VALVE GP-RELIEF 2039582 - Caterpillar

Required Tools
Illustration 1 g02726620
Tooling (B)
Table 3
Tool    Item    Part Number    Description    Qty    
B     B1     8T-0856     Pressure Gauge
(0 to 6,000 kPa (0 to 870 psi))     1    
B2 6V-3989     Fitting     1    
B3 6V-4143     Quick Connect Coupler     2    
B4 177-7860     Hose As (10 ft)     1    Test Preparation - Accumulator Leak Down
Move the machine to a smooth horizontal location.
Engage the parking brake.
Lower all of the implements.
Stop the engine.
Turn the key to the ON position. Make sure that the implement lockout switch is turned to the UNLOCKED position. Move the implement control levers to all positions several times in order to release any pressure in the hydraulic system.
Illustration 2 g02791179
(1) Accumulator (2) Pilot manifold (HPS) Pressure tap
Attach tooling (B) to pressure tap (HPS) .Test Procedure - Accumulator Pilot Oil Pressure Leak Down
Start the engine. Warm the hydraulic oil to a minimum temperature of 65° C (150° F).
Record the pressure reading on pressure tap (HPS) .
Stop the engine. Turn the key to the ON position but do not start the machine.
With the implement lockout switch in the UNLOCKED position, record the pressure reading at pressure tap (AP) .
The pressure reading should not drop more than 700 kPa (101 psi) in 2 minutes. If a pressure drop greater than 700 kPa (101 psi) occurs, the pilot oil system should be checked for excessive leakage.Adjustment Procedure - Pressure Leak Down
There are no adjustments that can be made to reduce pressure leaks in the system. Investigate the components of the charging system to determine the cause of the system leakage.Test Preparation - Accumulator Charge Pressure
Move the machine to a smooth horizontal location.
Engage the parking brake.
Lower all of the implements.
Stop the engine.
Turn the key to the ON position. Make sure that the implement lockout switch is turned to the UNLOCKED position. Move the implement control levers to all positions several times in order to release any pressure in the hydraulic system.
Illustration 3 g02791179
(1) Accumulator (2) Pilot manifold (HPS) Pressure tap
Attach tooling (B) to pressure tap (HPS) on pilot manifold (2) . Use the pressure tap (HPS) for the accumulator charge pressure.Test Procedure (Accumulator Charge Pressure)
Start the engine. Warm the hydraulic oil to a minimum temperature of 65° C (150° F).
Operate the engine at HIGH IDLE.
Exercise the implement hydraulics. At the accumulator, the pilot pressure at tooling (AP) should be 3275 170 kPa (475 25 psi).
Shut off the engine. Turn the key to the ON position. The accumulator charge pressure should remain steady until an implement control is exercised.
With the implement lockout switch in the UNLOCKED position, move the implement control out of the HOLD position in any direction in order to actuate a function. Return the handle to the hold position between activations of the handle. Quick movement of the handle should increase the accuracy of this test.
With the handle in the HOLD position between activations, record the reading on tooling (B) .
Repeat Step 5 and Step ,6 recording the