ENGINE AR 9E1287 - Caterpillar

Adjustment of the Main Relief Valve
Note: The main relief valve setting is higher than the setting of the pressure compensator.
Loosen locknut (3) on left main relief valve (2). Mark the original position of adjuster (4). Turn adjuster (4) counterclockwise by one full turn in order to reduce the pressure setting of the relief valve. Hold adjuster (4) and tighten locknut (3) .Note: One full turn decreases the pressure setting by approximately 12000 kPa (1740 psi).
Start the engine. Run the engine at high idle.
Raise the bucket off the ground. Move the bucket to the full RACKBACK position. Hold the bucket in this position.
Read the gauge that is connected to pressure tap (1) .
The pressure reading should be 20800 340 kPa (3000 50 psi).
If the opening pressure of the relief valve is not within the specified range, the relief valve must be adjusted.
Loosen locknut (3) on left main relief valve (2). Turn adjuster (4) clockwise in order to increase the pressure setting of the relief valve. Turn adjuster (4) counterclockwise in order to decrease the pressure setting of the relief valve. Adjust left main relief valve (2) in order to obtain the pressure in Step 5.
After the pressure in Step 5 is reached, turn adjuster (4) clockwise by one full turn in order to increase the pressure setting.
After the relief valve is adjusted hold adjuster (4) and tighten locknut (3) to 50 7 N m (35 5 lb ft).
Run the engine at low idle in order to allow the hydraulic oil to cool.
After the hydraulic oil cools, stop the engine.