OPERATOR AR 2204994 - Caterpillar

Table 1
Required Tools    
Part Number    Part Description    
8T-5320     Hydraulic Test Group    The main relief valve is a component of the inlet valves in the implement control valve. The main relief valve is in all the implement hydraulic circuits. The main relief valve is used by the circuits for bulldozer lift and for the ripper.
Personal injury or death can result from sudden machine movement.Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine.To help prevent possible injury, perform the procedure that follows before testing and adjusting the hydraulic and steering system:
Move the machine to a level location before the pressure test. Raise the hydraulic oil to operating temperature. Stop the engine. Move the control levers for the bulldozer and for the ripper to each position several times. This operation releases the pressure in the lines.
Illustration 1 g00484308
Blocking plate installation (1) Blocking plate
If the machine has a ripper or a tilt cylinder, go to Step 2. Otherwise take two blocking plates from the hydraulic test group. Disconnect the rod end hydraulic line from each lift cylinder. Install a blocking plate (1) in each line.
Put a 0 to 28000 kPa (0 to 4000 psi) pressure gauge on the 6V-3081 Hose. These tools are included in the 8T-5320 Hydraulic Test Group .
Remove the floorplates.
Illustration 2 g00499037
Control valve stack (2) Pressure tap beneath block
Connect the gauge and hose to pressure tap (2) .
Start the engine and operate the engine at high idle. Lift the ripper to the maximum height. Raise the blade to the maximum height. Watch the test gauge. Slowly move the control lever to the RAISE position. The high reading on the gauge is the pressure setting of the main relief valve. The pressure setting of the main relief valve is 22750 300 kPa (3300 45 psi). Do not hold the lever in the RAISE position for more than 10 seconds under test conditions. Do not use the control lever for one minute after the test.
This step adjusts the maximum pressure of the main relief valve. Lower the bulldozer blade and lower the ripper to the ground. Stop the engine. Loosen locknut (3) on the main relief valve. Turn retainer (4) clockwise for an increase in the pressure setting of the main relief valve. Turn retainer (4) counterclockwise for a decrease in the pressure setting of the main relief valve.
Illustration 3 g00499081
Main relief valve (3) Locknut (4) Retainer
When the pressure setting is correct, tighten locknut (3) to a torque of 50 7 N m (37 5 lb ft). Remove the test equipment. Install the floorplates.