What Is a Brake Caliper ？

Update time:2022-07-12

If your car is equipped with disc brakes, brake calipers are essential for slowing down and stopping the car. Here's what you need to know.

The brake caliper plays a central role in a disc brake system, serving two functions. First, it can be used either as a bracket to support the brake pads on either side of the rotor, or to support the caliper bracket itself - there are other designs, but these are the two most common. Second, it uses pistons to convert the pressure the master cylinder puts on the brake fluid into friction on the rotors.

In simple terms, the job of a brake caliper is to squeeze the brake pads against the rotors to stop the car. There are two main types of calipers, single-piston and dual-piston. Most front calipers are dual-piston, but many cars use single-piston calipers at the rear, requiring less stopping power.

Depressing the brake pedal forces the master cylinder piston forward, compressing the brake fluid. The brake fluid forces the caliper pistons towards the rotors, sandwiching the rotors between the brake pads, which creates friction and slows the vehicle.

When the brake caliper is broken

Generally speaking, brake pads and rotors wear out and need to be replaced more frequently than calipers. However, the main cause of damaged calipers is driving the vehicle on worn brake pads or twisted rotors. Both prevent the system from dissipating frictional heat, as they are designed to do, which can damage the calipers.

If the brake pads fail to protect the calipers from overheating, the pistons can be damaged, or heat can be transferred through the pistons to the brake fluid, causing the brake fluid to degrade. The latter can cause the brakes to fail.

A damaged piston, or just one that is corroded, can get stuck in one place. If it stays in the retracted position, that wheel will lose its braking ability. If it stays in the engaged position, the wheel will continue to brake until released.