-51240
• Bolt
1
6
796-765-1110
Push tool
t
1
N
fitting of main bearing Q Press inner race
7
792T-413-1120
Push tool
t
1
N
fitting of sub bearing inner Q Press race
796-730-2300
Wrench assembly
t
1
795-630-1803
Torque wrench
t
1
790-201-2770
Spacer
q
1
F
q
1 Press fitting of main bearing outer race
5
8
9
PC78MR-6
Nature of work, remarks
Pulling out of nozzle holder (For Model 102 engine) Tightening of cylinder head bolt (For Model 102 engine)
3
Disassembly, assembly of swing machinery assembly
Sketch
Q’ty
t
Symbol
New/ Remodel
Component
Necessity
a Tools with part number 79OT-OOO-OOOO cannot be supplied (they are items to be locally manufactured). a Necessity: t : Cannot be substituted, should always be installed (used). q : Very convenient if available, can be substituted with commercially available part. a New/remodel: N : Tools with new part numbers, newly developed for this model. R : Tools with upgraded part numbers, remodeled from items already available for other models. Blank : Tools already available for other models, used without any modification. a Tools marked Q in the Sketch column are tools introduced in special sketches (See SKETCHES OF SPECIAL TOOLS).
Measurement of running torque of shaft Installation of dust seal
30-7
1
Push tool kit
• 790-101-5141
• Plate
1
• 790-101-5021
• Grip
1
• 01010-50816
• Bolt
1
796-230-1110
Installer
t
1
790-101-5001
Push tool kit
q
1
• 790-101-5111
• Plate
1
• 790-101-5021
• Grip
1
• 01010-50816
• Bolt
1
4
796-230-1120
Installer
q
1
5
790T-230-1110
Push tool
q
1
791-685-8005
Compressor (B)
t
1
790-201-2860
Spacer
t
1
791-635-3160
Extension assembly
t
1
790-101-1600
Cylinder (686kN{70ton})
t
1
790-101-1102
Pump
t
1
791-616-1030
Remover and installer Cylinder (294kN{30ton})
t
1
t
1
790-101-1102
Pump
t
1
796T-267-1110
Push tool
t
1
790-201-2730
Spacer
t
1
790-101-2501
Push puller kit
q
1
• 790-101-2510
• Block
1
• 790-101-2520
• Screw
1
• 791-112-1180
• Nut
1
• 790-101-2540
• Washer
1
• 790-101-2630
• Leg
2
• 790-101-2570
• Washer
4
• 790-101-2560
• Nut
2
• 790-101-2650
• Adapter
2
L
Disassembly, assembly of carrier roller assembly
Disassembly, assembly of recoil spring assembly
M
Expansion, installation of track shoe assembly
R
Press fitting of input shaft oil seal of main pump
Installation of floating seal
Press fitting of bushing
790-105-1100
S
Disassembly, assembly of center swivel joint assembly
T
U
Nature of work, remarks
Press fitting of bushing
3
Disassembly, assembly of track roller assembly
Sketch
q
790-101-5001
2
30-8
Part Name
1
Disassembly, assembly of idler assembly
Disassembly, assembly of hydraulic cylinder assembly
Part No.
Q’ty
Symbol
New/ Remodel
Component
SPECIAL TOOL LIST
Necessity
DISASSEMBLY AND ASSEMBLY
N
Q Press fitting of cap
Compression of spring
Pulling out and press fitting of master pin
Press fitting of oil seal
790-502-1003
Cylinder repair stand
t
1
790-101-1102
Pump
t
1
1
Installation of floating seal
Separation of rotor and shaft
Disassembly, assembly of hydraulic cylinder
PC78MR-6
790-102-3802
Wrench assembly
t
1
790-330-1100
Wrench assembly
t
1
Boom, blade Removal, and boom swing installation of cylinder head Arm and bucket assembly
790-302-1340
Socket (Width across t flats: 80mm) Socket (Width across t flats: 70mm) Socket (Width across t flats: 60mm)
1
Boom and blade
1
Arm and boom swing
1
Bucket
Expansion of piston ring
Part No.
Part Name
2
3
790-102-1470 790-302-1290
4
790-720-1000
Expander
q
1
796-720-1670
Band
q
1
07280-01279
Clamp
q
1
796-720-1660
Band
q
1
07281-01159
Clamp
q
1
796-720-1650
Band
q
1
07281-01029
Clamp
q
1
796-720-1670
Band
q
1
07281-01279
Clamp
q
1
790-201-1702
Push tool kit
q
1
• 790-101-5021
• Grip
1
• 01010-50816
• Bolt
1
• 790-201-1811
• Push tool
1
790-201-1702
Push tool kit
• 790-101-5021
• Grip
1
• 01010-50816
• Bolt
1
• 790-201-1791
• Push tool
1
790-201-1702
Push tool kit
• 790-101-5021
• Grip
1
• 01010-50816
• Bolt
1
• 790-201-1771
• Push tool
1
790-201-1500
Push tool kit
• 790-201-1620
• Plate
1
• 790-101-5021
• Grip
1
• 01010-50816
• Bolt
1
790-201-1500
Push tool kit
• 790-201-1610
• Plate
5
Disassembly, assembly of hydraulic cylinder assembly
U
PC78MR-6
Nature of work, remarks
Removal, installation of piston nylon nut
Boom
Arm and boom swing Installation of piston ring Bucket
Blade
Boom and blade
q
1
6
7
Sketch
Q’ty
Symbol
New/ Remodel
Component
SPECIAL TOOL LIST
Necessity
DISASSEMBLY AND ASSEMBLY
q
Arm and boom swing
Press fitting of cylinder head bushing
1
Bucket
q
1
Boom and blade
q
1 1
Press fitting of cylinder head dust seal Arm and boom swing
30-9
Disassembly, assembly of hydraulic cylinder assembly
U
30-10
• Grip
1
• 01010-50816
• Bolt
1
790-201-1500
Push tool kit
• 790-201-1580
• Plate
1
• 790-101-5021
• Grip
1
• 01010-50816
• Bolt
1
790-441-1802
Remover
• 790-441-1810
• Sleeve
1
• 792-900-1530
• Screw
1
• 790-270-1110
• Adapter
1
• 01803-13034
• Nut
1
• 01643-33080
• Washer
1
790-101-4000
Puller (490kN{50ton}) t
1
790-101-1102
Pump
t
1
790-101-2102
Puller (294kN{30ton}) t
1
790-101-1102
Pump
t
1
790-201-2850
Spacer
t
1
791-535-1170
Plug
t
1
791-520-4140
Screw
t
1
790-101-2420
Adapter
t
1
790-101-2540
Washer
t
1
791-112-1180
Nut
t
1
790-101-2102
Puller (294kN{30ton}) t
1
790-101-1102
Pump
t
1
799-703-1200
Service tool kit
t
1
t
1
799-733-1120
Vacuum pump (220V) Vacuum pump (240V)
t
1
799-703-1400
Gas leak tester
t
1
1
2
V
Removal of arm cylinder assembly
Collection and reproduction of new Freon gas
3
799-703-1110 X
q
t
Sketch
Part Name
• 790-101-5021
7
Removal of work equipment and boom assembly
Removal of boom swing beacket
Part No.
Q’ty
Symbol
New/ Remodel
Component
SPECIAL TOOL LIST
Necessity
DISASSEMBLY AND ASSEMBLY
Nature of work, remarks
Arm and boom swing
1
Press fitting of cylinder head dust seal Bucket
1
Pulling out of boom foot pin
Pulling out of boom swing bracket pin
Pulling out of arm cylinder trunnion pin
Collection and supply of air conditioner gas
PC78MR-6
DISASSEMBLY AND ASSEMBLY
SPECIAL TOOL LIST
Note: Komatsu cannot accept any responsibility for special tools manufactured according to these drawings. F-1 Push tool
F-6 Push tool
PC78MR-6
30-11
DISASSEMBLY AND ASSEMBLY
SPECIAL TOOL LIST
F-7 Push tool
L-5 Push tool
30-12
PC78MR-6
DISASSEMBLY AND ASSEMBLY
COUNTERWEIGHT
COUNTERWEIGHT ASSEMBLY
8. Remove fuel filler mounting cover (9) of the fuel tank.
REMOVAL
9. Remove clamp (11) and float gauge hose (10). Loosen the clamp of the hose connected to the fuel filler tube on the back side of the fuel filler mounting cover, then remove the tube and cover together. a When removing the float gauge hose, check that the fuel level is below the connecting position of the hose.
a Stop the machine on a level place and set the upper structure in parallel with the track, then swing to the right about 20 degrees (since the mounting bolts are above the track) and lower the work equipment to the ground and stop the engine. 1. Remove cover (1) from the top of the hydraulic tank. 2. Remove engine cover (2). 3. Remove the bracket of damper case breather (3). 4. Remove 2 mounting bolts of air cleaner bracket (4) from the right front end of weight (5).
10. Using sling (1), hang weight (5) temporarily and remove the 3 weight mounting bolts. 11. Lift off weight assembly (5).
4 Counterweight assembly: 1,170 kg
[*1]
(With auxiliary weight)
5. Remove the bolt of air conditioner hose clamp. 6. Remove radiator support bracket (7) from the weight. 7. Remove air inlet cover (8) of the radiator, oil cooler, etc.
INSTALLATION
PC78MR-6
•
Carry out installation in the reverse order to removal.
[*1]
4 Weight mounting bolt: 1,150 – 1,1440 Nm {118 – 147 kgm}
30-13
DISASSEMBLY AND ASSEMBLY
INJECTION PUMP ASSEMBLY REMOVAL a Disconnect the wiring harness from the negative terminal of the battery. a Remove the counterweight. (See REMOVAL OF COUNTERWEIGHT.) 1. Remove the nut (1) of the engine stop solenoid rod and the nut of the accelerator cable (2) from the lever side of the pump, then remove the rod and cable assembly.
INJECTION PUMP
4. Remove the engine stop solenoid (8) and bracket together. 5. Remove the injection pipe clamp, and loosen the 4 sleeve nuts each on the pump side and nozzle side of the injection pipe (9), then remove the injection pipe (9). [*1] 6. Disconnect the inlet and outlet hoses (10) of the feed pump and lubrication tube (11). 7. Remove the rear bracket (12) of the pump.
[*2]
2. Disconnect the 3 terminals (PULL, HOLD, GND) (3) from the engine stop solenoid.
8. Remove the 6 bolts (14) used to install the pump holder (13) to the front cover (12).
3. Disconnect the connector (M19) (4) of the air conditioner compressor, water temperature sensor (M18) (5), glow plug (M17) (6) and harness clamp (7).
30-14
9. Remove the bolt (15) used to install the holder from the pump side, then remove the pump assembly and holder drive gear together. [*3] a When drive gear and idler gear are installed, their marks C must be matched to each other. Since those marks are not seen actually, however, mark match marks on the gear and pump in white paint when the pump is removed.
PC78MR-6
DISASSEMBLY AND ASSEMBLY
INJECTION PUMP
INSTALLATION •
Carry out installation in the reverse order to removal.
[*1]
3 Sleeve nut: 19.6 – 24.5 Nm {2 – 2.5 kgm}
[*2]
3 Outlet and inlet tube bolts of feed pump: 19.6 – 24.5 Nm {2 – 2.5 kgm}
[*3] 1. When installing holder (13) to pump (16), match the engraved lines (17) on them to each other. When installing the pump to the front cover, match the match marks made on the gear and pump when the pump was removed. Furthermore, match the engraved lines (18) of holder (13) and plate to each other and tighten the mounting bolts temporarily.
2. When the engraved line of 1.4TOP of the clamp is matched to the pointer, timing check holes (20) (the bolt hole on this side and the through hole under it) of tachometer removing opening (19) on front cover (12) must be matched to each other. Insert round bar about 100 mm long (21) in the holes to check that those holes are matched, then tighten each bolt to the specified torque.
PC78MR-6
30-15
DISASSEMBLY AND ASSEMBLY
CYLINDER HEAD
CYLINDER HEAD ASSEMBLY
8. Remove the air intake connector (6) between the turbocharger and the air intake manifold.
REMOVAL
k WARNING! Disconnect the battery (–) terminal in advance. 1. Remove the engine hood (See REMOVAL OF COUNTERWEIGHT). 2. Drain the coolant.
6 Coolant: 10.5 l
3. Remove the air intake hose (1) between the air cleaner and the turbocharger.
9. Disconnect the wiring harness connectors (M17) (7), (M18) (8) and (M19) (9). 10. Remove the guard (10). 11. Remove the filler pipe (11).
4. Remove the muffler protector (2). 5. Remove the 2 U-clamps (3).
[*1]
6. Remove the clamp (4) between the turbocharger and muffler, and then loosen the 4 mounting nuts of the turbocharger side of the exhaust pipe. [*2] 7. Remove the muffler (5).
30-16
PC78MR-6
DISASSEMBLY AND ASSEMBLY
12. Loosen the 2 mounting bolts of the air compressor and adjustment bolt, and remove the air compressor belt (12).
CYLINDER HEAD
17. Disconnect the blow-by hose (19). 18. Remove the fuel injection pipe clamp (20) and then remove the fuel injection pipes (21). [*3]
13. Disconnect the 3 hoses (13) from the fuel filter. 19. Disconnect the spill pipe (22). 14. Remove the air conditioner compressor (14), the bracket and the fuel filter together.
20. Remove the inspection cover of the turbocharger back side. 15. Disconnect the 3 terminals (PULL, HOLD, GND) (16) and linkage mounting nut (17) from the engine stop solenoid (15).
21. Disconnect the turbocharger lubrication tubes (23) and (24). [*4]
16. Remove the engine stop solenoid (15) and the bracket (18) together.
22. Remove the turbocharger and exhaust manifold assembly (25). [*5]
PC78MR-6
30-17
DISASSEMBLY AND ASSEMBLY
23. Remove the cylinder head cover (26).
CYLINDER HEAD
[*6]
29. Remove the 8 mounting bolts and the rocker arm (35), then remove the push rod. [*7] 30. Remove the lead (36) of the glow plug.
24. Loosen the 2 mounting bolts of the alternator (27) and remove the fan belt (28).
26. Disconnect the heater hoses (30) and (31).
31. Remove the 17 mounting bolts of the cylinder head (37), and lift off the cylinder head assembly. [*8]
27. Disconnect the radiator upper hose (32) and lower hose (33).
32. Remove the air intake manifold (38) from the cylinder head assembly.
25. Remove the fan (29).
28. Remove the water pump assembly (34).
30-18
PC78MR-6
DISASSEMBLY AND ASSEMBLY
INSTALLATION •
Carry out the installation in the reverse order to removal.
[*1]
3 U-clamp nut: 7.8 – 9.8 Nm {0.8 – 1.0 kgm}
[*2]
[*3] [*4] [*5] [*6]
[*7]
CYLINDER HEAD
a (1): Exhaust side, (2): Air intake side, (3): Front, (4): Rear
3 Mounting bolt of clamp between turbocharger and muffler: 1st time: 39.2 – 49 Nm {4 – 5 kgm} 2nd time:68.6 – 122.5 Nm {7 – 12.5 kgm} 3 Mounting nut of exhaust pipe turbocharger side: 27 – 34 Nm {2.8 – 3.5 kgm}
3 Fuel injection pipe sleeve nut: 19.6 – 24.5 Nm {2 – 2.5 kgm} 3 Joint bolt of turbocharger lubrication inlet tube: 9.8 – 12.7 Nm {1.0 – 1.3 kgm}
3 Mounting bolt of turbocharger and exhaust manifold: 34.3 – 53.9 Nm {3.5 – 5.5 kgm} a Insert the cylinder head cover O-ring in the O-ring groove, taking care not to expand or contact it, and fit it to cylinder head. Apply adhesive, if necessary. 3 Head cover mounting bolt: 7.84 – 9.8 Nm {0.8 – 1.0 kgm}
5) Mark marks (f) on the bolt heads and seats on the cylinder head in paint, then tighten the bolts in the order of [1] – [17] shown in figure until the angle between the mark of each bolt and the seat is 90° + 30° 0 . a After tightening the bolts, make 1 punch mark (g) on each bolt head. a If there are 5 or more punch marks on a bolt head, do not use that bolt again but replace it.
3 Rocker arm shaft mounting bolt : 19.6 – 29.4 Nm {2 – 3 kgm} 3 Rocker arm adjustment nut : 39.2 – 49 Nm {4 – 5 kgm}
[*8] 1. Tighten the cylinder head mounting bolts in the following order. 1) Apply molybdenum disulphide LM-P all over the threads and seating face of each bolt and the seats of the cylinder head holes. 2) Turn the bolts in the order of [1] – [17] shown in figure with the fingers until they are screwed in the holes of the cylinder head to 2 – 3 threads. 3) Tighten the bolts in the order of [1] – [17] shown in figure to the torque of 68.6}9.8 Nm {7}1 kgm}. 4) Tighten the bolts in the order of [1] – [17] shown in figure to the torque of 107.8}4.9 Nm {11}0.5 kgm}.
PC78MR-6
30-19
DISASSEMBLY AND ASSEMBLY
MAIN PUMP
MAIN PUMPASSEMBLY REMOVAL a Remove the engine hood and counterweight (See REMOVAL OF COUNTERWEIGHT). a Swing the upper structure from the parking position to the right by 30 degrees and lower the work equipment to the ground and stop the engine (so that the hydraulic oil will be drained easily).
k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank. 1. Remove air cleaner (1) and its bracket and air intake hose (2). 2. Remove oil splash protector (3) from the top of the pump and bottom plate (4) from the bottom of the pump. a Cover the manifold from which the air intake pipe is removed.
3. Remove drain plug (6) from the bottom of the suction tube of pump (5) to drain the oil.
5. Remove protector (9), joint (10), and 2 U-bolts (11) from muffler (8), then remove muffler (8) and bracket (12). [*1] (Since the engine mount is an obstacle to removal of the pump, remove the bracket.)
6. Remove the wiring harness connector of TVC solenoid (13). Remove 6 hoses (14) from the pump. [*2] a Mask the removed connector and fit male or female plugs to the hoses and nipple elbows.
4. Remove drain plug (7) from the PTO case to drain the oil. 6 Hydraulic oil: Approx. 80 l
6 PTO: 0.5 l
30-20
PC78MR-6
DISASSEMBLY AND ASSEMBLY
7. Lift pump (5) temporarily and remove suction tube (15) and pump mounting bolts, then remove pump (5). [*3] 4 Main pump assembly: 75 kg
CONTROL PUMP
CONTROL PUMP ASSEMBLY REMOVAL a Remove the counter weight (See REMOVAL OF COUNTER WEIGHT). 1. Remove the right side cover. 2. Remove hose (2) of control pump (1). 3. Remove the 4 mounting bolt and the control pump assembly (1). a Fit male or female plugs to the removed hoses and elbows.
INSTALLATION •
Carry out installation in the reverse order to removal. a When assembling, take care fully so that dirt, rust, flaw, etc. will not cause a trouble. [*1] 1. Tighten the mounting bolts of clamp (10) of the joint between exhaust muffler (8) and exhaust pipe to 39.2 – 49 Nm {4 – 5 kgm} first, then tighten to 68.6 – 122.5 Nm {7 – 12.5 kgm}. 2. Tighten the nuts of mounting U-bolts (11) of exhaust muffler (8) to 7.8 – 9.8 Nm {0.8 – 1.0 kgm}.
INSTALLATION •
Carry out installation in the reverse order to removal.
[*2] When installing the rubber hoses, be careful not to twist them. [*3] After supplying hydraulic oil and before starting the engine, bleed air from the main pump.
PC78MR-6
30-21
DISASSEMBLY AND ASSEMBLY
ENGINE AND MAIN PUMP ASSEMBLY
ENGINE AND MAIN PUMP
6. Remove the 2 bolts from the bottom of the engine to remove centralized wiring harness bracket (8) from the engine block.
REMOVAL a Remove the engine hood and counterweight (See REMOVAL OF COUNTERWEIGHT). a Swing the upper structure from the parking position to the right by 30 degrees and lower the work equipment to the ground and stop the engine (so that the hydraulic oil will be drained easily).
k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank. a Disconnect the cable from the negative (–) terminal of the battery. 1. Remove bottom plate (2) from the bottom of main pump (1) and drain plug (3) from the bottom of the suction tube to drain the hydraulic oil. 2. Loosen plug (4) of the remote hose to drain the cooling water from the radiator. a If the cooling water contains antifreeze, handle it as harmful liquid. Do not handle it illegally.
7. Remove the adjustment bolt of alternator (9). 8. Loosen the alternator mounting bolts through the hole of the partition and remove the V-belt. 9. Remove the mounting bolts to remove the alternator. (This work is required since the engine mount bolts cannot be removed.)
6 Hydraulic oil: 80 l
6 Cooling water: 8 l
10. Remove the wiring harnesses and connectors of air conditioner compressor (10), stop solenoid (11), TVC solenoid (12), water temperature gauge, glow plug, starting motor, etc.
3. Remove the covers from the boom foot, swing motor top, and inspection hole on the engine side. 4. Remove wiring harness (6) of alternator (5). 5. Remove the wiring harness of hydraulic switch (7) and the rotation sensor connector.
30-22
PC78MR-6
DISASSEMBLY AND ASSEMBLY
11. Remove guard (13) of air conditioner compressor (10) from the fan guard. 12. Remove the mounting bolt of the adjustment bolt and air conditioner compressor (10).
ENGINE AND MAIN PUMP
20. Remove protector (25) of exhaust muffler (24). Remove the clamp of the muffler and exhaust pipe to remove the muffler. Remove the exhaust pipe from the exhaust manifold. [*2]
13. Remove return hose (15) for the tank from fuel filter (14). 14. Remove the 2 mounting bolts and fuel filter (14). 15. Remove 2 heater hoses (16) from the valves on the thermostat side and engine block side.
21. Remove protector (26) of the pump hose. Remove the mounting bolts and suction tube (27) from the pump.
16. Loosen the clamps and disconnect upper hose (17) and lower hose (18) of the radiator from the engine. 17. Remove the 6 mounting bolts and fan (19). 18.Remove fuel hose (20) connected to the feed pump. Remove accelerator wire (21) from the governor lever. Loosen the locknut of bracket (22) and remove the wire. [*1]
22. Remove the 6 hoses (28) of pump (1). 23. Remove the 4 bolts of engine support (29). a Fit male or female plugs to the removed hoses and elbows.
19. Remove air cleaner (23), bracket, and air intake hose together from the air intake manifold.
PC78MR-6
30-23
DISASSEMBLY AND ASSEMBLY
24. Install the hook to engine assembly (30) and a sling to main pump (1) and lift off the engine and pump assembly, hanging it by 3 points.
ENGINE AND MAIN PUMP
INSTALLATION •
Carry out installation in the reverse order to removal.
[*1]
3 Fuel hose bolt: 19.6 – 24.5 Nm {2 – 2.5 kgm}
[*2] 1. Tighten the mounting bolts of the clamp of the joint between exhaust pipe and muffler to 39.2 – 49 Nm {4 – 5 kgm} first, then tighten to 68.6 – 122.5 Nm {7 – 12.5 kgm}. 2. Tighten the nuts of the mounting U-bolts of the muffler to 7.8 – 9.8 Nm {0.8 – 1.0 kgm}. [*3] After installing the engine mount to the revolving frame, apply clear lacquer to the unpainted engine mount fitting face. 3 Mounting bolt: 249 – 309 Nm {25 – 31.5 kgm}
2 Mounting bolt: Apply liquid adhesive LT-2
30-24
PC78MR-6
DISASSEMBLY AND ASSEMBLY
HYDRAULIC OIL COOLER ASSEMBLY REMOVAL a Remove the engine hood and counterweight (See REMOVAL OF COUNTERWEIGHT). 1. Disconnect the hose of reserve tank (1) from the radiator and remove it together with the tank bracket.
HYDRAULIC OIL COOLER, RADIATOR
RADIATOR ASSEMBLY REMOVAL a Remove the hydraulic oil cooler. For details, see REMOVAL OF HYDRAULIC OIL COOLER. [*1] 1. Move oil cooler (2) removed from radiator (1) to the left, without disconnecting the inlet and outlet hoses.
2. Remove receiver tank (2) from the frame. 3. Remove condenser (3) and arrange it and receiver tank so that they will not be obstacles. 4. Remove net (4) of the oil cooler.
2. Loosen remote plug (3) on the bottom of the radiator to drain the cooling water into a container. Remove protector (4) of the air conditioner compressor from fan guard (1). 6 Cooling water: Approx. 4 l
5. Remove the bottom plate of oil cooler (5) and prepare an oil receiving container, then remove cooler inlet hose (6) and outlet hose (7).
a If the cooling water contains antifreeze, handle it as harmful liquid. Do not handle it illegally.
6. Remove condenser bracket (8). Remove the 4 bolts used to secure the brackets on the top and bottom of the oil cooler, then remove the oil cooler.
INSTALLATION •
Carry out installation in the reverse order to removal.
PC78MR-6
30-25
DISASSEMBLY AND ASSEMBLY
3. Remove the 6 mounting bolts and fan (5). Loosen the clamps on the engine side and remove upper hose (6) and lower hose (7). [*2]
RADIATOR
INSTALLATION •
Carry out installation in the reverse order to removal.
[*1] When installing the radiator and oil cooler, check that the sealing material (sponge) between them is not deformed or broken but normal. [*2] 1. When inserting each hose, apply LG-6 to the adapter of the mating part. When tightening each clamp, check that it is not over the tube lock part. 3 Hose clamp: 8.8 Nm {0.9 kgm}
4. Remove the 2 bolts and bracket (8) installed to the partition under the operator's cab. Remove 2 mounting bolts (9) on the underside and radiator (1).
30-26
PC78MR-6
DISASSEMBLY AND ASSEMBLY
SWING MOTOR AND SWING MACHINERY ASSEMBLY
SWING MOTOR AND SWING MACHINERY
4. Remove the (9) swing machinery mounting bolts.
REMOVAL
5. Pull the plugs out of the forcing screw holes of the swing machinery and hang the body of the swing machinery with 2 slings wound onto it.
a Extend the work equipment to the maximum reach and lower it to the ground and stop the engine.
6. Using 2 forcing screws, disconnect the swing motor and swing machinery assembly (6) from the frame.
k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank.
7. Lift off swing motor and swing machinery assembly (6). [*1] 4 Swing motor and assembly: 77 kg
1. Remove the top cover of the swing motor
swing
machinery
2. Remove the level gauge bracket (7) and disconnect the hose (8). a Fit male or female plugs to the removed hoses and elbows.
INSTALLATION 3. Disconnect hoses (1), (2), (3), (4), and (5) of the swing motor. a Fit male or female plugs to the removed hoses and elbows. a Record the disconnected hoses to prevent a mistake in re-connecting them.
•
Carry out installation in the reverse order to removal.
[*1]
2 Contact faces on underside of swing machinery case and frame: Apply gasket sealant (LG-6)
3 Swing machinery case mounting bolt: 245 – 308.7 Nm {25 – 31.5 kgm} a When installing the assembly, take care not to break the drain tube of the swing machinery case. a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.
PC78MR-6
30-27
DISASSEMBLY AND ASSEMBLY
SWING MACHINERY
SWING MACHINERY ASSEMBLY
3) Disassemble No. 1 carrier assembly according to the following procedure. i) Remove snap ring (4), thrust washer (5), gear (6), bearing (7), and thrust washer (8).
DISASSEMBLY 1. Draining oil Remove the drain plug and drain the oil from the swing machinery. 6 Swing machinery case: Approx. 2 l
2. Swing motor assembly Remove swing motor assembly (1).
4) Drive in pin (9) to push out shaft (10). a After removing the shaft, remove pin (9). 5) Remove thrust washer (11) from carrier (12).
3. No. 1 sun gear and No. 1 carrier assembly 1) Remove No. 1 sun gear (2). 2) Remove No. 2 carrier (3).
30-28
PC78MR-6
DISASSEMBLY AND ASSEMBLY
4. No. 2 sun gear Remove No. 2 sun gear (13). 5. Ring gear Remove ring gear (14). 6. No. 2 carrier assembly 1) Remove No. 2 carrier assembly (15).
2) Disassemble No. 2 carrier assembly according to the following procedure. i) Remove snap ring (16), thrust washer (17), gear (18), bearing (19), and thrust washer (20). ii) Drive in pin (21) to push out shaft (22). a After removing the shaft, remove pin (21). iii) Remove thrust washer (23) from carrier (24).
SWING MACHINERY
7. Collar 1) Set the shaft and case assembly to a press and push sub bearing (25) with tool F1. a Operate the press slowly and push the bearing until the 2-piece collar can be removed. 2) Remove 2-piece collar (26).
8. Shaft assembly 1) Set block (1) to shaft and case assembly (27). Using push tool (2) and the press, remove shaft assembly (28). 2) Remove sub bearing (25).
3) Set the shaft assembly to the press. Using push tool (3), remove main bearing (29) and collar (30) from shaft (31).
PC78MR-6
30-29
DISASSEMBLY AND ASSEMBLY
9. Dust seal, oil seal, and bearing outer race 1) Remove dust seal (32) and oil seal (33) from case (34).
SWING MACHINERY
ASSEMBLY a Clean the all parts and check them for dirt or damage. Coat their sliding surfaces with engine oil before installing. 1. Oil seal Using tool F3, press fit oil seal (33) to case (34). a Replace the oil seal with new one. 3 Lip of oil seal: Grease (G2-LI)
3 Periphery of oil seal: Gasket sealant (LG-6)
2) Using tool F2, remove bearing outer races (35) and (36) from case (34).
2. Sub bearing outer race Using tool F4, press fit outer race (36) to case (34). a Press fitting force: Max. 8.82 kN {Max. 0.9 tons} 3. Main bearing outer race Using tool F5, press fit outer race (35) to case (34). a Press fitting force: Max. 19.6 kN {Max. 2.0 tons}
30-30
PC78MR-6
DISASSEMBLY AND ASSEMBLY
4. Shaft assembly 1) Install collar (30) to shaft (31). 2) Using tool F6 and the press, press fit main bearing (29). a Press fitting force: Max. 65.7 ~ 178.4 kN {Max. 6.7 ~18.2 tons}
3) Set case assembly (37) to shaft assembly (28). a Press fitting force: Max. 27.4 – 116.6 kN {Max. 2.8 – 11.9 tons} 4) Using tool F7 and the press, press fit sub bearing (25) until the 2-piece collar can be installed. a Press fitting force: Max. 27.4 – 116.6 kN {Max. 2.8 – 11.9 tons} a Turning the case, press fit the bearing slowly. 5) Install 2-piece collar (26).
PC78MR-6
SWING MACHINERY
6) Using tool (8) and the press, press fit shaft (31) until 2-piece collar (26) is secured. 7) Using tool F8, measure the running torque of the shaft. a Running torque: Max. 19.6 Nm {Max. 2.0 kgm}
5. Dust seal Using tool F9, press fit dust seal (32). a Replace the dust seal with new one.
30-31
DISASSEMBLY AND ASSEMBLY
6. No. 2 carrier assembly 1) Assemble No. 2 carrier assembly according to the following procedure. i) Install thrust washer (23) to carrier (24). ii) Match shaft (22) to the pin hole of the carrier and install it by hitting it lightly with a plastic hammer. iii) Insert pin (21). a After inserting the pin, bend the pin of the carrier. iv) Install thrust washer (20), bearing (19), gear (18), thrust washer (17), and snap ring (16).
SWING MACHINERY
9. No. 1 carrier assembly 1) Assemble No. 1 carrier assembly according to the following procedure. i) Install thrust washer (11) to carrier (12). ii) Match shaft (10) to the pin hole of the carrier and install it by hitting it lightly with a plastic hammer. iii) Insert pin (9). a After inserting the pin, bend the pin of the carrier.
iv) Install thrust washer (8), bearing (7), gear (6), thrust washer (5), and snap ring (4). 2) Install No. 2 carrier assembly (15) to the shaft and case assembly. 7. Ring gear Install ring gear (14).
2 Fitting face of ring gear: Gasket sealant (LG-6)
3 Ring gear mounting bolt: 58.5 – 73.5 Nm {6 – 7.5 kgm}
8. No. 2 sun gear Install No. 2 sun gear (13). a Take care not to install the sun gear and planetary gear upside down.
30-32
2) Install No. 1 carrier assembly (3). 3) Install No. 1 sun gear (2).
PC78MR-6
DISASSEMBLY AND ASSEMBLY
SWING MACHINERY
10. Swing motor assembly Install swing motor assembly (1).
3 Mounting bolt: 58.8 – 73.5 Nm {6 – 7.5 kgm}
2 Fitting face of motor: Gasket sealant (LG-6)
11. Supplying oil and grease Tighten the drain plug and supply engine oil through the oil filler. 6 Swing machinery case: Approx. 2 l
2 Swing machinery case (Main bearing): Grease (G2-LI), approx. 115 g a Apply LG-5 to the fitting part of the drain tube.
3 Drain plug: 44.1 – 93.1 Nm {4.5 – 9.5 kgm} a When mounting the assembly on the machine, apply gasket sealant LG-6 to the fitting face of the revolving frame.
PC78MR-6
30-33
DISASSEMBLY AND ASSEMBLY
SWING MOTOR ASSEMBLY REMOVAL a Remove the hoses of the swing motor. For details, see REMOVAL OF SWING MOTOR AND SWING MACHINERY ASSEMBLY. 1. Remove the 8 swing motor mounting bolts (1). 2. Remove the swing motor assembly. a After removing the swing motor, cover the swing machinery.
SWING MOTOR, CENTER SWIVEL JOINT
CENTER SWIVEL JOINT ASSEMBLY REMOVAL a Extend the work equipment to the maximum reach and lower it to the ground and stop the engine.
k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic tank. 1. Remove the top cover of the center swivel joint. 2. Remove travel drain hose (1) and swing motor hose (2). 3. Remove 5 hoses (3) of the control valve, travel forward/reverse, lateral hose, and 2nd travel speed selection from the top one. a Fit male or female plugs to the removed hoses, nipples, and elbows. a Record the disconnected hoses to prevent a mistake in re-connecting them.
INSTALLATION •
Carry out installation in the reverse order to removal.
a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.
30-34
PC78MR-6
DISASSEMBLY AND ASSEMBLY
CENTER SWIVEL JOINT
4. Remove the bottom plate of the center swivel.
INSTALLATION
5. Remove the 4 travel forward/reverse and lateral hoses, 2 2nd travel speed selection hoses, 2 drain hoses, etc. (4) from the underside of the swivel.
•
6. Remove the cotter pin of the lock pin of the center swivel from above, then pull out the lock pin and disconnect the lock plate.
Carry out installation in the reverse order to removal. a When installing the rubber hoses, be careful not to twist them. a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.
7. Hang the center swivel joint temporarily and remove the 4 mounting bolts from plate (5). a Fit male or female plugs to the removed hoses, nipples, and elbows and record the disconnected hoses to prevent a mistake in re-connecting them.
8. Lift off center swivel joint assembly (6).
4 Center swivel joint assembly: 18.5 kg
PC78MR-6
30-35
DISASSEMBLY AND ASSEMBLY
CENTER SWIVEL JOINT
DISASSEMBLY
ASSEMBLY
1. Remove cover (1).
1. Install slipper seal (7) and O-ring (6) to swivel shaft (5).
2. Remove snap ring (2). 3. Using tool T, pull swivel rotor (4) and ring (3) out of swivel shaft (5). 4. Remove O-ring (6) and slipper seal (7).
2. Set swivel shaft (5) to the block. Using the push tool, hit swivel rotor (4) with a plastic hammer lightly to install it. a Apply grease (G2-LI) to the contact surfaces of swivel shaft (5) and swivel rotor (4). a When installing the rotor, take care fully not to damage the lips of the slipper seal and oil seal. 3. Install ring (3) and secure it with snap ring (2). 4. Install the O-ring and cover (1).
3 Mounting bolt: 31.4 ± 2.94 Nm {3.2 ± 0.3 kgm} a When assembling, take care fully so that dirt, rust, flaw, etc. will not cause a trouble. a After assembling, seal each port with a polyethylene plug.
30-36
PC78MR-6
DISASSEMBLY AND ASSEMBLY
CONTROL VALVE ASSEMBLY REMOVAL
k Lower the work equipment to the ground and stop the engine, then loosen the oil filler cap gradually to release the residual pressure from the hydraulic tank.
CONTROL VALVE
7. Remove hoses (8) on the operator's cab side of the control valve in order from the top one. [*1] a Fit male or female plugs to the removed hoses and nipples.
a Disconnect the wiring harness from the negative (–) terminal of the battery. 1. Remove the top cover of the hydraulic tank. 2. Remove the right side cover. 3. Remove the tool box and the washer tank. 4. Remove 5 connectors (1) of the hydraulic switches and the wiring harness bracket.
8. Remove the 4 control valve mounting bolts from the underside of control valve stand (9) and lift off control valve assembly (10), using sling (1). 4 Control valve assembly: 65 kg
5. Remove each pilot hose (2). 6. Remove hoses (3) between the pump and merge-divider valve. a Mask the removed connectors.
INSTALLATION •
Carry out installation in the reverse order to removal.
[*1] 1. When assembling, take care fully so that dirt, rust, flaw, etc. will not cause a trouble. 2. When installing the rubber hoses, take care fully not to twist them. 3. Bleed all air from the swing PPC circuit. 4. After assembling, flush the all piping circuit. a The number of the control valves and pipes of a machine equipped with an attachment and those of Model UU are different from the above.
PC78MR-6
30-37
DISASSEMBLY AND ASSEMBLY
CONTROL VALVE
ASSEMBLY a When disassembling and assembling the precision parts of the hydraulic system, keep them clean extremely and work in a clean place. Take care fully not to hurt your fingers with the edges of the machines parts. a Check the fitting surfaces of the all parts. If a part has a scratch or a burr, replace it with new one since it can cause a trouble. Take care fully not to bruise or damage a part by dropping or hitting it. a Wash the all metallic parts in clean solvent and dry them with compressed air. If they are wiped with cloths or paper, fibers of the cloths and paper enter the product and contaminate the hydraulic system and can cause a trouble. Accordingly, never wipe the parts with cloths or paper. a When assembling, replace the consumable parts such as the O-rings and seals with new ones, as a rule. Apply a little amount of clean grease to the O-rings. a Take care of the installing direction of each spool. 1. When loosening or tightening mounting bolt (1) used to install the retainer of the spool return spring to each spool, be sure to put spool (2) in valve chest (3) (to prevent deformation of the spool). 3: 6.9 – 9.8 Nm {0.7 – 1.0 kgm}
3. When loosening or tightening plug (10) of spool (9) of bucket valve (8), be sure to put spool (9) in valve chest (8). 4. When loosening or tightening plugs (13) and (14) of spool (12) of arm valve (11), be sure to put spool (12) in valve chest (11). 5. When loosening or tightening plugs (17) and (18) of spool (16) of boom valve (15), be sure to put spool (16) in valve chest (15). a When tightening each of the orifices and plugs described above, apply 1 drop (approx. 0.02 g) of LOCTITE (No. 638) to it. Thoroughly degrease and dry the plug and the f e m a l e s c r e w o f t h e v a l v e c h e s t wi t h DRYSOL. Do not apply pressure to them for 2 hours after they are tightened. 3 Orifice and plug: 14.7 – 19.6 Nm {1.5 – 2.0 kgm}
2. When loosening or tightening orifice (5) and plug (6) of merge-divider valve (4), be sure to put spool (7) in valve chest (4) (to prevent deformation of the spool).
30-38
PC78MR-6
DISASSEMBLY AND ASSEMBLY
6. Tighten the combination bolts (1) and (2) in the order of (1) – (4) gradually in 3 times. 1) Combination bolt (1) tightening torque. 1st tightening torque: 19.6 – 29.4 Nm {2 – 3 kgm} 2nd tightening torque: 39.2 – 49.0 Nm {4 – 5 kgm} 3rd tightening torque: 58.8 – 73.5 Nm {6 – 7.5 kgm} 2) Combination bolt (2) tightening torque 29.4 – 34.3 Nm {3 – 3.5 kgm}
WORK EQUIPMENT PPC VALVE
WORK EQUIPMENT PPC VALVE ASSEMBLY ASSEMBLY a When assembling, clean and inspect the parts closely and take care fully so that dirt, rust, flaw, etc. will not cause a trouble. 1. When installing piston (1), apply grease (G2-LI) to its outside and the inside of the body hole. 2. When installing disc (2), adjust it so that the play of the lever end will be 0.5 ~ 3 mm (at 200 mm from the center of rotation of the lever).
a For the tightening torque of the auxiliary valves (Relief valve, suction safety valve, pressure compensation valve, etc.), see STRUCTURE AND OPERATION, MAINTENANCE STANDARD. a After assembling, seal each port with a nylon cap, etc. a When hanging the valve assembly, use eyebolts (04530-10815).
3. When installing joint (3) to body (4), apply LOCTITE as shown below. 1) When installing the joint, apply 1 drop (approx. 0.02 g) of LOCTITE (No. 262) each to 2 places of the female screw of the body. Bef or e i ns tall in g th e j oi nt, thor ou ghl y degrease and dry its male screw and the female screw of the body with DRYSOL. 2) Drop LOCTITE to the following positions. Female screw of body
4. Install spring (5) with its small diameter side on the shim (6) side. • Diameter of spring (Inside diameter) Small diameter side: 4.9, Large diameter side: 5.55 5. When installing plug (7) to body (4), take care that its tip will not enter the hole of the body 20 mm in diameter.
PC78MR-6
30-39
DISASSEMBLY AND ASSEMBLY
6. Apply grease (G2-LI) to the rocking part of joint (3) and the contact surfaces of disc (2) and piston (1). • Quantity of grease 1) Rocking part of joint: 2 – 4 cc/periphery 2) Contact surfaces of disc and piston: 0.3 – 0.8 cc/place 7. Seal the ports (P1 - P4, T, P) with nylon caps, etc. 8. Tighten each part to the following torque. • Joint (3): 39 – 49 Nm {4 – 5 kgm} • Bolt (8): 11.8 – 14.7 Nm {1.2 – 1.5 kgm} • Nut (9): 98 – 127 Nm {10 – 13 kgm} • Plug (10): 6 – 11 Nm {0.6 – 1.1 kgm}
TRAVEL PPC VALVE
TRAVEL PPC VALVE ASSEMBLY ASSEMBLY a When assembling, clean and inspect the parts closely and take care fully so that dirt, rust, flaw, etc. will not cause a trouble. 1. When installing piston (1), apply grease (G2-LI) to its outside and the inside of the body hole. 2. Install spring (2) with its small diameter side on the shim (3) side. • Diameter of spring (Inside diameter) Small diameter side: 4.9, Large diameter side: 5.55 3. Use the insertion jig to insert bushing (4). (Do not drive in the bushing with impact loads of a hammer, etc.) 4. Use the insertion jig to insert pin (5). (Do not drive in the pin with impact loads of a hammer, etc.) 5. Apply grease (G2-LI) to the rocking part of shaft (6) and the contact surfaces of lever (7) and piston (1) and the contact surfaces of plate (8) and pin of lever (9).
2 Quantity of grease (G2-LI) Rocking part of shaft:4 – 8 cc/periphery Contact surfaces of lever and piston: 0.3 – 0.8 cc/place Contact surfaces of plate and pin: 0.3 – 0.8 cc/place
6. Install washer (10) 1.6 mm thick first. If the difference between both sides at the stroke end of the lever exceeds 0.7°, change the washer thickness to reduce the difference to below 0.7°. (If the washer thickness is reduced by 0.3 mm, the stroke end angle is increased by 0.39°.) • Thickness of washer t: 1.0, 1.3, 1.6 7. After assembling, seal the ports (P1 – P4, T, P) with nylon caps, etc.
30-40
PC78MR-6
DISASSEMBLY AND ASSEMBLY
TRAVEL PPC VALVE
8. Tighten each part to the following torque. • Plug (11): 6 – 11 Nm {0.6 – 1.1 kgm} • Bolt (12): 3.9 – 4.9 Nm {0.4 – 0.5 kgm} (Apply LOCTITE #262.) • Screw (13): 7.8 – 9.8 Nm {0.8 – 1.0 kgm} • Plug (14): 4 – 9 Nm {0.4 – 0.9 kgm} • Bolt (15): 25 – 30 Nm {2.5 – 3.2 kgm} • Bolt (16): 27 – 34 Nm {2.8 – 3.5 kgm}
PC78MR-6
30-41
DISASSEMBLY AND ASSEMBLY
HYDRAULIC TANK ASSEMBLY REMOVAL a Swing the work equipment to a position at which the hydraulic oil can be drained easily and lower the work equipment to the ground.
HYDRAULIC TANK
6. Remove return hose (5), including the swing hose. 7. Remove hose (6) from the oil cooler and the other hoses. a Fit male or female plugs to the removed hoses, elbows, etc. a Record the disconnected hoses to prevent a mistake in re-connecting them.
k Stop the engine and loosen the hydraulic oil filler cap gradually to release the residual pressure from the hydraulic tank. 1. Drain the oil from the hydraulic tank. 2. Remove the top cover and right side cover of the hydraulic tank. 3. Remove the wiring harness clamp and washer tank (1). 4. Loosen the clamp and remove pump suction hose (2). 6 Hydraulic tank: 64 l
8. Using sling [1], remove the mounting bolts and lift off hydraulic tank assembly (7).
5. Disconnect the return hose (8).
INSTALLATION •
Carry out installation in the reverse order to removal. a When installing the rubber hoses, be careful not to twist them. a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.
30-42
PC78MR-6
DISASSEMBLY AND ASSEMBLY
FUEL TANK ASSEMBLY REMOVAL
FUEL TANK
7. Remove the inspection cover of fuel suction hose (7) and drain hose (8) from the underside of the revolving frame under the fuel tank, then remove the suction hose and drain hose.
a Disconnect the wiring harness from the negative terminal of the battery. a Drain the fuel through the drain valve. 6 When fuel tank is full: 125 l
1. Remove the front and left deck covers. 2. Remove the mounting bolts of fuel filler mounting cover (1) and loosen the hose clamp of the fuel filler tube and pull out the tube. 3. Remove the clamp and hose (2) of the fuel spill prevention gauge and take out cover (1). 4. Loosen the clamp of fuel supply hose (3) on the fuel tank (4) side and remove the hose from the tank.
8. Remove the 2 mounting bolts of fuel tank bracket (9) on this side from the underside of the revolving frame.
5. Remove the clamp of PPC hose (5) from the underside of the floor.
9. Remove the mounting bolt of the valve (10) and move them to the left side (to secure winder work space).
6. Remove the fuel sensor top cover of the floor and disconnect sensor connector (6).
10. Remove the nut and fuel tank band (11) on the deeper side from the tank. [*1]
PC78MR-6
30-43
DISASSEMBLY AND ASSEMBLY
11. Pull out fuel tank (4) and remove the clamp and tank air bleed hose (12), then remove the fuel tank.
CONTROLLER
CONTROLLER ASSEMBLY REMOVAL 1. Remove 4 bolt caps (2) of cover (1) at the rear of the operator's seat. 2. Remove the 4 bolts and cover (1).
INSTALLATION •
Carry out installation in the reverse order to removal.
3. Loosen the mounting bolts and remove connectors (4), (5), and (6) of controller (3).
[*1]
3 Nut of tank band: 5.9 ± 0.49 Nm {0.6 ± 0.05 kgm}
4. Remove the 4 mounting bolts and controller assembly (3).
INSTALLATION •
Carry out installation in the reverse order to removal. a Do not tighten the mounting bolts of connectors too strongly.
30-44
PC78MR-6
DISASSEMBLY AND ASSEMBLY
MONITOR PANEL ASSEMBLY REMOVAL 1. Pull cover (2) of monitor panel (1) and remove the claw stopper. 2. Remove side cover (3). 3. Remove the stopper of cover (4).
MONITOR PANEL, AIR CONDITIONER UNIT
AIR CONDITIONER UNIT ASSEMBLY REMOVAL a Disconnect the wiring harness from the negative terminal of the battery. a Connect a hose to the compressor charge unit and collect the refrigerant gas. (If the charge tool is available, this work becomes easy.) [*1] 1. Remove floor mat (1). 2. Remove dust covers (2) and (3). 3. Remove air conditioner unit cover (4).
4. Remove the 3 mounting bolts of monitor panel (1) and connectors (5) and (6) on the back side, then remove monitor panel assembly (1).
4. Remove duct (5) and the rear duct. 5. Remove cover (6) and the rear duct. 6. Remove 2 tubes (7) and push them in under the floor. [*2] a Fit male or female plugs to the removed tubes.
INSTALLATION •
Carry out installation in the reverse order to removal.
PC78MR-6
30-45
DISASSEMBLY AND ASSEMBLY
7. Loosen the clamp and remove heater hose (8) under the rear part of the operator's seat.
AIR CONDITIONER UNIT
11. Remove the 3 front mounting bolts and 3 rear ones and air conditioner unit assembly (12).
8. Remove 3 wiring harness connectors (9) for the air conditioner under the rear part of the operator's seat.
INSTALLATION 9. Remove 5 mounting bolts of operator's seat stand (10). 10. Raise the operator's seat stand to 60 mm above the floor by using 4 forcing screws (11) having screwing length of 70 - 80 mm, and the unit can be taken out. a If the operator's seat stand is raised too high, it will interfere with the wiring harnesses on both sides.
•
Carry out installation in the reverse order to removal.
[*1] 1. Connect the power cable for the compressor after charging the air conditioner with refrigerant gas (R134a). 2. Do not connect the outlet and inlet hoses of the receiver drier before the air conditioner is charged with refrigerant gas. 3. When assembling, take care that water (moisture), dirt, or air will not enter the air conditioner cycle. [*2] 1. When fitting the pipes, apply compressor oil (SNISO 5GS) to the flared parts and threaded parts. 2. Tighten the nuts on both ends of the refrigerant circuit hose to the following torque.
30-46
Size
Dimensions of thread
Width across flats
Tightening torque Nm {kgm}
# 08
16 x 1.5
19
11.8 – 14.7 {1.2 – 1.5}
# 11
20 x 1.5
24
19.6 – 24.5 {2.0 – 2.5}
# 14
22 x 1.5
27
29.4 – 34.3 {3.0 – 3.5}
PC78MR-6
DISASSEMBLY AND ASSEMBLY
OPERATOR’S CAB
OPERATOR’S CAB ASSEMBLY
7. Remove wiring harness connectors (6) and (7) of the radio system at the left rear and disconnect radio cable (8) from the jack.
REMOVAL
8. Remove connectors (9), (10), and (11) of the monitor panel at the right rear.
1. Remove the floor mat.
9. Remove the washer tank hose.
2. Remove air conditioner unit cover (1). 3. Remove rear cover (3) of monitor panel (2) and air conditioner duct.
10. Install a sling to the top of operator's cab assembly (12) and lift off the assembly. 4 Operator's cab assembly: 280 kg
4. Remove the mounting bolts used to install the operator's cab to the floor. 5. Remove the 4 nuts from the left front, rear, and right front and 1 bolt from the right rear of the operator's cab mount. 6. Remove the controller storage cover, wiring harness connectors of controller (4), and clamps (5).
INSTALLATION •
PC78MR-6
Carry out installation in the reverse order to removal.
30-47
DISASSEMBLY AND ASSEMBLY
FLOOR FRAME ASSEMBLY REMOVAL a Remove the operator's cab assembly. (See REMOVAL OF OPERATOR CAB.) a Disconnect the wiring harness from the negative terminal of the battery. a Connect a hose to the compressor charge unit and collect the refrigerant gas. (If the charge tool is available, this work becomes easy.) [*1]
FLOOR FRAME
7. Remove the 4 hoses connected to travel right and left control valves (9). 8. Remove the 2 hoses connected to the attachment control valve (10). 9. Disconnect the hoses connected to swing control valve and blade control valve.
1. Remove front deck cover (1) and left deck cover (2). 2. Remove 8 wiring harness connectors (3) of engine and pump control systems. 3. Remove 3 solenoid connectors (4) and cable clamp (5). 4. Remove the wiring harness connector of horn (6).
10. Loosen the clamps and remove 2 heater hoses (11). (At the rear of the operator's seat)
5. Remove 2 air conditioner gas tubes (7). (Fit male or female plugs to the removed tubes.)
11. Remove the 4 mounting bolts used to install the floor frame to floor mount (12). 6. Remove 8 hoses (8) of the work equipment control valve from the couplers.
12. Remove the accelerator wire from the injection pump and pull it out through the hole of the revolving frame to the floor side.
30-48
PC78MR-6
DISASSEMBLY AND ASSEMBLY
FLOOR FRAME
13. Install 4 eyebolts (1) to floor frame (13) and lift off the floor frame assembly. 4 Floor frame assembly: 200 kg
INSTALLATION • [*1]
Carry out installation in the reverse order to removal. a See INSTALLATION OF AIR CONDITIONER UNIT.
PC78MR-6
30-49
DISASSEMBLY AND ASSEMBLY
REVOLVING FRAME
REVOLVING FRAME ASSEMBLY
6. Remove receiver drier (5) and bracket together from the revolving frame and place them on their side.
REMOVAL a Disconnect the wiring harness from the negative terminal of the battery. a Remove the work equipment assembly. (See REMOVAL OF WORK EQUIPMENT ASSEMBLY.) a Remove the operator's cab assembly. (See REMOVAL OF OPERATOR'S CAB ASSEMBLY.) a Move the removed work equipment hoses to the chassis side. 1. Remove the engine hood. 2. Remove air cleaner assembly (1) and bracket hose together.
7. Remove the all mounting bolts used to install swing circle outer race (6) to the revolving frame.
3. Remove engine ventilator cover (2).
4. Hang boom cylinder assembly (3) temporarily and remove the hoses on the head side and bottom side. Pull out the mounting pin on the bottom side and lift off the cylinder assembly.
5. Remove fuel filler mounting cover (4).
8. Install a sling to the boom foot mounting unit and both sides of counterweight (7) and lift off the revolving frame assembly, hanging it by 3 points. a Use the hole of the revolving frame on the left rear side from which the receiver drier was removed.
INSTALLATION •
30-50
Carry out installation in the reverse order to removal. PC78MR-6
DISASSEMBLY AND ASSEMBLY
SWING CIRCLE
SWING CIRCLE ASSEMBLY
INSTALLATION
REMOVAL
•
Carry out installation in the reverse order to removal.
1. Remove the revolving frame assembly. For details, see REMOVAL OF REVOLVING FRAME ASSEMBLY.
[*1]
2 Threads of swing circle mounting bolt: Liquid adhesive (LT-2) 3 Swing circle mounting bolt: 245 – 309 Nm {25 – 31.5 kgm} Target: 279.5 Nm {28.5 kgm}
2. Hang swing circle assembly (1) temporarily and remove the 24 mounting bolts. [*1] 3. Remove swing circle assembly (1).
4 Swing circle assembly: 115 kg
[*2] [*2]
a Hang swing circle assembly (1) and install it to the track frame, directing mark S of the inner race to the just right s ide of the machine body as shown below.
2 Quantity of grease to be applied to circle: Apply sufficient quantity of grease (G2-LI).
PC78MR-6
30-51
DISASSEMBLY AND ASSEMBLY
WORK EQUIPMENT
WORK EQUIPMENT ASSEMBLY REMOVAL a Extend the work equipment to the maximum reach and lower it to the ground and stop the engine.
k Loosen the oil filler cap of the hydraulic tank gradually to release the residual pressure from the hydraulic 6tank. 1. Remove the top cover of the hydraulic tank. 2. Disconnect the working lamp connector (1), then disconnect the wiring harness (7) from the hose. 3. Remove the handrail (8). 4. Loosen the sleeve nut and disconnect the work equipment hose (2). [*1] a Move the removed hoses to the swing motor side. a Fit male or female plugs to the removed hoses and tubes. a Record the disconnected hoses to prevent a mistake in re-connecting them.
k Since an accumulator is not installed, loosen the sleeve nut of each hose gradually and check that oil will not spout out, then remove the hose.
7. Remove the lock plate (9) of the boom foot pin and handrail (10). 8. Lift the work equipment assembly (5) temporarily. 9. Pull out the boom hoot pin (6). [*3] a Check the quantity and positions of the inserted shims.
5. Remove the rod pin stopper used to lift boom cylinder (3) temporarily and pull out rod pin (4). [*2] 6. Lift off the boom cylinder (3) onto a stable stand of proper heght. a Check the quantity and positions of the inserted shims.
30-52
PC78MR-6
DISASSEMBLY AND ASSEMBLY
10. Lift off the work equipment assembly (5). a Check the quantity and positions of the inserted shims. 2 Work equipment assembly: 1,100kg
WORK EQUIPMENT
INSTALLATION •
Carry out installation in the reverse order to removal.
[*1] 1. Check that the O-rings are fitted to the sealing parts of each hose. 2. When installing the rubber hoses, take care not to twist them. [*2] 1. When assembling, apply GT2-T to the sliding surfaces of the pins. 2. Supply grease until it comes out through the dust seals on both sides of each bushing.
k When aligning the pin holes, never insert your fingers in the pin holes. a Adjust the shims so that the clearance between the cylinder rod head and bracket will be less than 1 mm.
[*3] 1. When assembling, apply GT2-T to the sliding surfaces of the pins. 2. Supply grease until it comes out through the dust seals on both sides of each bushing. 3. After supplying grease, change the position of the boom and supply grease further.
k When aligning the pin holes, never insert your fingers in the pin holes.
a Adjust the shims so that the clearance between the boom and bracket will be less than 1 mm. a Refilling with oil (Hydraulic tank) Run the engine to circulate the oil through the piping. Then, check the oil level again and add new oil to the specified level.
PC78MR-6
30-53
DISASSEMBLY AND ASSEMBLY
SWING BRACKET
SWING BRACKET ASSEMBLY REMOVAL 1. Remove the work equipment assembly (See REMOVAL OF WORK EQUIPMENT ASSEMBLY). 2. Disconnect the 2 boom cylinder hoses (1). [*1] a Fit male or female plugs to the removed hoses and elbows. 3. Lift the boom cylinder assembly (2), then pull out the bottom pin (3) and remove the boom cylinder assembly (2). [*2] a Check the quantity and positions of the inserted shims. 4 Boom cylinder assembly: 112kg
6. Remove the cover (6) and disconnect the connector (7). 7. Remove the bolt of the upper and lower brackets, then remove the potentiometer assembly (8). [*5] a After removing the potentiometer assembly, do not swing it around the lever or turn the lever unnecessarily.
8. Remove the work equipment hose clamp (9). [*4] a Make marks on the disconnected hoses so that you can connect them again in the original order.
4. Set the block under the swing cylinder, and remove the head pin (4). [*3] a Check the quantity and positions of the inserted shims. k Start the engine and retract the cylinder.
5. Remove the boom cylinder hose clamp (5). [*4]
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PC78MR-6
DISASSEMBLY AND ASSEMBLY
9. Lift the swing bracket (10) temporarily, and remove the mounting bolts of the swing pin upper side and lower side. a Plate (11) will be removed from the lower pin. 10. Pull out the pins (12) and (13) toward upper or lower. a If the pins are difficult to pull out, use puller V2. 11. Pull out the work equipment hoses and the boom cylinder hose, and remove the swing bracket assembly (10). [*6] a Check the quantity of the shims installed to the top of pin (13). 4 Swing bracket assembly: 234kg
SWING BRACKET
INSTALLATION •
Carry out the installation in the reverse order to removal.
[*1] 1. When installing, check that the O-ring is fitted to the sealing part of the hose. 2. When installing the rubber hoses, be careful not to twist them. [*2] [*3] 1) When assembling, apply G2-T to the sliding surface of the pins. 2) Use G2-T HYPER WHITE GREASE. 3) Adjust the shims so that the clearance between the cylinder and bracket will be 1 mm or less. k When aligning the pin holes, never insert your fingers in the pin holes.
[*4]
[*5]
a When installing the hoses, be careful not to twist them. a Referring to TROUBLESHOOTING, Procedure for correcting angle sensor, correct the sensor.
[*6] 1) When assembling, apply G2-T to the sliding surface of the pins. 2) Use G2-T HYPER WHITE GREASE. 3) Adjust the shims so that the clearance between the swing bracket and the bracket on the chassis side (the clearance on the upper side of the lower pin) will be 0.5 mm or less. a Shims of 3 thicknesses of 0.5, 1.0, and 2.0 mm are prepared. k When aligning the pin holes, never insert your fingers in the pin holes.
a After installing, check that the hydraulic oil level is normal. a After installing, check that the electric system works normally.
PC78MR-6
30-55
DISASSEMBLY AND ASSEMBLY
STEEL SHOE, RUBBER PAD SHOE, ROAD LINER
STEEL SHOE, RUBBER PAD SHOE, ROAD LINER ASSEMBLY
4. Remove tool R and move the machine forward so that the temporary pin will be in front of the idler and set block [1].
EXPANSION
5. Pull out the temporary pin and move the machine in reverse to expand track shoe (2).
1. Stop the machine so that the master pin will be between the idler and carrier roller and the track shoe can be expanded forward and backward. 2. Lower the work equipment to the ground and loosen lubricator (1) to lower the track shoe tension. [*1]
k Since the internal pressure of the adjustment cylinder is very high, do not loosen the lubricator more than 1 turn. If the grease does not come out easily, move the machine forward and in reverse.
INSTALLATION •
Carry out installation in the reverse order to removal.
[*1] a Adjust the tension of the steel shoe and road liner. For details, see TESTING AND ADJUSTING, Testing and adjusting track shoe tension.
3. Using tool R, pull out the master pin.
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PC78MR-6
DISASSEMBLY AND ASSEMBLY
RUBBER SHOE, FINAL DRIVE
RUBBER SHOE ASSEMBLY
FINAL DRIVE ASSEMBLY
REMOVAL
REMOVAL
1. Lower the work equipment to the ground and loosen lubricator (1) to lower the track shoe tension. [*1]
1. Expand the track shoe assembly. (See EXPANSION OF TRACK SHOE.)
k Since the internal pressure of the adjustment cylinder is very high, do not loosen the lubricator more than 1 turn. If the grease does not come out easily, move the machine forward and in reverse.
2. Swing the work equipment by 90 degrees and raise the machine body a little. 3. Put steel pipes in rubber shoe (2) and turn the sprocket in the reverse direction. If the rubber shoe is floated from the idler by the steel pipes, slide off the rubber shoe sideways.
2. Swing the work equipment by 90 degrees from the parking position and raise the machine body by pressing the work equipment against the ground and set block (1) between the track frame and track link to float sprocket (1) above the link tread.
k Lower the work equipment to the ground and stop the engine. Loosen the oil filler cap of the hydraulic tank to release the residual pressure from the hydraulic tank. 3. Remove travel motor side cover (2).
INSTALLATION •
Carry out installation in the reverse order to removal.
[*1] a Adjust the rubber shoe tension. For details, see TESTING AND ADJUSTING, Testing and adjusting track shoe tension. PC78MR-6
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DISASSEMBLY AND ASSEMBLY
4. Hang final drive assembly (3) temporarily.
IDLER
IDLER ASSEMBLY ASSEMBLY 1. Using tool L1, press fit bushings (9) and (10) to idler (4). a Press fitting force: 26 – 53 kN {2.6 – 5.4 tons}
5. Remove 4 travel motor hoses (4). 6. Remove 14 final drive assembly mounting bolts (5). [*1] 7. Lift off the final drive assembly. a Fit male or female plugs to the removed hoses and nipples.
INSTALLATION •
Carry out installation in the reverse order to removal.
[*1]
2 Final drive assembly mounting bolt: Liquid adhesive (LT-2)
2. Fit the O-ring and install support (7) to shaft (5) with dowel pin (8).
3. Using tool L2, install floating seal (6) to idler (4) and assembly of shaft (5) and support (7). a Apply oil to the sliding surface of the floating seal and take care that dirt will not stick to that surface.
a Bleed air from the travel motor. For details, see TESTING AND ADJUSTING, Bleeding air from each part. a Refilling with oil (Hydraulic tank) Add oil through the oil filler to the specified level. Run the engine to circulate the oil through the system. Then, check the oil level again.
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PC78MR-6
DISASSEMBLY AND ASSEMBLY
a When installing the floating seal, thoroughly clean, degrease, and dry the parts marked with the thick lines (the load ring and faces in contact with the load ring).
IDLER
4. Install the assembly of shaft (5) and support (7) to idler (4).
5. Supply oil between shaft (5) and idler (4). a When inserting the floating seal assembly in the housing, use the push jig. This push jig must push the load ring. [1]: Cylindrical push jig
6 Quantity of oil: 60 cc (EO-30CD)
a The metallic faces of the floating seal which are in contact with each other must be free from dirt. a After the floating seal is inserted, check that it does not slant more than 1 mm and its projection is as follows.
PC78MR-6
30-59
DISASSEMBLY AND ASSEMBLY
6. Using tool L2, install floating seal (3) to idler (4) and support (2). a Apply oil to the sliding surfaces of the floating seal and take care that dirt will not stick to the floating seal. a Degrease the contact faces of the floating seal and O-ring.
RECOIL SPRING
RECOIL SPRING ASSEMBLY DISASSEMBLY 1. Remove lubricator (1). 2. Remove yoke piston assembly (3) from recoil spring assembly (2). 3. Disassembly of recoil spring assembly 1) Remove set bolt (4).
2) Set recoil spring assembly (2) to tool M.
k Since the installing load of the spring is heavy and dangerous, set the spring securely. a Installing load of spring: 69.2 kN {7,061 kg} (Rubber shoe) 47.4 kN {4,837 kg} (Steel shoe)
7. Fit the O-ring and install support (2) with dowel pin (1).
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PC78MR-6
DISASSEMBLY AND ASSEMBLY
3) Apply hydraulic pressure slowly. After the spring is compressed, remove nut (5). a Compress the spring until the nut is loosened. a Release the hydraulic pressure slowly to eliminate the spring force. 4) Remove pilot (7) and cylinder (8) from spring (6). a Remove O-ring (13) from the cylinder.
RECOIL SPRING
3) Set recoil spring (2) to tool M.
4. Disassembly of yoke piston assembly 1) Remove wear ring (10) from yoke piston (9). 2) Remove snap ring (11) and U-packing (12). 4) Apply hydraulic pressure slowly to compress the spring. Tighten nut (5) so that the installing length of the spring will be a. a Installing length a of spring: 283 mm (Rubber shoe) 323 (Steel shoe) 2 Nut: Lubricant containing num disulphide (LM-P)
molybde-
ASSEMBLY 1. Assembly of yoke piston assembly 1) Fit U-packing (12) to yoke piston (9) and secure it with snap ring (11). 2) Install wear ring (10). 2. Assembly of recoil spring assembly 1) Fit O-ring (13) to cylinder (8). 2) Install cylinder (8) and pilot (7) to spring (6).
PC78MR-6
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DISASSEMBLY AND ASSEMBLY
5) Remove recoil spring assembly (2) from tool M. 6) Install set bolt (4). 3 : 58.8 – 73.5 Nm {6 – 7.5 kgm}
7) Fill cylinder (8) with grease (G2-LI). a Quantity of grease (G2-LI): Approx. 232 cc (Rubber shoe) Approx. 96 cc (Steel shoe) 8) Loosen lubricator (1) and insert yoke piston assembly (3) in recoil spring assembly (4) until grease comes out through part B.
TRACK ROLLER
TRACK ROLLER ASSEMBLY DISASSEMBLY 1. Remove pin (2) from track roller assembly (1), then remove collar (3).
3 Sliding parts of yoke piston and wear ring: Grease (G2-LI)
9) Tighten lubricator (1).
3: 58.8 – 88.2 Nm {6.0 – 9.0 kgm} a Install the valve so that the fitting will be on the outside. 2. Remove floating seal (4a) from collar (3). 3. Remove floating seal (4b) from roller (5).
4. Remove shaft and collar assembly (6) from roller (5).
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PC78MR-6
DISASSEMBLY AND ASSEMBLY
5. Remove floating seal (7a) from roller (5), then remove floating seal (7b) from shaft and collar assembly (6).
TRACK ROLLER
ASSEMBLY a When installing the floating seal, thoroughly clean, degrease, and dry the parts marked with the thick lines (the load ring and faces in contact with the load ring). Check that the contact surfaces of the floating seal are free from dirt.
6. Pull out pin (8) and remove collar (10) from shaft (9). 7. Remove the O-ring from shaft (9). 8. Remove bushings (11) and (12) from roller (5).
a When inserting the floating seal assembly in the housing, use the push jig. This push jig must push the load ring. [1]: Cylindrical push jig
a After the floating seal is inserted, check that it does not slant more than 1 mm and its projection is as follows.
PC78MR-6
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DISASSEMBLY AND ASSEMBLY
a The metallic faces of the floating seal which are in contact with each other must be free from dirt. a Supply GO140 oil. Quantity of oil: 210 – 230 cc a Thoroughly clean the parts to be in contact with the supplied oil. After cleaning them, the dirt remaining on these parts of 1 roller assembly must be below 25 mg and the size of the dirt must be below 0.3. a Set plug (2) on the outside of the machine body.
TRACK ROLLER
3. Using tool L4, press fit floating seal (7b) to shaft (9). 4. Using tool L4, press fit floating seal (7a) to roller (5). a Press fit floating seal (4b) similarly.
5. Install shaft and collar assembly (6) to roller (5). 6. Turn over the assembly of roller (5) and shaft (6). 1. Using tool L3, press fit bushing (12) to roller (5). a Press fit bushing (11) similarly. 2. Fit the O-ring to shaft (9), then install collar (10) and pin (8) to shaft (9).
7. Using tool L4, install floating seal (4a) to collar (3).
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PC78MR-6
DISASSEMBLY AND ASSEMBLY
8. Install collar (3) to shaft (9), then install pin (2). 9. Fill the roller with oil and tighten plug (13). 5 Track roller: 210 – 230 cc (GO-140)
HYDRAULIC CYLINDER
HYDRAULIC CYLINDER ASSEMBLY DISASSEMBLY 1. Cylinder assembly 1) Set cylinder assembly (1) to tool U1. 2) Using a hydraulic pump or a power wrench and tool U2, loosen head assembly (2).
3) Pull out piston rod assembly (3). a Place an oil pan, etc. under the cylinder to receive the oil.
PC78MR-6
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DISASSEMBLY AND ASSEMBLY
HYDRAULIC CYLINDER
2. Piston rod assembly 1) Set piston rod assembly (3) to tool U1. 2) Using a hydraulic pump or a power wrench and tool U3, remove nylon nut (4). a Width across flats of nut: Cylinder Boom Width across 80 flats
Arm
Bucket
Swing
Blade
75
60
70
75
3. Disassembly of piston assembly 1) Remove wear ring (9). 2) Remove piston ring (10). a Apply a screwdriver, etc. to the piston ring and hit it with a hammer to break off the piston ring.
3) Remove piston assembly (6) from piston rod (5). 4) Remove head assembly (2).
5) Remove cap (6) and take out 9 balls (7), then remove plunger (8). • Perform this work for only arm cylinder.
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4. Disassembly of cylinder head assembly 1) Remove the O-ring and backup ring (11). 2) Remove O-ring (12). 3) Remove snap ring (13) and dust seal (14). 4) Remove rod packing (15). 5) Remove bushing (16).
PC78MR-6
DISASSEMBLY AND ASSEMBLY
ASSEMBLY a Apply engine oil to the sliding surfaces of each part and take care not to damage the packing, dust seals, O-rings, etc. a Do not insert the backup ring forcibly. Heat it in water at 50 - 60°C, then insert it carefully.
HYDRAULIC CYLINDER
2. Assembly of piston assembly 1) Using tool U4, expand piston ring (10). a Set the piston ring to tool U4 and revolve the handle by 8 - 10 turns to expand the piston ring. 2) Using tool U5, contract piston ring (10).
1. Assembly of cylinder head assembly 1) Using tool U6, press fit bushing (16). 2) Install rod packing (15). 3) Using tool U7, install dust seal (14) and secure it with snap ring (13). 4) Fit O-ring (12). 5) Fit the backup ring and O-ring (11).
3) Install wear ring (9). a Take care not to open the closed gap of the ring too much.
PC78MR-6
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DISASSEMBLY AND ASSEMBLY
HYDRAULIC CYLINDER
5. Piston rod assembly 1) Set plunger (8) to the piston rod and install 9 balls (7) and secure them with cap (6). a Check that there is some play at the plunger tip. • Perform this work for only arm cylinder.
6. Cylinder assembly 1) Set the cylinder to tool U1. 2) Install piston rod assembly (3). a Push in the piston rod to the end. 2) Install head assembly (2) to piston rod (5). 3) Install piston assembly (6) to piston rod (5).
3) Using a hydraulic pump or a power wrench and tool U2, tighten head assembly (2). 4) Set piston rod assembly (3) to tool U1. 5) Using tool U3, tighten nylon nut (4).
2 Nylon nut: Liquid adhesive (Equivalent to LOCTITE 262)
3 Nylon nut: Cylinder name Boom Arm Bucket Blade Swing
3 Head addembly: Cylinder name
Boom Arm
Tightening torque 3.97 ± 0.4 kNm 4.12 ± 0.41 kNm 2.16 ± 0.22 kNm 3.14 ± 0.31 kNm 2.6 ± 0.26 kNm
{405 ± 40.5 kgm} {420 ± 42.0 kgm} {220 ± 22 kgm} {320 ± 32.0 kgm} {265 ± 26.5kgm}
Bucket
Blade Swing
Tightening torque 980 ± 98 Nm{100 ± 10 kgm} 1,107 ± 110 Nm {113 ± 42.0 kgm} 1st time: Tighten to 1,176 – 1,372 Nm {120 – 140 kgm}. 2nd time: Loosen to 0 Nm {0 kgm}. 3rd time: Tighten to 392 Nm {40 kgm} 4th time: Apply angle tightening (Tighten periphery of cylinder head by 3.5 – 4.5 mm). 1.03 ± 0.10 Nm {105 ± 10.5 kgm} 981 ± 98.1 Nm {100 ± 10 kgm}
a After assembling, clean each part and mask the piping ports and pin hole
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PC78MR-6
90 OTHERS Hydraulic circuit diagram (For STD spec.) ............... 90- 3 Hydraulic circuit diagram (For EU spec.) .................. 90- 5 Electrical circuit diagram (For STD spec.) (1/2) ........ 90- 7 Electrical circuit diagram (For STD spec.) (2/2) ........ 90- 9 Electrical circuit diagram (For EU spec.) (1/2)........... 90-11 Electrical circuit diagram (For EU spec.) (2/2)........... 90-13
PC78MR-6
90-1 (1)
HYDRAULIC CIRCUIT DIAGRAM (FOR STD SPEC.)
PC78MR-6
90-3 (1)
HYDRAULIC CIRCUIT DIAGRAM (FOR EU SPEC.)
PC78MR-6
90-5 (1)
ELECTRICAL CIRCUIT DIAGRAM (FOR STD SPEC.) (1/2)
PC78MR-6
90-7 (1)
ELECTRICAL CIRCUIT DIAGRAM (FOR STD SPEC.) (2/2)
PC78MR-6
90-9 (1)
ELECTRICAL CIRCUIT DIAGRAM (FOR EU SPEC.) (1/2)
PC78MR-6
90-11 (1)
ELECTRICAL CIRCUIT DIAGRAM (FOR EU SPEC.) (2/2)
PC78MR-6
90-13 (1)
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