JLG X23J - X700AJ Service Manual - Manual (Page 131)

SECTION 3 - CHASSIS & TURNTABLE
3-104 – JLG Lift – 3121448
Troubleshooting
Condition Cause Correction
Motor will not turn No oil
Pomp broken
Relief valve stuck open or set too low
Fill reservoir to proper oil level.
Replace pump.
Clean and free relief valve spool and
Adjust to proper setting.
Slow operation Low oil viscosity
Worm pomp
Extremely high fluid temperatures
Relief setting too low
Use proper viscosity oil.
Repair or replace pump.
Increase reservoir size or add oil cooler.
Set relief valve for proper pressure.
Erratic motor operation Relief setting too low
Air sucked in inlet side of pump
Set relief valve for proper pressure.
Tighten pipe fitting on pump inlet side.
Motor turns in wrong direction Wrong piping
The valve timing is incorrect due to a
disassembling error.
Reverse the piping
Disassemble and reassemble the unit
and correct valve timing.
Fluid leakage Loose bolts or plugs.
Scratched or abraded O-ring
Scratched or abraded X-ring
Scratched or abraded Floating seal
Tighten bolts and plugs by the correct
torque.
Replace the O-ring with a new one.
Replace the X-ring with a new one.
Lower the drain pressure until it is within
the allowable range.
Replace whole the Spindle / wheel
ass’y.
Abnormal sound Air is remaining in the circuit and motor.
Pump cavitation.
Broken bearing
Bleed air completely.
Remove substance clogging the suc-
tion filter.
Enlarge the dia. Of the suction pipe of
the pump.
Raise the boost pump pressure.
Replace whole the Spindle / wheel
ass’y.
Bad changing Low speed
ÍÎ High speed Remained pressure in the pilot line
The backpressure is high.
Orifice contaminated
Spool locked
Bleed remained pressure or decrease
remained pressure 0.5 MPa or below.
Lower the drain pressure 0.5 MPa or
below.
Remove the contamination.
Replace the Endcover ass’y.