Disc Brake System: Description and Operation

SYSTEM OPERATION
The disc brake assembly consists of a caliper assembly, rotor and pads mounted to the steering knuckle. The caliper mounts in a way that allows it to move laterally against the rotor. The caliper is a one piece casting with the inboard side containing the piston bore. A square cut rubber seal fits in a groove in the piston bore to provide a hydraulic seal and return mechanism for the piston.

Application of the brake pedal causes hydraulic pressure to move the piston. The piston then forces the inboard brake pad against the inboard braking surface of the rotor. Increasing the force against the rotor causes the caliper assembly to move inboard. The outer brake pad then contacts the outboard braking surface of the rotor. The force of the two brake pads provides the desired clamping action on the rotor.

Releasing the brake pedal relieves the pressure applied to the piston. The square cut seal on the piston returns to its normal position, allowing a running clearance between the brake pads and rotor.