What Is a Brake Pot?

Researching the specifications of new and used cars online can be confusing to the layman. When reading about disc brakes, terms like "caliper," "rotor" and "pad" are defined easily enough--but what is a "pot?"

The answer is deceptively simple. When discussing disc brakes, "pot" is simply car-guy speak for "piston." The shortened term is most often used when discussing brake specifications: a four-piston brake caliper will be referred to as a "four-pot" caliper.

Disc brakes work by pressing a high-friction material against a disc that is attached to the rotor. Though mechanically complex, the system itself consists of four major components: the rotor, pad, piston (or "pot," if you prefer) and caliper. The rotor is the disc that's attached to the axle. The pads press against the rotor on either side, like a clamp, and the piston is what pushes the pad against the rotor. The caliper wraps around part of the rotor in a C-shape, and is the unit that contains the pads, pistons and compression mechanism, which can be hydraulic, electronic or a combination of both.

The number of pistons can vary depending on the application. High-performance automobiles often use multiple pistons to provide additional brake clamping force.