Return to Master Table of Contents Page 12 Hydraulic System Troubleshooting, Testing and Adjustment PILOT PRESSURE ADJUSTMENT AND TESTING WARNING! This procedure should be done with two people. To reduce the chance of accident or unintended start-up, one person should remain at the operator’s control stand while checks and adjustments are made. Vent hydraulic pressure from the reservoir before breaking the seal on fittings to install two in-line "t-style" adapters and test gauges (60 bar/1,000 psi) at the gear pump outlet port, and at the joystick control valve pilot line. Start the engine and turn the engine speed control dial to the maximum setting.
After the excavator has been operated long enough to reach normal operating temperature, back off the engine control dial to minimum rated RPM speed. With all controls in neutral, make sure the left console control stand is locked in the down (operating) position and check pressure at the gear pump outlet port and at the joystick. If gear pump pressure is outside the tolerance specified in the table, adjust gear pump relief pressure by loosening the lock nut and turning the set screw in (clockwise) to increase pressure, or turning it out to decrease it. NOTE:
Be aware that serial number changes and variation in the joystick assemblies used on different excavators could produce slight change in actual performance characteristics. Comparison of part numbers to serial numbers stamped on your assembly may be required, if questions or doubt exists. IMPORTANT Top off the hydraulic fluid reservoir if there is any measurable loss of hydraulic oil during test gauge and adapter fitting installation. Engine RPM Pilot Pressure @ Pump Pilot Pressure - Joystick Minimum Speed Setting (full left) on Speed Control Dial 40 ±5 bar (580 ±73 psi) 40 ±5 bar (580 ±73 psi)