Ford Mustang/Capri 1979-1988 Repair Guide

Wheel Cylinders



See Figures 1, 2 and 3

  1. Remove the brake shoes, as described above.
  3. Disconnect the brake line at the rear of the cylinder, but do not pull the line away from the cylinder, or it may bend.
  5. Remove the bolts and lockwashers that attach the wheel cylinder to the backing plate and remove the cylinder.

To install:
  1. Position the new or overhauled wheel cylinder on the backing plate, and install the cylinder attaching bolts and lockwashers.
  3. Attach the metal brake line or rubber hose by reversing the procedure given in Step 2.
  5. Install the brake shoes, as described above.
  7. Bleed the brake system and centralize the pressure differential valve, as detailed earlier in this section.

Click image to see an enlarged view

Fig. Fig. 1: Using a wrench, unscrew the brake line at the rear of the backing plate

Click image to see an enlarged view

Fig. Fig. 2: With a socket, unfasten the wheel cylinder retaining bolts

Click image to see an enlarged view

Fig. Fig. 3: Remove the wheel cylinder from the backing plate


See Figures 4, 5 and 6

Since the travel of the pistons in the wheel cylinder changes when new brakes shoes are installed, it is possible for previously good wheel cylinders to start leaking after new brakes are installed, Therefore, to save yourself the expense of having to replace new brakes that become saturated with brake fluid, and the aggravation of having to take everything apart again, it is strongly recommended that wheel cylinders be rebuilt every time new brake shoes are installed. This is especially true on high mileage cars.

  1. Remove the brakes.

Brake shoes contain asbestos, which has been determined to be a cancer causing agent. Never clean the brake surfaces with compressed air! Avoid inhaling any dust from any brake surface! When cleaning brake surfaces, use a commercially available brake cleaning fluid.

  1. Place a bucket or old newspapers under the brake backing plate to catch the brake fluid that will run out of the wheel cylinder.
  3. Remove the boots from the ends of the wheel cylinders.
  5. Push one piston toward the center of the cylinder to force the opposite piston and cup out of the other end of the cylinder. Reach in the open end of the cylinder, and push the spring cup and piston out of the cylinder.
  7. Remove the bleeder screw from the rear of the cylinder, behind the backing plate.
  9. Inspect the inside of the wheel cylinder. If it is scored in any way, the cylinder must be honed with a wheel cylinder hone or fine emery paper. Finish with crocus cloth, if emery paper is used. If the inside of the cylinder is excessively worn, the cylinder will have to be replaced, as only 0.003 in. (0.0762mm) of material can be removed from the cylinder walls. When honing or cleaning the wheel cylinders, keep a small amount of brake fluid in the cylinder to serve as a lubricant.
  11. Clean any foreign matter from the pistons. The sides of the pistons must be smooth for the wheel cylinders to operate properly.
  13. Clean the cylinder bore with alcohol and a lint-free rag. Pull the rag through the bore several times to remove all foreign matter and dry the cylinder.
  15. Install the bleeder screw and the return spring in the cylinder.
  17. Coat new cylinder cups with new brake fluid and install them in the cylinder. Make sure that they are square in the bore, or they will leak.
  19. Install the pistons in the cylinder after coating them with new brake fluid.
  21. Coat the insides of the boots with new brake fluid and install them on the cylinder.
  23. Install the wheel cylinder, as described above.

Click image to see an enlarged view

Fig. Fig. 4: Remove the rubber boot from each end of the wheel cylinder

Click image to see an enlarged view

Fig. Fig. 5: If necessary, compressed air can be used to dislodge the pistons and cylinder cups

Click image to see an enlarged view

Fig. Fig. 6: A wheel cylinder contains these replaceable parts