202 Auto Brakes
Figure 12-20. An exploded view of a rear disc brake assembly which uses a set of drum brakes for parking. The parking brake
cable will force the brake shoes into contact with the drum section located inside the rotor hub. (Toyota)
Parking brake
cable
Backing plate
Pin
Drive axle
Splash shield
Shoe
strut
Disc
(rotor)
Plug
Parking brake
drum inside
of hub
Rear disc brake
caliper assembly
Shoe return spring
Parking brake shoe lever
Shim
C-washer
Spring Guide
plate
Front
shoe
Adjuster
Tension
spring
Shoe
hold-down
cap
Shoe
hold-down
spring
Rear
shoe
Figure 12-19. A cutaway view of a ball-and-ramp parking brake
assembly and clamp unit.
Balls
Operating
shaft
Lever
Caliper
Piston
Adjuster is part of
piston assembly
Thrust screw
Rear disc brakes must have a provision for a parking
brake. This brake can be an internal device which applies
the pads, Figure 12-19, or a separate set of small shoes,
Figure 12-20.
Rear Caliper Construction
There are three caliper designs used on rear brakes.
They are the screw type, which uses an integrated screw
to actuate the parking brake. The second is the ball-and-
ramp, which contains three steel balls between a shaft and
screw mechanism. The third is the cam-type that uses a
lever operated cam. Information on each of these can also
be found in Chapters 6 and 18.
Disc Brake Pads
The disc brake pads are designed to create friction
when forced into contact with the spinning rotor during
braking. The disc brake pad consists of a lining (the actu-
al brake material) and a shoe (the metal lining support),
Figure 12-21. The lining is designed to give the best