The brake caliper is a heavy metal housing that mounts over the brake rotor and contains one or more hydraulic pistons. When the driver presses the brake pedal, brake fluid forces the pistons outward, clamping the brake pads tightly against the spinning rotor to create friction and stop the vehicle. Calipers can be fixed in place with pistons on both sides, or floating with pistons on just one side.
The right front caliper is seized up completely, which is why your steering wheel shakes when you brake.
A stuck caliper pin is the most common cause of uneven brake pad wear. Always grease the slide pins during a brake job.
Do not mix it up with
- Brake shoe: Calipers squeeze pads against a disc, while brake shoes expand outward against a drum.
Related terms
Disc brake
A braking mechanism that uses calipers to squeeze friction pads against a rotating rotor.
Brake assembly
A complete, pre-assembled unit containing the components needed to replace a vehicle's braking mechanism.
Brake fade
The loss of stopping power caused by excessive heat buildup in the braking system.