AMC Coupes/Sedans/Wagons 1975-1988 Repair Information

Brake Disc (Rotor)

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REMOVAL & INSTALLATION Except Eagle



See Figure 1

Click image to see an enlarged view

Fig. Fig. 1: After removing the caliper and brake pads, the brake rotor (disc) may be removed from the spindle

  1. Raise the front end and remove the wheel.
  2.  
  3. Remove the caliper and adapter assembly. Details are given earlier.
  4.  
  5. Wire the caliper to the suspension to prevent straining the brake line.
  6.  
  7. Remove the grease cap, cotter pin, nut, and washer front the wheel spindle.
  8.  
  9. Pull the disc out slightly and push it back. Remove the outer wheel bearing.
  10.  


WARNING
Keep your greasy hands off the disc surface!

  1. Remove the hub and disc.
  2.  
  3. Make sure that the grease in the hub is clean, that the wheel bearings are both packed with grease, and that the disc surfaces are clean.
  4.  


WARNING
Use only grease specified for disc brake use. Ordinary grease will melt and ooze all over the braking surfaces, ruining the friction pads.

  1. Slide the hub and disc onto the spindle.
  2.  
  3. Install the outer bearing, washer, and nut. Adjust the wheel bearings as described later in this section. Install the cotter pin.
  4.  
  5. Clean the grease cap and coat the inside with grease. Don't pack it full. Install it.
  6.  
  7. Replace the caliper.
  8.  
  9. On replacing the wheel, torque the nuts to 75 ft. lbs.
  10.  

You may feel a little silly torquing wheel nuts, but this is important to prevent distorting the disc.

Eagle

  1. Loosen the wheel retaining nuts.
  2.  
  3. Raise and support the automobile.
  4.  
  5. Remove the front wheels.
  6.  
  7. Remove the caliper assembly but do not disconnect the brake line. Suspend the caliper from a wire hook attached to the front spring. Do not let the brake hose support the weight of the caliper.
  8.  
  9. Remove the rotor. Pull the rotor straight off of the hub.
  10.  
  11. Install the rotor on the hub.
  12.  
  13. Install the caliper.
  14.  
  15. Install the wheel. Tighten the wheel retaining nuts to 75 ft. lbs.
  16.  
  17. Lower the automobile.
  18.  


CAUTION
Check for a firm brake pedal and proper brake operation before moving the automobile.

INSPECTION



See Figures 2, 3 and 4

Click image to see an enlarged view

Fig. Fig. 2: Use a dial indicator to check the rotor lateral run-out



Click image to see an enlarged view

Fig. Fig. 3: Check that the hub-to-bore run-out is within specifications



Click image to see an enlarged view

Fig. Fig. 4: Use a micrometer on a few different positions to check the thickness variation of the rotor

The disc can be checked for runout (wobble) and thickness variations with a dial indicator and a micrometer while mounted on the car, or in a lathe. Runout should not exceed 0.005 in. (0.127mm) and thickness variation should not exceed 0.001 in. (0.025mm). The disc can be machined, but the final thickness must be at least 0.940 in. (23.876mm).

These are the factory's specifications; some state inspection laws aren't this lenient.

 
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