Rear Disc Brakes

Fig. 1 Disassembled View Of AC-Delco Single Piston Rear Disc Brake Caliper. Type 2.:

DESCRIPTION
The caliper assembly, Fig. 1, has a single bore and is mounted to the support bracket with two mounting bolt and sleeve assemblies. Hydraulic pressure created by applying the brake pedal, is converted by the caliper to a stopping force. This force acts equally against the piston and the bottom of the piston bore to move the piston outward and to slide the caliper inward resulting in a clamping action. This clamping action presses the linings against the rotor, creating friction to stop the vehicle.

When the parking brake is applied, the external caliper parking brake lever moves and rotates a spindle within the caliper housing. As the spindle rotates, a connecting rod is pushed against an internal adjusting screw which is threaded into a sleeve nut in the piston assembly. This causes the piston assembly to move outward bringing the inboard shoe and lining assembly against the rotor. As the inboard shoe and lining contacts the rotor, a reaction force causes the caliper housing to slide inward pressing the outboard shoe and lining against the rotor.

OPERATION
The piston assembly contains a self adjusting mechanism to keep the parking brake in proper adjustment. As the linings are worn, the piston moves through the seal to maintain proper lining to rotor clearance. The park brake adjusts to proper clearances through an internal sleeve nut that rotates and moves as one unit with the piston.