It is the force of the Ford drum brake wheel cylinder that applies the pressure so the brake shoes making contact with the drums is sufficient to bring your vehicle to a stop. This is the counter part to the brake calipers used on disc brakes. The location of the drum brake wheel cylinder is on the upper center portion of the backing plate of a drum brake system on Ford models. Hydraulic fluid is held inside this component by seals or cups, and when compressed it pushes two pistons outward from the ends. These seals are made out of a polymer and are the pieces that will wear out in time causing a brake fluid leak. Evidence of this can be noticed when there is brake fluid on the payment where the inside of the rear tires were located when the vehicle was parked. The replacement of the Ford drum brake wheel cylinder can be accomplished by the car or truck owner very easily, just as long as they know how to do a brake job. Once the drum and shoes are taken off of the backing plate, the drum brake wheel cylinder can be removed from your Ford car or truck. Before the mounting bolts are removed, the rear brake line should be loosened and removed. Since this component has been in place for a considerable amount of time, it might be stubborn. Take care in its removal or you will also be replacing this brake line if it is damaged. With the new drum brake wheel cylinder in place on your Ford, the brake shoes are them mounted and the drum placed on the wheel. The drum brake wheel cylinder must then be bled of air by opening the nipple on it when pressure is being applied to the system.