GM Service Manual Online
For 1990-2009 cars only

Caliper Assembly Components


Object Number: 470318  Size: MF
(1)Bleeder Plug Cap
(2)Bleeder Plug
(3)Caliper Bolt
(4)Caliper
(5)Caliper Slide Pin
(6)Caliper Slide Pin Boot
(7)Caliper Bracket
(8)Caliper Bracket Bolt
(9)Brake Pad Insulator
(10)Brake Pad
(11)Brake Pad Retainer
(12)Brake Pad
(13)Brake Pad Insulator
(14)Brake Pad Retainer
(15)Caliper Piston Boot
(16)Caliper Piston Seal
(17)Caliper Piston

The caliper is a single bore, floating piston type. Pressure on the brake pedal increases the brake fluid pressure against the caliper piston. Pressure exerts equally at the following locations:

    • Against the bottom of the piston.
    • Against the bottom of the piston bore.

The pressure against the bottom of the piston transmits to the inboard brake pad, forcing the pad against the inside of the rotor surface. The pressure against 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. As the pressure builds, the pads press against the rotor with increasing friction, bringing the vehicle to a stop.

Releasing the pressure on the brake pedal releases the fluid pressure. The piston and the pads retract from the rotor slightly, lessening the pad to rotor friction. This allows the wheel to turn again. The piston rubber seal keeps the clearance at a minimum at all times. When hydraulic pressure releases from the piston, a restoring force generates at the seal and pushes back the piston in order to prevent brake drag.

The following actions automatically compensate for pad wear:

    • Outward movement of the piston
    • Inward movement of the caliper

As the pads wear down, the increased area behind the piston is filled with brake fluid from the master cylinder reservoir.

Caliper Bracket

The caliper mounts to a caliper bracket by sliding pins. The caliper bracket bolts to the steering knuckle.

Rotor

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