GM Service Manual Online
For 1990-2009 cars only

Rotor

The rotor is a highly-machined cast iron, ventilated type.

Caliper

The caliper is a single bore, floating piston type. The caliper is mounted to a caliper carrier by sliding pins. The caliper carrier is bolted to the steering knuckle.

When the brake pedal is pressed, fluid pressure behind the caliper piston increases. Pressure is exerted equally against the bottom of the piston bore. The pressure applied to the piston is transmitted to the inboard brake pad, forcing the pad against the inside of the rotor surface. The pressure applied to the bottom of the piston bore forces the caliper to slide on the mounting bolts toward the center of the vehicle. This movement causes the outer section of the caliper to apply pressure against the back of the outboard brake pad, forcing the pad against the outside of the rotor surface. As pressure builds, the pads are pressed against the rotor with increased force, bringing the vehicle to a stop.

When the brake pedal is released, fluid pressure is released and the piston and pads retract from the rotor slightly, lessening the pad to rotor drag and allowing the wheel to turn again. This clearance is kept to a minimum at all times by means of the piston rubber seal. When hydraulic pressure is released from the piston, a restoring force is generated at the seal and pushes the piston back in order to prevent brake drag.

Outward movement of the piston and inward movement of the caliper automatically compensate for pad wear. As pads wear down, the increased area behind the piston is filled with the brake fluid from the master cylinder reservoir.

Caliper Carrier

The caliper is mounted to a caliper carrier by sliding pins. The caliper carrier is bolted to the steering knuckle.