Return to Master Table of Contents Page 25 Hydraulic System Troubleshooting, Testing and Adjustment Problem Possible Causes Remedies Swing movement is in one direction only. Check to see that pilot pressure is the same right and left. If pilot pressure is unequal, clean or repair piping or repair/ replace valve. Swing control valve spool may be stuck. Repair/Replace the swing control valve. Swing relief valve may be faulty. Repair/Replace the swing relief valve. No rotation and: Pressure at swing motor inlet increases. Swing brake not releasing. Check brake engagement and disengagement; check release pressure. Internal damage to gearbox drive train.
Replace broken gears and drive train assemblies. Overload. Reduce load weight. Pressure at swing motor inlet shows no increase, and the swing motor is making irregular noises. Swing motor drive shaft damage. Replace swing motor. Internal damage to gearbox drive train. Repair/Replace broken or faulty assemblies. Pressure at swing motor inlet shown no increase, but without irregular noises from the swing motor. Hydraulic pump or valve problem. Troubleshoot hydraulic system. Oil Leakage: From drive shaft From bolted connections or other assembled surfaces. Oil seal damaged Assembly compound (joint sealer) old and not sealing, bolt not tight or flange warped.
Replace oil seal Disassemble and check mating surfaces. Reapply Loctite; torque bolts to specifications. Excess heat: Gearbox casing becomes excessively hot, with or without irregular noises, during operation. Low oil level. Replace oil; refill to specified level. Bearings or gears worn but not completely inoperative. Repair or replace gearbox. TROUBLESHOOTING - HYDRAULIC PROBLEMS Problem Possible Causes Remedies Attachment cylinders, swing and travel motors are all inoperable. Loud noises are heard from main pump assembly.
Main pump(s) malfunction Repair or replace Low oil level in hydraulic system Refill Main pump inlet (oil supply) piping or hose damaged Repair or replace Attachment cylinders, swing and travel motors are all inoperable. No usual or loud noises can be heard. Pilot pump malfunction Repair or replace Pilot cutoff solenoid stuck Repair or replace Pilot cutoff switch faulty Repair or replace Engine/pump flex coupling damaged Replace flex coupling