Truck must be on level ground and wheels
must be chocked before parking brake is
released. Otherwise, truck may roll and
cause injury to personnel.
Wear safety goggles when performing leakage
tests on valves. Failure to do so may
result in serious eye injury due to high
(1) Release PARKING BRAKE
(2) Listen to air chamber while
assistant applies then releases
(a) If mechanic cannot hear air
chamber operate when the brake
is applied and released, replace
air chamber (Para 12-10).
(b) If air chamber operates
correctly, go to Step 5 of this
(1) Apply service brakes
(2) Measure gap between brake shoe and
drum (Para 12-2).
(a) If there is no gap, perform Steps
(3) through (7) below.
(b) If there is a gap, adjust brakes
(3) Release service brakes.
(4) Cage air chamber (Para 12-10).
(5) Remove brake drum and air
chamber (Para 13-3 and 12-10).
(6) Inspect brake shoes and wedges
(a) If brake shoes and/or wedges are
faulty, replace brake shoes and/or
wedges (Para 12-2).
(b) If shoes and wedges are OK,
notify DS Maintenance.
(7) Install brake drum and air chamber
(Para 13-3 and 12-10).