Rear Disc Brakes

Operation of the rear disc brake is similar to the front disc brake during normal brake applications. As in the front brake system, fluid pressure behind the caliper piston is increased by applying the brake pedal. This fluid pressure is exerted equally against the piston and the bottom of the piston bore. When this pressure is applied, the piston is moved outward from the caliper and forces the inboard lining against the inner rotor surface. At the same time, the caliper slides inward on its mounting bolts, forcing the outboard lining against the outer rotor surface. As brake fluid pressure in the caliper piston bore increases, the shoe and lining assemblies are pressed against the rotor surface with increasing force, creating a frictional drag on the rotor which slows or stops the car. When fluid pressure is reduced (by releasing the brakes), the caliper piston seal and seal groove cause the piston to retract slightly, reducing the drag on the rotor. The rear brake calipers also contain a parking brake actuator mechanism which allows the rear brakes to be manually applied by the parking brake pedal. This mechanism consists of lever and screw configuration in which the screw threads act on a nut inside the caliper piston assembly. When the lever is turned by depressing the parking brake pedal, the screw turns and moves the piston outward from the caliper. When the piston moves outward, the caliper slides inward and the shoe and lining assemblies create a clamping force on the rotor.