Power brakes are a system of hydraulics used to slow down or stop most motor vehicles. It uses a combination of mechanical components to multiply the force applied to the brake pedal by the driver into enough force to actuate the brakes and stop a vehicle that can weigh several tons. The brake pedal is connected to the vacuum booster which is the first step of the force multiplication. The booster passes the force to the master cylinder, which applies a compressive force to a liquid (hydraulic or brake fluid) and forces it through the brake lines to the brake calipers. The liquid pushes the brake calipers, which in the case of disc brakes, push against the brake rotor causing friction that slows and eventually stops the rotation of the vehicles wheels. In drum brakes, pistons push two shoe