SAAB WIS ONLINE

Brake caliper, front

Brake caliper, front


Each brake caliper consists of a hydraulic body with a brake piston and two brake pads and also a bracket. The hydraulic body is mobile and slides over two guide pins when fitted on the bracket. The guide pins are stainless steel and should not be lubricated.

The hydraulic body has a piston with two grooves that give lesser contact surface to the brake pads and better cooling for the piston. This design gives a little heat distribution to the brake fluid. The brakes can therefore tolerate a high thermal load. It is important that the brake piston is fitting in the correct position after removal, so the right cooling is achieved (see “Fitting front brake piston”).

When the brake is operated the hydraulic pressure acts partly straight to the brake cylinder and partly against the brake cylinder walls. The brake piston forces the inner brake shoes against the brake disc. Meanwhile the hydraulic body slides across so that the brake shoes press against the brake disc. When the hydraulic pressure ceases the brake piston in each brake cylinder returns to the brake off position with the aid of the piston seal.