JLG 45e Service Manual User Manual
Page 78
SECTION 3 - TROUBLESHOOTING
3-4
– JLG Lift –
3120861
Table 3-2.BOOM ASSEMBLY - TROUBLESHOOTING
TROUBLESHOOTING CHART
TROUBLE
PROBABLE CAUSE
REMEDY
BOOM ELEVATION SYSTEM (CONTINUED).
Boom will not raise.
Load capacity exceeded (personnel or equipment
on platform).
Reduce load.(Refer to capacity placard.)
Hydraulic system oil low.
Replenish oil as necessary.
Electrical failure to valves.
See proper wiring diagram.
Restricted or broken hydraulic line or fitting.
Clean, repair, or replace line or fitting.
Control valve not functioning properly.
Repair or replace valve.
Pressure relief valve not functioning properly.
Re-adjust or replace valve.
Bypass valve (dump) not functioning.
Repair or replace valve.
Lift cylinder not functioning properly.
Repair or replace cylinder.
Motor/Pump does not respond when LIFT control
switch is moved to UP position.
Refer to Electrical Diagram and/or Electrical Sys-
tem Troubleshooting Chart.
Binding lift cylinder or boom pivot pin.
Repair or replace cylinder or pin.
Boom will not lower.
See: Boom will not raise.
Pressure relief valve not functioning properly.
Re-adjust or replace valve.
Holding valve not functioning properly.
Re-adjust or replace valve.
Boom raises and lowers erratically.
Hydraulic system oil low.
Replenish oil as required.
Restricted or broken hydraulic line or fitting.
Clean, repair, or replace line or fitting.
Lack of lubricant on cylinder shafts and/or boom
pivot.
Lubricate as required.
(Refer to Lubrication Chart.)
Counterbalance valve on lift cylinder improperly
adjusted or not functioning properly.
Replace valve.
Control valve not functioning properly.
Repair or replace valve.
Worn seals in lift cylinder.
Replace seals.
Cylinder not functioning properly.
Repair or replace cylinder.
Boom drifts down.
Worn seals in lift cylinder.
Replace seals.