JLG 40H Service Manual - Manual (Page 124)

SECTION 3 - TROUBLESHOOTING
3-12
– JLG Lift – 3120240
TROUBLE PROBABLE CAUSE REMEDY
STEERING SYSTEM.
No response to control. Circuit breaker open.
If equipped, steer/tow selector in “tow” position.
Hydraulic system oil low.
Hydraulic system pressure too low.
Damaged wiring on control switch or solenoid valve.
Control switch not functioning properly.
Restricted or broken hydraulic line on valve bank,
hydraulic pump or rotary coupling.
Swivel coupling leaking internally. (Seal(s) defec-
tive.)
Control valve not functioning properly.
Steer cylinder not functioning properly.
Determine and correct cause; reset circuit breaker.
Actuate control to “steer” position. (Valve knob “in”.)
Replenish oil as necessary.
Adjust pressure.
See proper wiring diagram.
Replace switch.
Clean, repair or replace line.
Repair or replace coupling.
Repair or replace valve.
Repair or replace cylinder.
Machine hard to steer or steering is erratic. Hydraulic system oil low.
Restricted hydraulic line or fitting.
Lack of lubrication.
Restricted crossover relief valve.
Steer system pressure low.
Bent linkage (tie rod(s) or steering hitch.)
Hydraulic pump not functioning properly.
Steer cylinder not functioning properly.
Spindle pins tight or need lubrication.
Replenish oil as necessary.
Clean,repair or replace line or fitting.
Lubricate as required. (Refer to Lubrication Chart.)
Clean or replace valve.
Adjust pressure.
Repair or replace linkage as required.
Repair or replace pump.
Repair or replace cylinder.
Repair or lubricate spindles.