What is a wheel cylinder?

A wheel cylinder is a component found in a drum brake system of a vehicle. It is responsible for the hydraulic clamping force that applies pressure to the brake shoes against the drum to slow or stop the vehicle. The wheel cylinder consists of a cylinder body and a piston. When the brake pedal is applied, the master cylinder sends hydraulic fluid to the wheel cylinder, which pushes the piston outwards, causing the brake shoes to move towards the drum. This movement generates friction, thus slowing down the vehicle. The wheel cylinder is typically located at the top of the drum brake assembly and has a rubber boot to prevent dust and dirt from contaminating the brake fluid. Over time, the wheel cylinder may wear out or become damaged and may require replacement.