Machine Won't Drive Straight - JLG 15MVL Series Service Maintenance Manual

SECTION 6 - TROUBLESHOOTING

Machine Won't Drive Straight

Overview Of Procedure
The following procedure examines the drive motor assembly weldments attaching the drive motors to the base frame. Also
internal components of the drive motors, gear box and a check of the components between the gear box and the drive
wheels.
Check For These Obvious Conditions First:
• Battery voltage 24 volts. (Fully charge batteries)
• Nothing is lodged between one of the wheels and the base frame.
• A caster wheel on the front of the machine is seized up, creating resistance.
STEP
1. Check for the following on the drive assembly, drive attachment weldments;
is bent, has broken welds, or loose hardware.
2. Check for the following on the drive assembly, drive motor mounting plates;
are bent, are square with drive weldments, or is hardware loose?
3. Check for the following on the drive assembly, drive motor hardware; is
hardware loose.
4. Check the left and right drive motor brakes for loose hardware & not releas-
ing properly.
5. Is the electrical signal and amperage draw to the drive motors equal? Check
with machine on level surface.
6. Check the drive motor brushes, do they need replaced?
7. Is joystick control defective?
If possible, swap out with another platform control.
8. Is the Traction Control Module defective or connections not tight?
If possible, swap out with another Traction Control Module.
9. Inside the drive motor gear box check if; the drive shaft is excessively loose
& condition of drive shaft bearings.
Are any gears broken or gear teeth excessively worn.
6-46
Table 6-54. Machine Won't Drive Straight.
ACTION
– JLG Lift –
SPEC YES
— Repair/Replace/
Tighten weldment
— Repair/Replace/
Tighten weldment
— Repair/Replace/
Tighten component
— Tighten or Adjust
per procedure
in this
Service Manual
See Table 6-3. Recheck Steps
1 thru 5
— Replace per
procedure in this
Service Manual
— Repair/Replace
Platform control
— Tighten Connec-
tions or Replace
Traction Control
Module
— Repair/Replace gear box
components per procedure in this Service
NO
Go to Step 2
Go to Step 3
Go to Step 4
Go to Step 5
Go to Step 6
Go to Step 7
Go to Step 8
Go to Step 9
Manual
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