Jeep Wagoneer/Commando/Cherokee 1984-1998

Brake Rotor

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Removal & Installation



Front
4-WHEEL DRIVE

See Figures 1 and 2

  1. Loosen the lug nuts on the front wheels.
  2.  
  3. Raise and support the vehicle safely.
  4.  
  5. Remove the front wheels.
  6.  
  7. Remove the calipers, but don't disconnect the brake lines. Suspend the calipers out of the way.
  8.  
  9. Remove the rotor.
  10.  
  11. Installation is the reverse of removal. Tighten wheel lug nuts to 75 ft. lbs. (101 Nm).
  12.  



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Fig. Fig. 1: Removing the brake rotor



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Fig. Fig. 2: Exploded view of the rotor and hub assembly used on 4WD vehicles

2-WHEEL DRIVE

See Figure 3

  1. Raise and safely support the front end on jackstands.
  2.  
  3. Remove the wheels.
  4.  
  5. Remove the caliper without disconnecting the brake line. Suspend it out of the way. Refer to the caliper removal procedure in this section.
  6.  
  7. Remove the grease cap, cotter pin, nut cap, nut, and washer from the spindle.
  8.  
  9. Pull slowly on the hub and catch the outer bearing as it falls.
  10.  
  11. Remove the hub and rotor. The inner bearing and seal can be removed by prying out and discarding the inner seal.
  12.  

To install:
  1. Clean and repack the hub and bearings, install the inner bearing and a new seal.
  2.  
  3. Position the hub and rotor on the spindle and install the outer bearing.
  4.  
  5. Install the washer and nut.
  6.  
  7. While turning the rotor, tighten the nut to 25 ft. lbs. (33 Nm) to seat the bearings.
  8.  
  9. Back off the nut 1 / 2 turn, and, while turning the rotor, tighten the nut to 19 inch lbs. (2 Nm).
  10.  
  11. Install the nut cap and a new cotter pin. Install the grease cap.
  12.  
  13. Install the caliper.
  14.  
  15. Install the wheels.
  16.  



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Fig. Fig. 3: Exploded view of the rotor and hub assembly used on 2WD vehicles

Rear

CAUTION
Brake shoes may contain asbestos, which has been determined to be a cancer causing agent. Never clean the brake surfaces with compressed air! Avoid inhaling any dust from any brake surface! When cleaning brake surfaces, use a commercially available brake cleaning fluid.

  1. Loosen the lug nuts on the rear wheels.
  2.  
  3. Raise and support the vehicle safely.
  4.  
  5. Remove the rear wheels.
  6.  
  7. Remove the calipers, but don't disconnect the brake lines. Suspend the calipers out of the way.
  8.  
  9. If equipped, remove and discard the push nuts securing the rotor to the wheel studs.
  10.  
  11. If the rotor and/or axle hub contact surfaces appear to have heavy rust, apply a rust penetrating oil to those surfaces as well as through the spaces around the wheel studs. If necessary, use a plastic or rawhide mallet to loosen the rotor.
  12.  
  13. Remove the rotor. If necessary, remove the access plug from the splash shield and back off the parking brake shoes enough to allow removal of the rotor .
  14.  
  15. Installation is the reverse of removal. Tighten wheel lug nuts to 75 ft. lbs. (101 Nm).
  16.  

INSPECTION



See Figures 4 and 5

This inspection procedure also applies to the rear brake rotors.

Check the rotor for surface cracks, nicks, broken cooling fins and scoring of both contact surfaces. Some scoring of the surfaces may occur during normal use. Scoring that is 0.015 in. (0.38mm) deep or less is not detrimental to the operation of the brakes.

If the rotor surface is heavily rusted or scaled, clean both surfaces on a disc brake lathe using flat sanding discs before attempting any measurements.

With the rotor assembly mounted on the vehicle or a disc brake lathe and all play removed from the wheel bearings (front), assemble a dial indicator so that the stem contacts the center of the rotor braking surface. Zero the dial indicator before taking any measurements. Lateral run-out must not exceed 0.005 in. (0.13mm) with a maximum rate of change not to exceed 0.001 in. (0.025mm) in 30° of rotation.

Excessive run-out will cause the rotor to wobble and knock the piston back into the caliper, causing increased pedal travel, noise and vibration.

Check the Brake Specifications Chart for rotor thickness. Discard the rotor if it is not within the specification.

Remember to adjust the preload on the wheel bearings after the run-out measurement has been taken.



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Fig. Fig. 4: Measuring the rotor thickness with a micrometer



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Fig. Fig. 5: Checking the rotor lateral run-out with a dial indicator

 
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