Brake Accumulator Charging

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740B 740B Artic Articula ulate ted d Truc Truck k L4E0 L4E000 0001 01--UP (MAC (MACH HINE) INE) POW POWERED ERED BY C15 Eng Engine ine((SEBP SEBP59 5908 08 - 16) 16) - Docume ocume… …

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Product: ARTICULATED TRUCK Model: 740B ARTICU LATE LATED D TRUC K L4E Configuration: 740B Articulated Truck L4E00001-UP (MACHINE) PO WERED BY BY C 15 Engine

Testing and Adjusting 735B, 740B and 740B EJECTOR Articulated Trucks Machine Systems Me dia Num ber -UENR0210-00

P ublicat ion D a t e -01/04/2011

D at e Upda t e d -05/04/2011

i04155969

Brake Accumulator (Service) - Test and Charge SMCS - 4263-045; 4263-081; 4263-535

Pressu Pre ssure re Test

Personal injury or death can result from improper accumulator charging. Dry Nitrogen is the only gas approved for use in the accumulator. Chargin Charging g the accumulator accumulator with with oxyge n w will ill cause an explosion. e xplosion. Th This is danger will not happen if nitrogen cylinders with standard CGA (Compr (Compree sse ss e d Gas Association Ass ociation,, Inc.) Num N umber ber 580 connections connections are are used. When ordering nitrogen gas, be sure that the cylinders are equipped with CGA Number 580 connections. Do not use color codes or other methods of identification to tell the difference between nitrogen and oxygen cylinders Never use an adapter to connect your nitrogen charging group to a valve outlet used on both nitrogen, oxygen, or other gas cylinders. BE SURE YOU USE DRY NITROGEN (99.8% purity).

1. Park Pa rk the mac machi hine ne on a level level surface. 2. Move the transmission transmission control to the N positi po sition on and move move the parkin park ing g brake control c ontrol to the the ENGAGED  positi  position on.. Shut Shut off off the the eng engine. 3. Install the steeri steer ing frame frame lock. Refer Re fer to Opera Op erati tion on and Maintenance Maintenance Manu Ma nual, al, "Ste "Steering ering Fram Fra me Lock" Lock ". 4. Connect a 25000 kPa kP a (3600 psi ps i) pressure gaug gaugee to the the test port for for the the front front brake pressure. C Conn onnect ect a https://sis.cat.com/s https://sis.cat.com/sisw isweb/sis eb/sisweb/techdoc/techdoc_p web/techdoc/techdoc_p rint_page .jsp?returnurl=/sisw .jsp?returnurl=/sisweb/sis eb/sisweb/medi web/medi as… as…

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25000 kPa (3600 psi) pressure gauge to the test port for the center brake pressure. Reference Refer to Testing and Adjusting, "General Troubleshooting Information" for the location of the test fitting for the machine that is being tested.

5. Start the engine. Operate the engine at low idle for 1 minute in order to charge the braking system. 6. Shut off the engine. Make repeated light applications of the service brakes and observe the pressure on the  pressure gauges. As successive service brake applications are made, the pressure readings will fall. The  pressures will suddenly fall to zero. The pressures should be 5600 kPa (810 psi) before falling to zero. 7. Remove the pressure gauges from the machine. 8. Remove the steering frame lock. Refer to Operation and Maintenance Manual, "Steering Frame Lock".

Check the Precharge on the Machine Table 1 Required Tools Tool

Part Number

Description

Qty

(A)

152-2023

Nitrogen Charging Fitting Gp

1

(B)

175- 5507

Nitrogen Charging Group

1

(C)

9U-6741

Adapter

1

8T-7860

Connector

1

5P-2937

O-Ring Adapter

1

2S-5244

Fitting

1

8S-4599

Coupling

1

5P-8998

Fitting

1

3J-7354

O-Ring Seal

1

1P-7326

Washer

1

(D)

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Illustration 1

g00805723

(B) 175-5507 Nitrogen Charging Group

1. Disconnect hose (3) from tee (4) .

Illustration 2

g00805742

2. Connect Tool (C) to tee (4) .

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Illustration 3

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(A) 152-2023 Nitrogen Charging Fitting Gp

3. Connect Tool (D) to Tool (A) .

Illustration 4

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4. Connect Tool (D) to Tool (C) . 5. Release the pressure from the service brake system. Refer to Step 6 in "Pressure Test".

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Illustration 5

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Accumulator  (5) Protective cover  (6) Seal for the g as valve (7) Gas valve

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6. Unscrew protective cover (5) and remove seal (6) from gas valve (7) .

Illustration 6

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7. Disconnect hose (11) from valve (10) at point (15). Ensure that the valve is closed.

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Illustration 7

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(8) Press ure gauge (16) Hos e (17) Valve body (18) Gas valve key drive (19) Purge valve (20) Adapter  (21) Gas valve key

8. Ensure that purge valve (19) is closed. Install adapter (20) on the accumulator. Ensure that gas valve key (21) engages the accumulator gas valve. Fully tighten the adapter. 9. Use a half inch ratchet wrench in order to turn gas valve key drive (18). Turn the gas valve key drive counterclockwise in order to open gas valve (7) on the accumulator. 10. Pressure in the accumulator will be displayed on pressure gauges (8) and (9). For the required precharge  pressure at 21 °C (70 °F), refer to Table 2. Note: Some earlier machines may be installed with the higher pressure accumulator.

Table 2 https://sis.cat.com/sisweb/sisweb/techdoc/techdoc_p rint_page .jsp?returnurl=/sisweb/sisweb/medi as…

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Machine

Service Brake Accumulator

Precharge Pressure

251-8265 StandardAccumulator

Field replacement is 2518266.

5650 ± 150 kPa (820 ± 22  psi) (1)

223-2444 Accumulators for cold start machines

Field replacement is 2232445.

3100 ± 50 kPa (450 ± 7.3 psi)

348-9291 Accumulator for cold start machines in Canada

Field replacement is 3491689.

3100 ± 137 kPa (450 ± 20  psi)

( 1 ) If you check the n itrogen precharge press ure and t he precharge pres su re is less than 3100 kPa (450 ps i), then o nly

charge the accumulators to 3100 kPa (450 psi). Charging the accumulator to a higher pressure may initiate a  premature failure of the accumulator.

Note: When you check the nitrogen precharge pressure, there may be slight oil leakage from the nitrogen charge valves of the accumulators. This oil leakage is normal. The leakage is because of a small quantity of  oil in the side of the accumulator that contains the nitrogen. The oil was added during the manufacture of the accumulator.

11. If the pressure is correct, turn gas valve key drive (18) clockwise to close gas valve (7). Open valve (10) in order to release the pressure from the Tooling. Proceed to Step 14. 12. If the pressure is above the required precharge pressure, then the pressure must be decreased. a. Slowly open valve (10) in order to reduce the pressure in the accumulator to the required precharge  pressure. Close the valve when the required pressure is reached.  b. Turn gas valve key drive (18) clockwise to close gas valve (7). Open valve (10) in order to release the pressure from the Tooling. 13. If the pressure is below the required precharge pressure, then the pressure must be increased. a. Reconnect hose (11) to valve (10) at point (15) .  b. Attach regulator (14) to a nitrogen cylinder. Ensure that adjustment screw for the regulator is backed out completely in order to close the regulator. c. Turn gas valve key drive (18) clockwise to close gas valve (7) . d. Open the shutoff valve on the nitrogen cylinder. The pressure in the nitrogen cylinder will be displayed on gauge (13). e. Open the adjustment screw on regulator (14) until pressure gauge (12) reads about 200 kPa (30 https://sis.cat.com/sisweb/sisweb/techdoc/techdoc_p rint_page .jsp?returnurl=/sisweb/sisweb/medi as…

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 psi). Open valve (10) and open purge valve (19) for a few seconds in order to purge air from the lines. Close purge valve (19) and then close valve (10) . f. Use a half inch ratchet wrench in order to turn gas valve key drive (18). Turn the gas valve key drive counterclockwise in order to open gas valve (7) on the accumulator. g. Open the adjustment screw on regulator (14) until the regulated pressure reads 300 kPa (45 psi) above the required precharge pressure. h. Open valve (10). Wait for 2 minutes in order to stabilize the temperature of the gas in the accumulator. i. Close valve (10) and close regulator (14). Close the shut off valve in the nitrogen cylinder.  j. Slowly open purge valve (19) and allow the accumulator pressure to fall. Close the purge valve when the pressure falls to the required pressure. k. Turn gas valve key drive (18) clockwise to close gas valve (7). Open valve (10) and then open purge valve (19) in order to release pressure from the Tooling. Remove the Tooling from the nitrogen cylinder. 14. Remove the Tooling from the accumulator. Tighten gas valve (7) . 15. Install seal (6) into gas valve (7). Screw on protective cover (5) . Note: The accumulators from parts service are shipped without a gas charge. The accumulators from parts service must be charged with nitrogen gas prior to installation on the machine. Copyright 1993 - 2012 Caterpillar Inc. All Rights Re served. Private Network For SIS Licensees.

Wed Dec 19 2012 11:51:09 GMT+0400 (Arabian Standard Time)

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