Chassis Assembly Troubleshooting - JLG 40H Service And Maintenance Manual

TROUBLE
Valve spool sticking.
Valve leaking.
Strong fuel odor during machine
operation.
One or both front wheels will not steer.
One or both front wheels will not rotate or rotate
erratically.
Oscillating Axle will not hold properly.
3120240
Table 3-4. Chassis Assembly Troubleshooting.
PROBABLE CAUSE
CONTROL VALVES.
Dirt in oil causing excessive temperature build-up.
Incorrect valve mounting causing warping of the
unit.
Valve spool scored.
Return spring weak or broken.
Relief valve malfunctioning causing excessive
pressure within valve.
Dirt or other foreign material under seal.
Valve spool scored.
Excessive back pressure caused by restricted
return line to reservoir.
Damaged valve seal(s).
FUEL SYSTEM.
Fuel tank overfilled.
Fuel tank damaged.
Fuel line from tank damaged.
Filter or carburetor fuel leak.
FRONT FRAME AXLE AREA.
Steering link or tie rod broken or attaching hardware
missing.
Wheel hub or bearings damaged or not lubricated.
Hub attachment nut loose or missing.
Air in oscillating axle hydraulic system.
Cam Valve Stuck or leaking.
Lockout cylinder leaking.
– JLG Lift –
SECTION 3 - TROUBLESHOOTING
REMEDY
Change oil using recommended viscosity and flush
system.
Loosen valve and check mounting. Repair as nec-
essary.
Remove valve and repair or replace as necessary.
Remove valve and repair or replace as necessary.
Check pressure delivery to and from valve and
repair or replace as necessary.
Remove and repair valve as necessary.
Repair or replace valve.
Remove line and clean obstruction or replace line as
necessary.
Repair or replace valve as necessary.
Check fuel tank and immediately wipe up any spilled
fuel.
Drain all fuel from tank and remove tank for replace-
ment or repair.
Replace fuel line.
Determine cause of leak and make appropriate
repairs.
Replace steering link, tie rod or hardware as neces-
sary.
Replace hub or bearings as necessary and repack
bearings with approved grease.
Secure or replace hub attachment nut and cotter pin
as necessary.
See bleeding procedure in section 2.
Repair or replace cam valve.
Repair or replace cylinder.
3-9