FILTER NX MISC 2439965 - Caterpillar

An internal oil leak in the brake release system will cause too much friction between the brake discs and the plates. The friction can damage the components when the machine is moving.
Remove the air from the brake release system. Perform the procedure for the Parking Brake in the Testing and Adjusting, "Brake System Air - Purge".
Illustration 1 g02204193
View of the back of the rear axle housing
Illustration 2 g02204033
View of Area "A"
(1) Pressure tap for the parking and secondary brake release pressure
Use a coupler and a hose to connect a 8T-0857 Pressure Gauge ( 0 to 10000 kPa (0 to 1450 psi)) at pressure tap (1).
Start the engine. Operate the engine at low idle.
Move the transmission lever to the NEUTRAL position.
Operate the engine until the pressure stops increasing. Then, stop the engine.
Record the pressure decrease in the first minute in Table 2. Note: If the oil pressure at pressure tap (1) has not decreased 690 kPa (100 psi) or more in the first minute, then the leakage is not severe enough to affect the brake release system. Doing a leakage check for each wheel is not necessary at this time.
Table 2
Decrease In Pressure In The First Minute
Plugged Wheel Pressure Decrease
No plugged wheels
Left Rear
Right Rear
Left Front
Right Front
Move the transmission lever to the PARK position. Plug Rear Wheels and Check System Pressure
If the oil pressure at pressure tap (1) has decreased 690 kPa (100 psi) or more in the first minute, then the leak must