BOOM AS 4756699 - Caterpillar

Illustration 1 g02708859
Install suitable 35000 kPa (5000 psi) pressure gauges in the main pressure test point (8) of the piston pump for the brake system. Main pump pressure is 2100 700 kPa (3000 100 psi). Refer to Illustration 1
Start the engine and raise and lower the body 5 times in order to warm and circulate the hydraulic oil.
Set engine at low idle and record the brake pressure as the base line start for the test.
Turn off the engine. Press and release the service brake pedal up to 60 times to exhaust the pressure in the brake accumulators.Note: This procedure must be consistent throughout the test period. Depress the service brake pedal the same number of times for each test.
Start the engine and set at low idle. Record the time that passes before the low brake pressure warning buzzer stops and the warning light goes out. (level 3 Warning). Continue to run the engine for 30 seconds and then record the brake pressure.
Turn off the engine and repeat steps 5 and 6 Repeat these steps 20 times. Record each cycle time for charging the accumulators and the brake system pressure.
If the charge time between test 1 and test 20 is within 5 seconds or less, then the pump efficiency is within specification. Go to step 12.
If the time between test 1 and test 20 has increased by 5 seconds, or more, further investigation is required. Perform steps 10 and 11.Note: This test result is an indication of a decrease in brake pump efficiency.
Illustration 2 g02708879
(6) Scratches - Can be felt with a fingernail. This component must be replaced. (7) Polish marks - No depth or ridges. These marks are acceptable
Remove the brake pump. Disassemble the pump and check for wear on the port plate and contamination within the pump. Illustration 2 will help determine what wear is acceptable. For more reference information refer to Reuse And Salvage Guidelines, SEBF8032-02, "Guideline for Reusable Parts and Salvage Operations".
On finding that the port plate is scratched or scored and/or there are signs of contamination skip step 12. Proceed to ""Cleaning the Brake/Hoist System"" in this publication.
No further action is required. Remove all test equipment and wheel blocks.Cleaning the Brake/Hoist System
Table 1
Item     Qty     Part Number     Description    
5     1     6E-5066     Screen    
Take a hydraulic oil sample from the tank and send the sample to the S.O.S lab.
Drain the hydraulic oil and remove the tank top to inspect the inside of the tank.
Use suitable solvent to flush tank and a lint free cloth to clean the inside of the tank.
Replace the hydraulic return filters.
Illustration 3 g02709777
Illustration 4 g02708916
Illustration 5 g02708917
(1) Manifold (5) Screen
Replace the 6E-5066 Screen (5) in the 337-8683 Manifold Gp (1) .
Raise the cab and remove hose (2) and fitting (3) from manifold (1) .
Use a suitable hex wrench to remove screen (5) from manifold (1) and discard.
Install a new 6E-5066 Screen (5) into manifold (1).
Torque the screen to 7 N m (62