Brake Accumulator Charging

12/19/12 740B Articulated Truck L4E00001-UP (MACHINE) POWERED BY C15 Engine(SEBP5908 - 16) - Docume…

1/10https://sis.cat.com/sisweb/sisweb/techdoc/techdoc_print_page.jsp?returnurl=/sisweb/sisweb/medias…

Shutdown SIS

Previous Screen

Product: ARTICULATED TRUCKModel: 740B ARTICULATED TRUCK L4EConfiguration: 740B Articulated Truck L4E00001-UP (MACHINE)POWERED BY C15 Engine

Testing and Adjusting 735B, 740B and 740B EJECTOR Articulated Trucks Machine SystemsMedia Number -UENR0210-00 Publication Date -01/04/2011 Date Updated -05/04/2011

i04155969

Brake Accumulator (Service) - Test and Charge

SMCS - 4263-045; 4263-081; 4263-535

Pressure Test

Personal injury or death can result from improper accumulator charging.

Dry Nitrogen is the only gas approved for use in the accumulator.Charging the accumulator with oxygen will cause an explosion. Thisdanger will not happen if nitrogen cylinders with standard CGA

(Compressed Gas Association, Inc.) Number 580 connections are used.

When ordering nitrogen gas, be sure that the cylinders are equipped withCGA Number 580 connections. Do not use color codes or other methodsof identification to tell the difference between nitrogen and oxygen

cylinders

Never use an adapter to connect your nitrogen charging group to a valveoutlet used on both nitrogen, oxygen, or other gas cylinders. BE SUREYOU USE DRY NITROGEN (99.8% purity).

1. Park the machine on a level surface.

2. Move the transmission control to the N position and move the parking brake control to the ENGAGEDposition. Shut off the engine.

3. Install the steering frame lock. Refer to Operation and Maintenance Manual, "Steering Frame Lock".

4. Connect a 25000 kPa (3600 psi) pressure gauge to the test port for the front brake pressure. Connect a



25000 kPa (3600 psi) pressure gauge to the test port for the center brake pressure.

ReferenceRefer to Testing and Adjusting, "General Troubleshooting Information" for the location of thetest 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 thepressure gauges. As successive service brake applications are made, the pressure readings will fall. Thepressures 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

(D)

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



Illustration 1 g00805723

(B) 175-5507 Nitrogen Charging Group

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


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




(A) 152-2023 Nitrogen Charging Fitting Gp

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


4. Connect Tool (D) to Tool (C) .

5. Release the pressure from the service brake system. Refer to Step 6 in "Pressure Test".




Accumulator

(5) Protective cover

(6) Seal for the gas valve

(7) Gas valve



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


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






(8) Pressure gauge

(16) Hose

(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



Machine Service Brake

Accumulator

Precharge Pressure

StandardAccumulator

251-8265

5650 ± 150 kPa (820 ± 22

psi) (1) Field replacement is 251-8266.

Accumulators for cold start machines

223-2444

3100 ± 50 kPa (450 ± 7.3 psi)

Field replacement is 223-

2445.

Accumulator for cold start machines in

Canada

348-9291

3100 ± 137 kPa (450 ± 20psi)

Field replacement is 349-1689.

( 1 ) If you check the nitrogen precharge pressure and the precharge pressure is less than 3100 kPa (450 psi), then onlycharge the accumulators to 3100 kPa (450 psi). Charging the accumulator to a higher pressure may initiate apremature 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 ofoil 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



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 Reserved.Private Network For SIS Licensees.

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

Documents

Brake Accumulator Charging