OPERATION 3.24 TROUBLE SHOOTING 3.24.2 HYDRAULIC SYSTEM 279 Problem Probable cause Poor hydraulic system perfor- mance G Hydraulic oil not at operating temperature. G Engine speed too low. G Reservoir low on oil G Restrictions in lines G Cooling circuit, pump control system and/or pilot control circuit defective. G Internal leakage (control blocks, valves or power units.) G Pressure lines twisted or kinked G Spool not in full stroke. G Relief valve defective, or out of adjustment. G Worn cylinders. G Defective hydraulic pump. Excessive oil temperature G Low oil level G Incorrect viscosity or type of oil G Hydr. oil cooler clogged with dirt. G Oil cooler fan defective or wrong speed.
G Cooling circuit defective G Pump control system defective G Spool not in full stroke. G Internal leakage (control blocks, valves or power units) G Worn pump components G Job conditions (high temperature of materials being handeld) Jerky motion of power cylinders G Piston rod bent G Piston sticking G Inside diameter of cylinder tube partially increased or scored G Air in control circuit G Oil too cold G Valve spool sticking, centering springs defective G Pump and/or engine control system defective G Valve of power circuit defective Noise when slewing G Inssufficient lubrication of swing ring gear and/or slewing connection.
G Slewing connection mounting bolts loose G Drive pinion worn G Swing gear bearings worn G Sun gear or planetary pinions worn G High pressure circuit valves defective G Anti-caviation valves sticking Excessive oil foaming G Air in hydraulic system G Poor quality oil G Excessive by-passing of oil over relief valves G Pressure hoses badly twisted or kinked G Restricted oil flow due to foreign matter G Breather on the reservoir clogged. G Relief valve improperly adjusted