Main Relief Valve Pressure Test
Do not run the machine against the brake for
more than five seconds.
Do the Propel Charge Relief Valve Pressure Test
before doing the main relief valve test.
Make sure that the parking brake is applied. Make sure
the propel control lever is in neutral.
Parking Brake Valve
(1) Brake wire connector.
Disconnect brake wire connector (1). This allows the
parking brake to stay applied during the test.
Flushing Valve Pressure Test
(2) Drum forward test port. (3) Axle forward test port.
Connect two 60 000 kPa (9000 psi) pressure gauges
from the 4C4892 ORFS Fittings Group to test ports (2)
Start the engine and run at high idle.
Move the speed selection switch to the HIGH speed
Release the parking brake.
Slowly move the propel control lever in the forward
direction. Look at the pressure gauge on test port (2)
and record the relief valve pressure of the drum pump in
forward direction. Look at the pressure gauge on test
port (3) and record the relief valve pressure of the axle
pump in forward direction. The relief valve pressure of
both the pumps should be 29 900 kPa (4337 psi).
If the relief valve pressures are not correct, check the
following: low charge pressure, shuttle or relief valves in
the flushing valve stuck, internal damage to front gear
reducer or rear propel motor, damage to end reduction
case, carrier, or wheel assemblies, damage to drum
support assembly on vibratory side of drum or swap
cartridges with each other to check if one is stuck open.
If cartridge is bad it will need to be replaced. Move the
control lever back to neutral. Stop the engine.
Remove the relief valve and install a new valve. Tighten
to a torque of 136 to 163 Nm (100 to 120 lb-ft).
Repeat Steps 4, 5, 6, and 7 to recheck the pressure
When the correct relief valve pressure is obtained, move
the control lever to the NEUTRAL position. Stop the
Remove the pressure gauges from test ports (2) and
(3). Reconnect the brake wire connector.