JLG 150HAX ANSI Service Manual - Manual (Page 142)

SECTION 6 - SCHEMATICS
6-14 – JLG Lift – 3120679
Machine hard to steer or steering is erratic.
Hydraulic system oil low. Replenish oil as necessary.
Restricted hydraulic line or fitting. Clean, repair or replace line or fitting.
Lack of lubrication. Lubricate as required. (Refer to
Lubrication Chart.)
Restricted crossover relief valve. Clean or replace valve.
Steer system pressure low. Adjust pressure.
Bent linkage (tie rod(s) or steering hitch). Repair or replace linkage as required.
Hydraulic pump not functioning
properly. Repair or replace pump.
Steer cylinder not functioning properly. Repair or replace cylinder.
King pins and bushings worn. Replace king pins and bushings.
Steering inoperative.
Circuit breaker open. Determine and correct cause; reset circuit
breaker.
Damaged wiring on control switch/ controller or
solenoid valve. See proper wiring diagram.
Solenoid valve not functioning properly. Repair or replace valve.
Control switch/controller not functioning prop-
erly. Replace switch/controller.
Relief valve improperly set or not functioning
properly. Reset, repair or replace valves as
required.
Steer cylinder not functioning properly. Repair or replace cylinder.
Machine will not steer left or to the right.
Wiring on control switch/controller is
damaged. Repair or replace wiring.
Wiring on solenoid valve damaged. Repair or replace wiring.
Coil in solenoid damaged. Replace coil.
No oil flow or pressure to steer circuit. Take pressure reading at steer valve and adjust
as necessary.
Bent cylinder rod. Repair or replace cylinder.
Damaged tie rod. Replace tie rod.
Crossover relief valve sticking. Repair crossover relief valve.
Table 6-4.Chassis - Troubleshooting
TROUBLE PROBABLE CAUSE REMEDY