GM Chevy Mid-Size Cars 1964-1988 Repair Guide

Brake Disc

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INSPECTION



See Figures 1 and 2

  1. Tighten the spindle nut to remove all wheel bearing play.
  2.  
  3. Install a dial indicator on the caliper so that its feeler will contact the disc about 1 in. (25.4mm) below its outer edge.
  4.  
  5. Turn the disc and observe the runout reading. If the reading exceeds 0.002 in. (0.051mm) for 1970-83 vehicles or 0.004 in. (0.102mm) for other years, the disc should be replaced.
  6.  
  7. Measure the thickness of the rotor at 5 points around the circumference. The tolerance for difference in thickness is 0.005 in. (0.127mm).
  8.  
  9. Minimum thickness dimensions are cast into the caliper for reference.
  10.  



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Fig. Fig. 1: Use a dial indicator to measure brake disc runout



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Fig. Fig. 2: A discard dimension (in this case 0.965 in.) is stamped onto most brake disc hubs

REMOVAL & INSTALLATION



See Figure 3

On some older vehicles covered in this guide, the original brake discs may be separated from the hubs by drilling out the attaching rivets. Before attempting this, check with your local parts supply store to see if replacement hubs or discs are available. In most cases, the entire assembly will have to be replaced.

  1. Raise and support the front of the vehicle safely using jackstands.
  2.  
  3. Remove the tire and wheel assembly.
  4.  
  5. Remove the brake caliper from the mounting bracket and wire it out of the way. Be sure not to stretch and damage the brake hose.
  6.  
  7. Carefully pry out the grease cap, then remove the cotter pin, spindle nut and washer. Remove the hub and disc from the spindle being careful not to drop the outer wheel bearings.
  8.  

To install:
  1. Carefully install the wheel hub over the spindle, making sure the outer bearing is in place.
  2.  
  3. Loosely install the spindle washer and nut, but do not install the cotter pin or dust cap at this time.
  4.  
  5. Remove the wire support, then install the brake caliper assembly.
  6.  
  7. Install the tire and wheel assembly.
  8.  
  9. Properly adjust the wheel bearings, then install a new cotter pin and the dust cap. For wheel bearing adjustment procedures, refer to Suspension & Steering of this guide.
  10.  
  11. Install the hub cap, then remove the supports and carefully lower the vehicle.
  12.  



Click image to see an enlarged view

Fig. Fig. 3: Exploded view of a common disc brake assembly

 
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