The brake wheel cylinder, found on the rear of some modern vehicles, is part of the braking system. It turns hydraulic pressure form the master cylinder into mechanical movement which pushes the brake shoes against the brake drums slowing the vehicle. A brake wheel cylinder replacement is often needed when, over time, the wheel cylinders deteriorate and lose the ability to contain brake pressure
When performing a brake wheel cylinder replacement, the technician removes the wheel and brake drum. Then the brake shoes and all the hardware are removed. The old brake wheel cylinder is replaced with the new one and the brake components are reinstalled. Then brake fluid is added. The brake pedal is then applied continuously, which forces fresh fluid out to each wheel. The pressure forces open a brake "bleeder screw" at each wheel. The brake pedal is continually pressed until fresh brake fluid exits from all the wheels.
Some manufacturer factory warranties cover the cost of a brake wheel cylinder replacement under their bumper-to-bumper coverage if the wheel cylinder fails due to a manufacturer defect or workmanship. An extended auto warranty is an option available that will extend coverage of the brake wheel cylinder, depending upon the amount of coverage selected, past the manufacturer factory warranty's expiration.