Self Adjusting Mechanism; Parking Brake; General Maintenance - JLG T500J Service And Maintenance Manual

SECTION 3 - CHASSIS & TURNTABLE

Self Adjusting Mechanism

The self adjusting feature adjusts the brakes on both forward
and reverse stops. Brake adjustment occurs only when lining
wear results in enough gap between the shoes and the drum
surface. The added clearance allows the adjuster mechanism
to rotate the screw assembly at the bottom of the brake. That
action expands the distance between the shoes and thus
closes the gap to the drum surface.

Parking Brake

The parking brake is cable operated. The parking cable body is
mounted to the brake backing plate. The cable end is attached
to the internal parking brake lever to actuate the brake. The
internal parking brake lever, which is mounted to the second-
ary shoe, transfers applied cable force through a parking strut
which is attached to the primary shoe. This transferred load
generates a spreading force between the primary and second-
ary shoes. The shoes move toward the drum until contact is
made. Friction generated between the drum and lining con-
tact surface results in parking brake capablilty.
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General Maintenance

DRUM BRAKE ADJUSTMENT
Brakes should be adjusted (1) after the first 200 miles of opera-
tion when the brake shoes and drums have "seated, " (2) at
3000 miles intervals, (3) or as used and performance requires.
The brakes should be adjusted in the following manner:
DO NOT LIFT OR SUPPORT THE TRAILER ON ANY PART OF THE AXLE OR SUS-
PENSION SYSTEM. NEVER GO UNDER ANY TRAILER UNLESS IT IS PROPERLY
SUPPORTED ON JACK STANDS WHICH HAVE BEEN RATED FOR THE LOAD.
IMPROPERLY SUPPORTED VEHICLES CAN FALL UNEXPECTEDLY AND CAUSE
SERIOUS INJURY OR DEATH.
1. Jack up trailer and secure on adequate capacity jack
stands. check that the wheel and drum rotate freely.
2. Remove the adjusting hole cover from the adjusting slot
on the bottom of the brake backing plate.
3. With a screwdriver or standard adjusting tool, rotate the
starwheel of the adjuster assembly to expand the brake
shoes. Adjust the brake shoes out until the pressure of
the linings against the drum makes the wheel very diffi-
cult to turn.
4. Rotate the starwheel in the opposite direction until the
wheel turns freely with a slight lining drag.
5. Replace the adjusting hole cove and lower the wheel to
the ground.
6. Repeat the above procedure on all brakes. For best
results, the brakes should all be set at the same clear-
ance.
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