JLG 20VP (3120849) Service Manual - Manual (Page 31)

SECTION 2 - SERVICE PROCEDURES
3120849 – JLG Lift – 2-13
Drive Motor Brush Replacement
Each drive motor contains two (2) brushes, the brushes
are located under the two (2) large round slotted brush
caps on the front end of each drive motor.
DISCONNECT THE POWER LEADS FROM THE POWER SOURCE
BEFORE INSPECTING OR REPLACING BRUSHES.
Brush Cleaning and Inspection
Brush wear rate varies depending on the individual appli-
cation’s duty cycle, and should be inspected at frequent
intervals to determine an appropriate inspection schedule.
Brushes should be replaced before they are less than .375
in. (9.5mm) in length. Carbon dust accumulation should
be removed periodically. If the end shield has been
removed from the drive, a clean, dry, non-linting cloth can
be used for cleaning. DO NOT use solvents as they my
damage non-metallic parts and adversely affect subse-
quent brush commutation.
Brush Removal (See Figure 2-12.)
Removal of the brushes also requires the removal of the
drive motor(s) from the machine, see procedure
described earlier in this section for instructions to remove
the drive motors. If not already done, disconnect the posi-
tive (+) battery cable from the left side battery before pro-
ceding.
1. Unscrew the large round brush caps from each side
of the drive motor, use as large a screw driver as
possible.
2. The brushes are retained by constant-force, roll-type
springs. To remove the springs, press inward on the
end of the spring retaining bracket using the tip of a
pair of long nose pliers or other appropriate tool.
The brushes should pop out, if not, they can be
removed by pulling outward on the spring brackets
with a pair of long nose pliers after the inside ends
are unhooked.
3. Now pull the brush out of the brush box by it’s wire
(pig-tail).
NOTE: If only inspecting the brushes, it is not necessary to
remove the pig-tail terminal from it’s connection to
the brush box.
4. Loosen the the screw securing the pig-tail terminal
end to the brush box and slide the terminal end out
from under the screw completely removing the
brush from the drive motor.
Figure 2-11. Drive Motor Brush Location.
BRUSH CAP
DRIVE MOTOR
BRAKE
ASSEMBLY
BRUSH CAP
BRUSH
ASSEMBLIES
LOCATED
INSIDE
HERE
Figure 2-12. Drive Motor Brush Installation.
BRUSH
BRUSH BOX
BRUSH BOX
INSULATOR
PIGTAIL WIRE
SPRING BRACKET
SPRING
BRACKET
HOOKS
SPRING BRACKET