Examine the disc. If it is worn, warped or scored, it must be replaced. Check the thickness of the disc against the specifications given in the Disc and Pad Specifications chart. If it is below specifications, replace it. Use a micrometer to measure the thickness.
The disc run-out should be measured before the disc is removed and again, after the disc is installed. Use a dial indicator mounted on a magnet type stand (attached to the shock absorber shaft) to determine runout. Position the dial so the stylus is 0.394 inch (10mm) from the outer edge of the rotor disc. The maximum allowable runout is 0.05 inch (0.20mm). If runout exceeds the specification, replace the disc.
Be sure that the wheel bearing nut is properly tightened. If it is not, an inaccurate run-out reading may be obtained. If different run-out readings are obtained with the same disc, between removal and installation, this is probably the cause.
Removal & Installation
- Remove the front wheel.
- Drain the brake fluid.
- Remove the union bolt and gasket from the disc brake cylinder and disconnect the flexible hose.
- Remove the front disc brake cylinder sub-assembly.
- Remove the disc brake pad kit.
- Remove the two front disc brake pad support plates from the cylinder mounting.
- Remove the two cylinder slide pins from the disc brake cylinder mounting.
- Remove the two bolts and the disc brake cylinder mounting.
- Remove the front disc.
- Immediately, matchmark the front disc to the axle hub.
- Installation is the reverse of removal.
- Torque the disc retaining bolts to 76 ft. lbs. (103 Nm).
- Loosen the wheel lugs, then raise and safely support the of the car. Remove the wheel(s) and temporarily attach the rotor disc with two bolts.
There are two spots to place bolts for retaining the rotor to the hub.
- Remove the caliper from the rotor and suspend on wire from the coil spring.
- Remove the two wheel bolts and pull the disc from the axle hub.
- Place the rotor into position and retain with the two bolts.
- Attach the caliper to the rotor.
- Remove the bolts from the rotor and install the wheel.
- Hand tighten the lug nuts, lower the vehicle and tighten the lug nuts.