Ford Full-Size Cars 1968-1988 Repair Guide

Brake Disc (Rotor)


Brake pads may 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. Raise and safely support the vehicle. Remove the wheel and tire assembly.
  3. Remove the caliper, but do not disconnect the brake hose. Suspend the caliper inside the fender housing with a length of wire. Do not let the caliper hang by the brake hose.
  5. Remove the rotor retaining push nuts and remove the rotor from the hub.

If additional force is required to remove the rotor, apply penetrating oil to the rotor/flange mating surface. Install a suitable 3-jaw puller and remove the rotor. If excessive force must be used during rotor removal, the rotor should be checked for lateral run-out before reinstallation.

  1. Inspect the rotor for scoring and wear. Replace or machine as necessary. If machining, observe the minimum thickness specification.

To install:
  1. If the rotor is being replaced, remove the protective coating from the new rotor with brake cleaner. If the original rotor is being installed, make sure the rotor braking and mounting surfaces are clean.
  3. Install the rotor. The pushnuts do not have to be reinstalled.
  5. Install the caliper and the wheel and tire assembly. Lower the vehicle.
  7. Pump the brake pedal to position the brake pads, before moving the vehicle.
  9. Road test the vehicle.


Check the disc brake rotor for scoring, cracks or other damage. Check the minimum thickness and rotor run-out.

A brake pulsation that is present during brake application is caused by either foreign material build-up or contamination on the rotor braking surface or uneven rotor thickness. If there is a foreign material build-up or contamination found on the rotor or lining surfaces, hand sand the linings and rotors. Uneven rotor thickness (thickness variation) may be caused by: excessive run-out, caliper drag or the abrasive action of the brake lining. If brake pulsation is present, attempt stopping the vehicle with the transmission in the NEUTRAL position. If the pulsation is gone, the drivetrain should be inspected. If the pulsation remains, inspect the brakes.

Check the rotor thickness using a micrometer or calipers. The brake rotor minimum thickness must not be less than 0.44 in. (11mm).

Rotor run-out can be checked using a dial indicator. Mount the indicator to the brake adapter and position the indicator foot on the center of the braking surface. Rotate the rotor to check the run-out. Make sure there is no rust or foreign material between the rotor and axle flange. Hold the rotor to the axle flange by inverting the lugnuts and tightening them to 85-105 ft. lbs. (115-142 Nm). Rotor run-out must not exceed 0.003 in. (0.076mm).

If rotor run-out exceeds specification, the rotor can be repositioned on the axle flange to obtain the lowest possible run-out. If run-out remains excessive, machine the rotor if it will not be below the minimum thickness specification after machining.