Service Manual

SECTION 6 - TROUBLESHOOTING
3121231 – JLG Lift – 6-41
Mast Noisy When Lifting And Lowering
Overview Of Procedure
This procedure examines components of the mast itself and as well as it’s lifting components for dirt, debris, proper lubrica-
tion and operation.
Table 6-46. Mast Noisy when Lifting and Lowering.
STEP ACTION SPEC YES NO
1. Do slide pads and slide pad channels need to be cleaned of dust, dirt, or
other debris?
— Clean Pads and
Channels
Go to Step 2
2. Do mast chains need to be lubricated per JLG specification in the Service
Manual?
— Lubricate as
Required
Go to Step 3
3. Are the chain/cable sheave wheels dry and need lubrication?
Note: Plastic wheels will howl on the sheave pin when they are dry. Sheave
wheels may seize to the sheave pin and the pin may turn in the pin retainer
blocks.
— Lubricate or
Replace Sheave
Pins and Wheels
Go to Step 4
4. Are the sequence cables (located on the side of mast) chattering when the
springs are compressed?
Note: This noise is normal at the sequence cable sheave wheels when the
mast is completely lowered. However if the sequence cable chattering is
happening no matter what position the mast is i n, i t co uld be a res ult of t he
mast being shimmed to tight or dirt and debris in the slide pad channels
causing the mast to be tight.
—Clean Slide Pads/
Channels or Re-
shim Mast per Ser-
vice Manual
Go to Step 5
5. Is the bore of the lift cylinder dry? — Replace Packing or
Lift Cylinder
Go to Step 6
6. Are the bearings in the lift pump motor and pump drive worn? — Repair or Replace
Pump
Go to Step 7
7. Are the hydraulic lines vibrating together? — Adjust the Position
of the Lines
Go to Step 8
8. Check if the pump motor is loose to it’s mounting plate. — Tighten pump
mounting
fasteners
Go to Step 9
9. Hydraulic oil could be cavatating inside the pump. — Repair or Replace
Pump
—