A wheel brake cylinder is a part of a water hydraulic drum brake. The wheel cylinder must power separated the brake shoes and press them against the brake drum. This creates grating and the wheel is decelerated. This happens each time the driver pushes on the brake pedal. Pushing on the brake pedal creates a hydraulic liquid powered weight in the ace brake chamber which is communicated to the wheel brake cylinder in the brake liquid by means of the brake lines. In the wheel brake cylinder, the hydraulic liquid driven weight follows up on the cylinders, which at that point apply mechanical weight on the brake shoes.