Cargador 920 & 930 Sistema Hidraulico

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REG00523-04 December 1979

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920, 930, 930T & 930T Series II

Wheel Loader Hydraulic System

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920

930, 930T & 930T SERIES II

930

41 J1-UP 75J1 UP 62K1-UP M

71 H1-UP 79J1-UP 41K1-UP 73U1-UP

1781-UP

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INTRODUCTION

This pUblication has instructions and procedures for the subject on the front cover. The information, specifications, and illustrations in this publication are on the basis of information that was current at the time this issue was written. Correct operation, maintenance, test and repair procedures will give this product a long service life. Before starting a test, repair or rebuild job, the serviceman must read the respective sections of the Service Manual, and know all the components he will work on. Your safety, and the safety of others, is at all times very important. When you see this symbol or this symbol in the manual, you must know that caution is needed for the procedure next to it. The symbols are warnings. To work safely, you must understand the job you do. Read all instructions to know what is safe and what is not safe. .._"

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It is very important to know the weight of parts. Do not lift heavy parts by hand. Use a hoist. Make sure heavy parts have a good stability on the ground. A sudden fall can cause an accident. When lifting part of a machine, make sure the machine has blocks at front and rear. Never let the machine hang on a hoist, put blocks or stands under the weight. When using a hoist, follow the recommendation in the manual. Use correct lift tools as shown in illustrations to get the correct balance of the component you lift. This makes your work safer at all times. 40400X3

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SYSTEMS OPERATION ", Loader Hydraulic System..................................................... Lift Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . . . . . .. Lift Kickout . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Main Pressure Relief Valve ....................................•... , ... ..... Tilt Circuit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .. Bucket Position Indicator and Bucket Positioner.. .. .. .. ..... .. .. ... .. .. .. .. Tilt Circuit Relief Valves..................................................

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4 7 7 5 6 6 6

TESTING AND ADJUSTING

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Loader Hydraulic System Bucket Position Indicator and Positioner Bucket Position Indicator Bucket Positioner Checking Pump Efficiency Control Lever Effort Lift Kickout Loader System Test Procedures Lift Circui t Drift Lift and Tilt Circuit Speeds.................................. Multi-Purpose Bucket Circuit Tilt Circuit Drift Main Pressure Relief Valve and Tilt Circuit Relief Valves Main Pressure Relief Valve Tilt Circuit Relief Valve (Head Ends) Tilt Circuit Relief Valve (Rod Ends) Operational Checks Visual Checks

8 14 14 14 " 9 15 13 ,.' .. 9 10 9 11 10 11 11 12 13 9 8

SPECIFICATIONS

NOTE: For Specifications with illustrations, make reference to the SPECI­ FICATIONS FOR 920 and 930 WHEEL LOADER HYDRAULIC SYS­ TEM, Form No. REG01271. If the Specifications given in Form REGOl271 are not the same as given in the Systems Operation and the Testing and Adjusting, look at the printing date on the back cover of each book. Use the Specifications given in the book with the latest date.

NOTE: The "C" is an indication of a change from the former issue.

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3

920 & 930 LOADER HYDRAULIC SYSTEM

SYSTEMS OPERATION

LOADER HYDRAULIC SYSTEM

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10~11

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PUMP FL.GW

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BLOCK~O OIL

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SUPPLY OIL

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LOADER HYDRAULIC SYSTEM IN HOLD POSITION 1. Filter. 2. Lift and tilt control valve body. 3. Tilt circuit port (connects to rod ends of tilt cylinders). 4. Lift circuit port (connects to rod ends of lift cylinders) . 5. Make-up valve housing.

6. Lift circuit make-up valve (rod ends). 7. Lift circuit check valve. 8. Lift circuit control valve spool. 9. Tilt circuit control valve spool. 10, Tilt circuit port (connects to head ends of tilt cylinders).

The loader hydraulic system consists of a pump, a hydraulic oil supply tank, the lift and tilt control valve with attached make-up and relief valves, control linkage, and the lift and tilt cylinders. The lift circuit consists of a check valve, valve spool and make-up valves. When moved to an operating position, the valve spool directs pump flow to the lift cylinders. The spool has four posi­ tions: RAISE, HOLD, LOWER and FLOAT. The tilt circuit consists of a check valve, valve spool, rod end and head end relief valves and make­ up valves. When moved to an operating position, the valve spool directs pump flow to the tilt cylin­ ders. The spool has three positions: TILT BACK, HOLD and DUMP. The lift system includes a hydraulic lift kick out circuit. The mechanism in this circuit consists of a master cylinder mounted on the loader frame near the hydraulic lift cylinder and a slave cylin­ der on the left side of the hydraulic tank to move the lift control lever linkage. When the lift arms

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11. Lift circuit port (connects to head ends of lift cylinders). 12. Tilt circuit check valve. 13. Port (connects to pump). 14. Port (blocked). 15. Lift circuit make-up valve (head ends). 16. Tilt circuit make-u p valve (rod ends). 17. Tilt cylinders (two).

18. Lift cylinders (two). 19. Tilt circuit relief valve

(rod en~s).

20. Tilt circuit relief valve (head ends). 21. Tilt circuit make-up valve (head ends).

22. Oil supply tank.

23. Main pressure relief

valve. 24. Pump.

reach the preset lift height the master cylinder actuates the slave cylinder, which automatically moves the lift control lever (and the lift spool in the control valve in the hydraulic tank) from the RAISE position detent to the HOLD position. The tilt system includes either a bucket position indica tor or a bucket positioner hydraulic circuit. The mechanism in this circuit consists of a master cylinder mounted on the right hydraulic tilt cyl­ inder and a slave cylinder on the left side of the hydraulic tank to move the tilt control lever link­ age. The master cylinder actuates the slave cyl­ inder, which automatically moves the tilt control lever (and the tilt spool in the control valve in the hydraulic tank) from the TILT BACK position detent to the HOLD position at a preset bucket digging angle. Oil flow for the hydraulic system is supplied by the large section of a two section insert vane-type hydraulic pump. The oil flow through the hydraulic system when

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. the control levers are in HOLD position is as follows: The pump draws supply oil from the tank. The oil is directed to the lift and tilt control valve in the tank and flows by the tilt and lift valve spools. The valve spools are held in HOLD position by centering springs. The oil leaves the lift and tilt control valve and flows to the tank. On machines equipped with an implement control valve, the oil flows through the implement valve before flo'Ning to the tank.

MAIN PRESSURE RELIEF VALVE (5J9113)

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ference between these pressures becomes sufficient to overcome the force of spring (3), the dump valve (5) is unseated. Pump flow is directed through port (12) to the tank, preventing any further rise in pressure.

MAIN PRESSURE RELIEF VALVE (3G2315)

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The 3G2315 main pressure relief valve is mounted to the control valve body. The valve limits the pressure that can be imposed on the hydraulic pump. It also protects both the lift and tilt circuits in all operating positions except DUMP position. This valve consists of a spring­ loaded dump valve and a spring-loaded pilot valve.

The main pressure relief valve is mounted to the control valve body. The valve limits the pressure that can be imposed on the hydraulic pump. It also protects both the lift and tilt circuits in all opera­ ting positions. This valve consists of a spring­ loaded dump valve and a spring-loaded pilot valve.

6 7 10

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MAIN PRESSURE RELIEF VALVE

1. Adjustment screw.

8

9

10

2. Orifice. 3. Dump v81ve spring. 4. Dump valve. 5. Dump ports. 6. Pilot valve spring. 7. Pilot valve. 8. Chamber. 9. Orifice. 10. Inlet chamber. .93219

MAIN PRESSURE RELIEF VALVE

1. Shims. 2. Pilot valve spring. 3. Dump valve spring. 4. Orifice. 5. Dump valve. 6. Dump valve seat. 7. In­ let chamber. 8. Pilot valve. 9. Pilot valve seat. 10. Orifice. 11. Chamber. 12. Dump port.

When the pilot valve (8) is seated, the pressure in chambers (7) and (11) is equal. Dump valve (5) is held seated by spring (11). The pressure at which the dwnp valve opens is determined by the shim­ adjusted force of spring (2) and force of spring (3). As the system pressure approaches the relief valve setting, the pilot valve is unseated slightly opening orifice (0) to tank. Orifice (10) is larger than orifice (4). Therefore, as the pilot valve moves against the spring force, more area of orifice (10) is exposed. When the exposed area becomes larger than the area of orifice (4), oil can leave chamber (11) faster, than the oil can enter chamber (11). The pressure in chamber (11), at this point, is lower than pressure in chamber (7). When the dif­

When the pilot valve (7) is seated, the pressure in chamber (8) and inlet chamber (10) is equal. Dump valve (4) is held seated hy dump valve spring (3). The pressure at which the dump valve opens is determined by the shim adjusted force of pilot valve spring (6) and force of dump valve spring (3). As the system pressure approaches the relief valve setting, the pilot valve is unseated slightly opening orifice (2) to tank. Orifice (2) is larger than orifice (9). Therefore, as the pilot valve moves against the spring force, more area of orifice (2) is exposed. When the exposed area be­ comes larger than the area of orifice (9), oil can leave chamber (8) faster, than the oil can enter it. The pressure in chamber (8), at this point, is lower than pressure in inlet chamber (10). When the difference between these pressures becomes sufficient to overcome the force of spring (3), the dump valve (4) is unseated. Pump flow is directed through ports (5) to the tank, preventing any further rise in pressure.

5

SYSTEMS OPERATION

920 & 930 LOADER HYDRAULIC SYSTEM

TILT CIRCUIT When the tilt control lever is moved to TILT BACK position, the tilt control valve spool moves outward. Pump flow is directed to the tilt circuit check valve. The check valve remains seated until pump flow pressure becomes greater than the com­ bined force of the oil pressure in the head ends of the cylinders and the force of the check valve return spring. The check valve prevents reverse oil flow and resulting cylinder drift. The oil unseats the check valve and is directed to the head ends of the tilt cylinders, tilting the bucket back. Oil in the rod ends of the cylinders returns through the control valve to the supply oil in the tank. When the control lever is moved to DUMP posi­ tion, the valve spool is moved into the valve body and the oil flow is reversed. Oil is directed to the rod ends of the tilt cylinders, dumping the bucket. Oil from the head ends of the cylinders returns to the supply oil in the tank. The tilt circuit make-up valve housing is mounted to the lift and tilt control valve body. The make-up valves will unseat and allow oil from the tank to supplement pump flow when the piston rods extend or retract faster than the pump can supply oil to the cylinders. A make-up valve will also unseat when the tilt circuit is in HOLD position and the tilt cylinder piston rods are moved by an excessive force being exerted on the bucket. In this case, a tilt circuit relief valve will open to relieve oil pressure and a make-up valve will unseat to fill the void of oil in the opposite ends of the cylinders. Tilt Circuit Relief Valves When the tilt circuit control valve spool is in HOLD position, the tilt relief valves (rod ends) and (head ends) protect the circuit and machine components by limiting the external force that can be imposed on the bucket. The tilt relief valves have higher settings than the main pressure relief valve. All relief valves are mounted to the tilt circuit make-up valve housing. The tilt relief valves are spring-loaded dump valves. When oil pressure exceeds the tilt relief valve settings, the springs are compressed and the dump valves open to the dump ports. The oil flows through the dump ports and returns to the tank. The relief valves in the tilt circuit allow excessive external forces on the bucket to move the tilt cylinder pistons, thus preventing damage to the machine components. Bucket Position Indicator and Bucket Positioner The bucket position indicator (1) is a strip, mounted on a tube which moves with the hydraulic cylinder rod end, and an angle, mounted on the hydraulic cylinder. As the bucket is moved to TILT BACK position the strip and angle become visually aligned. When they are aligned the bucket

BUCKET POSITION INDICATOR AND

POSITIONER ACTUATOR

1. Bucket POSitIon indicators. 2. Bucket positioner master cylinder. 3. Cam, mounted on a tube connected to the rod end of the hydraulic cylinder. 4. Roller.

is at the correct digging angle and the tilt control lever is moved to the HOLD position to stop the bucket in the digging position.

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8 BUCKET POSITION INDICATOR AND

POSITIONER SYSTEM

1. Bucket position indicators. 2. Bucket pOSitioner master cylinder. 4. Roller. 5. Hydraulic tank. 6. Right side hydraulic tilt cylinder. 7. Bucket position slave cylinder. 8. Hydraulic tube (connects master cylinder to slave cylinder). 9. Tube assembly.

On machines equipped with the hydraulic bucket positioner, the bucket positioner automatically moves the tilt control lever from TILT BACK to HOLD position. This action stops the bucket movement at the conect digging position. With the tilt control lever in TILT BACK posi­ tion, the tilt cylinder rod extends to a position where cam (3) moves under roller (4) and the roller actuates the piston in the bucket positioner master cylinder (2). The master cylinder hydraulic­ ally actuates the bucket positioner slave cylinder (7). The action of the slave cylinder moves the tilt control lever and the spool in the control valve to the HOLD position. The tilt control lever must be held in the TILT BACK position to allow the hydraulic cylinder rod to move the bucket from the preset digging angle to full tilt back.

The location of cam (3) sets the bucket tioner for the desired bucket digging angle.

POSl­

LIFT CIRCUIT When the lift control lever is moved to RAISE position, the lift circuit control valve spool is moved outward. The oil pressure opens the lift circuit check valve and pressure oil is directed to the head ends of the lift cylinders, raising the lift ann. Oil in the rod ends of the lift cylinders returns back through the control valve and to the tank. When the control lever is moved to LOWER position, the valve spool is moved into the valve body and pressure oil is directed to the rod ends of the lift cylinders. The oil in the head ends of the cylinders returns through the control valve and to the tank. When the control lever is moved to FLOAT position, the head ends, rod ends, pressure cham­ bers and return chambers within the valve body are open to each other. The lift cylinder pistons can move in either direction depending on the external forces acting on the bucket. As the pistons move, all excess oil returns to the tank and make-up oil is supplied by the pump. The valve spool is locked in FLOAT position by the float position detent in the spool. The control lever must be manually moved out of FLOAT position. The lift circuit make-up valve housing is mounted .or'. to the control valve body. The make-up valves will unseat and allow oil from the tank to supplement pump flow when the piston rods extend or retract faster than the pump can supply oil to the cylinders.

The lift kickout automatically returns the lift control lever (and lift spool in the control valve) from RAISE to HOLD position when the bucket reaches a preset height.

When the lift control lever is placed in the RAISE position, the lift hydraulic cylinder rods extend and the lift anns raise. As the lift arms raise past a horizontal attitude the lift hydraulic cylinder (3) begins to pivot toward the loader frame. When the lift anns approach the preset bucket height, the lift cylinder contacts the roller (5) on the lift kickout master cylinder (4). The roller pushes the piston in the master cylinder and the master cylinder hydraulically actuates the lift kickout slave cylinder (6). The action of the slave cylinder moves the lift control lever (and the con­ trol valve lift spool) to the HOLD position and the bucket stops at the preset height.

Lift Kickout

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LIFT KICKOUT COMPONENTS 1. Hydraulic tank. 2. Loader frame. 3. Hydraulic lift cylinder. 4. Lift kickout master cylinder. 5. Roller. 6. Lift kickout slave cylinder. 7. Hydraulic tube (con­ nects master cylinder to slave cylinder).

7

920 & 930 LOADER HYDRAULIC SYSTEM

TESTING AND ADJUSTING

LOADER HYDRAULIC SYSTEM . ~-

It::" WARNING

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Hydraulic oil, under pressures that can be higher than 3000 psi (20700 kPa) can remain in the hydraulic systems on this machine after the engine and pump have been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic systems. To prevent possible injury, be sure that the pressure is released before any fitting, hose or com­ ponent is loosened, tightened, removed or adjusted. C

When possible, the bucket must always be flat on the ground before service is started. When it is necessary for the bucket to be raised while tests or adjustments are done, be sure that the lift arms have correct support and the bucket is in the full dump position. Always move the machine to a location away from the travel of other machines. Be sure that other personnel are not near the machine when the engine is running and tests or adjustments are being made.

\Vhen analyzing the hydraulic system, remember that propel' oil flow and con'ect oil pressure are necessary for proper operation. Oil flow is depend­ ent on the pumjJ output which is a function of engine speed. Oil pressure is a result of restriction to the oil flow. In all instances, visual checks and measurements should be made first. Then proceed to operational checks and finally to instrumentation checks. Use the 585123 Hydraulic Testing Group, a stop watch, a magnet, a thermometer and an inch (mm) scale for basic test to measure; 1. Opening pressure of the main pressure relief valve and the tilt circuit relief valves. Low relief valve pressure reduces the lifting and digging capabilities of the machine. Too high opening pressures can reduce hose and com­ ponent life. 2. Lift and tilt circuit drift rates. Circuit drift resul ts from leakage past cylinder piston seals, control valve O-ring seals, poorly seated check or make-up valves and/or excessive spool-to­ valve bore clearances. 3. Lift and tilt circuit cycle times. Excessive circuit cycle times results from leakage, pump wear and/or pump speed.

The analysis of a malfunction will be easier and the conclusion more certain if the following loader hydraulic system fundamentals are remembered. The tilt circuit and lift circuit are arranged in a series circuit. (In bucket dump, pressure oil is not available to the lift circuit.) The hydraulic pump and main pressure relief valve are common to both the lift and tilt circuits. Each circuit has a check valve to prevent cylinder drift during valve spool movement. Each circuit also has mal\e-up valves to supplement pump flow. ".~ Relief valves in the tilt circuit, limit the external pressure imposed on the circuit when the tilt control valve is in the HOLD position.

VISUAL CHECKS

A visual inspection of the system with the engine stopped should be the first step when trouble-shooting a problem. With the bucket low­ ered to the ground and the oil reasonably cool, perform the following inspections: 1. Check the oil level. Slowly loosen the tank filler cap. If oil comes out the bleed hole when the filler cap is loosened, allow tank pressure to bleed off before removing the filler cap.

install a 9S2000 Flow Meter and follow the FLOW METER TEE TEST PROCEDURE~II to isolate the probable leakage source.

2. Remove the filter elements and check for presence of foreign material. A magnet wil1 separate ferrous metal material from non­ ferrous metal and non-metallic sealing material (piston rings, O-ring seals, etc.).

To adjust components located in the tank, it is necessary to drain the tank and remove the tank side cover.

3. Inspect all lines and connections for damage or leaks.

If basic testing reveals internal circuit leakage,

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~ OPERATIONAL CHECKS

The operational check of the system is useful in detecting possible internal leakage, faulty valves or a faulty pump. The speed of cylinder operation can be used as a check of the pump and cylinders.

Example of finding percent of flow loss ...

gpm flow lOSS) ( Pump flow @ 100 psi x 100

1. Observe cylinder extension and retraction for erratic movement. or

2. Listen for pump noise.

* 55) ( *57:5 x 100

=

=

Percent of flow loss

9.5%

If the percent of flow loss is more than 10%, pump performance is not good enough.

Lift control lever should lock in RAISE.

*Numbers in examples are for illustration and are not values for any specific pump or pump condition. See SPECIFICATIONS for pump flow of a new pump at 100 psi and 1000 psi.

Tilt control lever should lock in TILT BACK.

Test On The Machine

4. Observe bucket positioner and lift kickout action.

Bucket positioner mechanism should return the tilt control lever from TILT BACK to HOLD at the pre-set position. Lift kickout should return lift control lever from RAISE to m:rtD at pre-set height. Test and check adjustment of any area where incorrect operation is evident or suspected. (See appropriate section of LOADER SYSTEM TEST PROCEDURES.) When or if hydraulic circuit intemal leakage is determined or suspected, perform pressure checks first. If operation is still slow or sluggish install a 9S2000 Flow Meter to isolate the suspected leakage source (See FLOW METER TEE TEST PROCEDURE-II.) CHECKING PUMP EFFICIENCY

For any pump test, the pump flow, measured in gpm (liter/min) at 100 psi (690 kPa) will be larger than the pump flow at 1000 psi (6900 kPa) at the same rpm.

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Flow loss when expressed as a percent of pump flow is used as a measure of pump performance.

Raise, lower, tilt and tiltback the bucket several times.

3. Listen for relief valve action. Relief valves should not open except at full cylinder ex· tension or retraction when bucket is em pty.

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Install a 9S2000 Flow 'Meter. [See subject, PUMP TESTS (CHART B) in FLOW METER TEE TEST PROCEDURE II, FORM NO. REG­ 0080]. Measure pump flow at 100 psi (690 kPa) and at 1000 psi (6900 kPa) with engine at 2000 rpm. Formula I: gpm (

@

100 psi - gpm @ 1000 gpm @ 100 psi

PSi)

Percent

x 100 = of flow loss

Test On The Bench

If the test bench can not be run at 1000 psi (6900 kPa) at a high rpm, do the first part of the test with the pump shaft rotation at 1000 rpm. Mea­ sure pump flow at 100 psi (690 kPa) and at 1000 psi (6900 kPa). Then in order to measure the pump flow for the last part of the test, see SPECIFICATIONS for: Pump rpm at 100 psi (690 kPa) with the engine at 2000 rpm.

Formula II: (

gpm @ 100 psi - gpm @ 1000 PSi) _ Percent gpm @ 100 psi @ pump rpm x 100 - of flow loss

The difference between the pump flow of two operating pressures is the flow loss.

LOADER SYSTEM TEST PROCEDURES

Method of finding flow loss ...

Lift and Tilt Circuit Speeds

Pump flow at 100 psi'. . 57.5 gpm (liter/min)* -52.0 gpm (liter/min)* Pump flow at 1000 psi. 5.5 gpm (liter/min)* Flow loss .

The oil must be of recommended viscosity and at normal operating temperature to obtain accurate test results. The speed tests are made with the engine at high idle.

9

920 & 930 LOADER HYDRAULIC SYSTEM

TESTING AND ADJUSTING

The speeds in the charts are those of a machine equipped with a general purpose bucket. System speeds similar to the speeds given, indicate that th e circuits are operating normally. Ho wever, the relief valves sho uld be tested to be certain they are set at the proper ratings. If only the lift circuit or only the tilt circuit has slow speeds, check the slow circuit for excessive drifting.

APPROX. TIME IN SECONDS

LIFT CIRCUIT SPEED TESTS

'Raise emply bucket from ground level to lift kickout height.

6.0

'Same as above but, with loaded bucket.

6.6

'lower empty bucket from lift kickout height to ground level with control lever In LOWER Position.

TEST NO.2: Raise the front of the machine off the ground by lowering the bucket. Shut off en· gine and place the lift control lever in LOWER position. Observe if lift cylinder rods extend. TEST NO.3: Raise the empty bucket off the ground. Place the lift control lever in HOLD posi- C tion. Shut off engine and observe if the lift cyl­ inder rods retract. TEST NO.4: Raise the empty bucket off the ground. Shut off engine and place the lift control C lever in RAISE position. 0 bserve if the lift cy1­ inder rods retract. TEST RESULTS

PROBABLE CAUSE

Drlftin9 occurs only in Tesl No.1

1. Lift circuit moke-up valve

Drifting occurs only In Test No.3

1. Lift circuit moke-up volve

Drifting occurs only in Tests No.1 and No.3

1. Lea kage between pistons

APPROX. TIME IN SECONDS

'Move empty bucket from full liltback to full dump. (Lift arms at maximum heigh!).

1.2

'Some os above bUI, with loaded bucket

104

.9

'If both the liFt and nit c,rcults have extremely slow speeds, check For pump malFunctioning. Also check the main pressure relief valve For leakage a r low pressure setting.

Drifting occurs only in Tesls No.2 and No.4

leaking (Ieakoge between valve and seat and/or sea land bodyl.

Drift measurements are the maximum permis­ sible during the time interval shown for the oil temperature in the system.

TILT CYLINDER DRIFT

Drift measurements are the maximum permis­ sible during the time interval shown for the oil temperature in the system. LIFT CYLINDER DRIFT Oil 100° to 1 20° F 1 20 0 to 150° F Over 150° F Temperature (37 0 to 48° C) (48 0 to 65° C) (Over 65 0 CI

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1. Lift circuit check valve

NOTE: Remember thot on O-ring seal fo;lure in the circuit can have the some effect os a main componenr failure.

Lift Circuit Drift

Time interval Minutes

and cylinders. 2. Leakage between lift cir­ cuil control valve spool ond body.

Tilt Circuit Drift

'Move bucket from level to full tiltbock (bucket on the ground).

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Ihead ends) leaking.

3.5

CAUTION: Set the lift kickout so the lift cylinder piston rods stop .25 in. (6.4 mm) from end of their strokes.

Maximum permissible Drift

(rod ends) lea king.

3.4

Some as above but, with control lever in FLOAT position.

TILT CIRCUIT SPEED TESTS

TEST NO. 1: Raise the front of the machine off the ground by lowering the bucket. Place the lift control lever in HOLD position. Shut off the engine and observe if lift cylinder rods extend.

in.

mm 9.7

.38

5

in.

mm

.38

9.7

2.7

in.

mm

.38

9.7

1.7

Oil 1 00° to 1 20° F 120 0 to 150°F Over 150° F Temperature (37° to 48 0 C) (48° to 65°CI (Over 65° C) Maximum permissible Drift Time interval Minutes

in.

mm

in.

mm

in.

mm

.62

15.8

.62

15.8

.62

15.8

5

2.7

1.7

TEST NO. L Raise the front of the machine off the ground by partially dumping the bucket. Place the tilt control lever in HOLD position. Shut off engine and observe if the tilt cylinder rods extend.

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920 & !:UU LOADt:H HY[fH-AUlIL ~y~ I t::IVl