PLATE 4256182 - Caterpillar

Reverse Relief Valve (High Pressure)
Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine.To prevent possible injury, perform the procedure that follows before testing and adjusting the power train.
Personal injury can result from hydraulic oil pressure and hot oil.Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide", for tools and supplies suitable to collect and contain fluids in Caterpillar machines.Dispose of all fluids according to local regulations and mandates.
Note: Perform the Relief Valve (Charge) - Test and Adjust before doing this test.
Table 1
Required Tools    
8T0861     Pressure Gauge 60000 kPa     1    
Before you perform the testing and adjusting, the following steps must be followed:
Place the propel control lever in NEUTRAL.
Place wedges of wood around the wheels and around the drum.
Illustration 1 g00695749
Engine Compartment (1) Brake release line
Remove brake release line (1) from the brake solenoid valve. Plug the brake release line.
Illustration 2 g00695753
Propel Pump (2) Propel pump. (3) Cap for the relief valve (forward). (4) Relief valve pressure tap (reverse). (5) Relief valve pressure tap (forward). (6) Cap for the relief valve (forward).
Connect two pressure gauges to pressure taps (4) and (5) .
Illustration 3 g00695776
Cross Section Of The Pump Head (3) Cap for the relief valve (forward). (6) Cap for the forward relief valve. (7) Adjustment screw. (8) Relief valve cartridge.
Loosen the adjuster nut on the pressure override relief valve (POR). Turn adjustment screw (7) clockwise. Turn only half of a turn. Tighten the locknut.
Start the engine. Run the engine at high idle.
Move the propel control lever to the full reverse direction. Read the maximum pressure at pressure tap (4). The relief valve pressure should be 45000 1380 kPa (6527 200 psi).
Illustration 4 g00594804
Relief Valve Cartridge (8) Relief valve cartridge. (9) Locking setscrew. (10) Spindle (adjuster).
If the relief valve pressure is not correct, the following steps must be done in order to adjust the reverse main relief valve:
Stop the engine.
Remove the cap on the reverse relief valve.
Remove relief valve cartridge (8). Reinstall the cap on relief valve (3), so the oil does not leak during the adjustment to the cartridge.
Clamp the cartridge in a soft vise jaw. See the arrows in illustration 4. Loosen locking setscrew (9) with a 3 mm allen wrench.
Use a 5 mm wrench to turn