REMOVAL & INSTALLATION
- Raise and safely support the vehicle.
- Remove the wheel and tire assembly.
- Remove the brake caliper and suspend it with wire from the coil spring; do not let the caliper hang from the brake hose.
- On 1990-91 Eldorado and Seville, remove the caliper mounting bracket mounting bolts and the mounting bracket.
- If equipped, remove the retainers from the wheel studs and discard; they do not have to be reinstalled.
- Remove the disc brake rotor. Inspect the rotor and machine or replace, as necessary.
- Install the disc brake rotor over the wheel studs and hub assembly.
- On 1990-91 Eldorado and Seville, install the caliper mounting bracket using new mounting bolts. Tighten the bolts to 83 ft. lbs. (112 Nm).
- Install the brake caliper.
- Install the wheel and tire assembly and lower the vehicle.
Inspect the rotor surface finish for discoloration due to overheating, excessive glazing or scoring. If the rotor is discolored or glazed, it must be machined. Light scoring of the rotor surface not exceeding a depth of 0.050 in. (1.2mm), which may result from normal use, is not detrimental to brake operation and refinishing is usually not necessary. Heavier scoring must be removed by refinishing, being careful to observe the minimum thickness specification.
Inspect the rotor for thickness variation. Excessive thickness variation can cause brake pedal pulsation or roughness during brake applications. Check thickness variation by measuring the rotor thickness using a micrometer at a minimum of 4 points around the circumference of the rotor. All measurements should be made at the same distance from the edge of the rotor. A rotor that varies more than 0.0005 in. (0.013mm) must be machined, being careful to observe the minimum thickness specification.
Inspect the rotor for excessive lateral runout. Excessive lateral, or side-to-side, runout of the rotor surface may cause vehicle vibration during braking. However, the vibration may not be felt through the brake pedal. Inspect for lateral runout as follows:
- Remove the wheel and tire assembly and reinstall the wheel lug nuts to hold the rotor on the hub and bearing assembly.
- Attach a dial indicator to the steering knuckle or caliper mounting bracket. Position the indicator foot so it contacts the rotor surface approximately 1 / 2 -1 in. from the rotor edge.
- Zero the dial indicator. Move the rotor one complete revolution and check the total indicated runout.
- If runout is excessive, in some instances it can be corrected by indexing the rotor on the hub one or two wheel stud positions from the original position.
- If the lateral runout cannot be corrected by indexing, check the hub and bearing assembly for excessive lateral runout or looseness. If the hub and bearing lateral runout exceeds 0.0015 in. (0.040mm) on Deville and Fleetwood, 0.004 in. (0.10mm) on 1990-91 Eldorado and Seville, or 0.002 in. (0.06mm) on 1992-98 Eldorado and Seville, replace the hub and bearing assembly and recheck rotor lateral runout.
- If the lateral runout still exceeds specification, machine the rotor, being careful to observe the minimum thickness specification.