push rod forward (see Figure 90-1). The push rod is con-
BRAKE CHAMBER (1038Z170)
nected to a wedge assembly which forces two plungers
DESCRIPTION. Two of these brake chambers are used at
apart when the wedge is forced between the plungers by the
each front wheel. The purpose of brake chambers in an air
push rod. This spreads the plungers apart, pushing the brake
brake system is to convert compressed air energy into
shoes outward to apply the brakes.
mechanical force and movement, which applies the vehicle
When air pressure is vented from the brake chamber, the
wedge spring returns the wedge and diaphragm to their re-
Air pressure enters the pressure side of the brake chamber
leased position, releasing the brakes.
and forces against the diaphragm, which in turn moves the
Figure 90-1. Front Brake Mechanism