Pontiac Fiero 1984-1988 Repair Guide

Brake Disc (Rotor)



  1. Raise the vehicle and support with jackstands.
  3. Remove the rear wheel assemblies.
  5. Remove the brake caliper and pads as outlined in the Brake Caliper and Pads procedures in this section.
  7. Remove the rotor assembly from the vehicle. If the rotor will not slide off the hub, tap the rotor with a plastic hammer to work loose. Also, spray some penetrating lubricant around the hub-to-rotor area.

To install:

  1. Position the rotor onto the hub.
  3. Install the caliper and brake pads as outlined in the Brake Caliper and Pads procedures in this section. 1988 models are different from the earlier models. Use the appropriate procedures.


Thickness Variation Check

The thickness variation can be checked by measuring the thickness of the rotor at four or more points. All of the measurements must be made at the same distance from the edge of the rotor. A rotor the varies by more than 0.0005 inch (0.013mm) can cause a pulsation in the brake pedal. If these measurement are excessive, the rotor should be refinished or replaced.

Lateral Run-out Check
  1. Remove the caliper and hang from the body with a piece of wire. Install two inverted lug nuts to retain the rotor.
  3. Install a dial indicator to the steering knuckle so that the indicator button contacts the rotor about 1 inch from the rotor edge.
  5. Zero the dial indicator.
  7. Move the rotor one complete revolution and observe the total indicated run-out.
  9. If the rotor run-out exceeds 0.0015 in. (0.040mm) have the rotor refinished or replaced.

Refinishing Brake Rotors

All brake rotors have a minimum thickness dimension cast onto them. Do not use a brake rotor that will not meet minimum thickness specifications in the Brake Specifications chart at the end of this section.

Accurate control of rotor tolerances is necessary for proper brake performance and safety. Machining of the rotor should be done by a qualified machine shop with the proper machining equipment.

The optimum speed for refinishing the rotor surface is a spindle speed of 200 rpm. Crossfeed for rough cutting should range from 0.010-0.006 in. (0.254-0.152mm) per revolution. The finish cuts should be made at crossfeeds no greater than 0.002 in. (0.051mm) per revolution.