HOSE AS 3981372 - Caterpillar

Illustration 1 g00740370
Pump Compartment (1) Right case drain return port (2) Charge relief valve test port for the right pump (3) Adjustment screw for the right charge relief valveNote: The charge relief valve test port for the left pump is located on the left charge pump filter. The adjustment screw for the left pump charge relief valve is located on the bottom of the left propel pump.
Attach a pressure gauge on right case drain return port (1) .
Start the engine and run the engine at high idle.
Engage the parking brake control.
Observe the gauge reading for the case drain pressure and record the gauge reading for future testing. Place the engine in low idle and stop the engine. Remove the pressure gauge.
Attach a pressure gauge to the left case drain return port that is located on the bottom of the left propel pump.
Repeat Step 2 through Step 4.
Place the engine in low idle. Stop the engine.
Attach the gauge to charge relief valve test port (2) .
Start the engine and run the engine at high idle.
Activate the parking brake control.
Observe the gauge reading and record the gauge reading. The gauge reading is not the pressure for the pump charge relief valve. The pressure for the charge relief valve is the gauge reading minus the case drain pressure that was recorded previously. The corrected pressure for the pump charge relief valve should be 2550 140 kPa (370 20 psi).Note: When you perform the procedure for the main relief valve pressure, you will need the gauge reading that was recorded in Step 11.
If the pressure reading is not correct, adjustment is necessary. Stop the engine. Locate adjustment screw (3) for the right charge relief valve. Loosen the locknut. Turn the adjustment screw clockwise or counterclockwise. Tighten the locknut after you are finished with the adjustments.Note: Turn the adjustment screw clockwise in order to increase the pressure for the pump charge relief valve. Turn the adjustment screw counterclockwise in order to decrease the pressure for the pump charge relief valve. When you turn the adjustment screw in order to complete one full turn, the pressure for the pump charge relief valve will change approximately 345 kPa (50 psi).
After an adjustment is made, repeat Step 9 through Step 12 in order to recheck the pressure for the pump charge relief valve.
When the correct pressure is obtained, stop the engine. Remove the gauge from charge relief valve test port (2). Connect the gauge to the charge relief valve test port for the left propel pump. Repeat Step 9 through Step 13 until the correct pressure for the pump charge relief valve is obtained on the left propel pump.
Stop the engine. Remove the gauge from the test port.