Pontiac Fiero 1984-1988 Repair Guide

Wheel Hub/Rotor and Bearings

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REMOVAL & INSTALLATION





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Fig. Fig. 1 Use a prytool to remove the dust cap, then ...



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Fig. Fig. 2 ... remove the cotter pin using a pair of pliers



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Fig. Fig. 3 Remove the castellated nut from the spindle



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Fig. Fig. 4 Remove the washer, then ...



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Fig. Fig. 5 ... remove the bearing assembly from the hub

1984-87 Models

This procedure also includes repacking and adjustment of the wheel bearings.


CAUTION
Some brake pads 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. Raise the vehicle and support it safely with jackstands.
  2.  
  3. Remove the wheel and tire assembly.
  4.  
  5. Remove the brake caliper from the knuckle as outlined in the Brake Caliper procedure in this section.
  6.  
  7. Remove the dust cap, cotter pin, spindle nut and washer, and remove the hub and bearing.
  8.  

Do not allow the bearing to fall out of the hub when removing the hub from the spindle.

  1. Remove the outer bearing with your fingers, then remove the inner bearing by prying out the grease seal. Discard the seal.
  2.  
  3. Wash all removable parts thoroughly in cleaning solvent and dry with compressed air.
  4.  


WARNING
Do not wash the hub assembly in solvent. The solvent will penetrate the porous cast iron. After assembly, the solvent will cause the new grease to become liquid. Use clean paper or shop towels to clean out the old grease.

Only perform the next step if the bearing is going to be replaced with a new unit.

  1. If needed, drive out the old race from the hub with a brass drift inserted behind the race in the notches in the hub.
  2.  
  3. Lubricate the new race with a light film of high temperature grease, suitable for disc brakes.
  4.  
  5. Start the race squarely into the hub and carefully seat the race using an appropriate tool.
  6.  

Check the bearings for cracks or pitting. Check the races for scoring or pitting. If it is necessary to replace either the outer or inner bearing, it will be necessary to replace the bearing as an assembly (bearing, inner and outer race).

To install:

  1. Use a high temperature front wheel bearing grease to repack the inner and outer bearings before installation. Apply grease to the inside of the hub assembly before installing the inner bearing.
  2.  

Do not mix different kinds of greases, as mixing may change the grease properties and result in poor performance.

  1. Apply a thin film of grease to the spindle at the inner and outer bearing seat, shoulder, and seal seat.
  2.  
  3. Put a small quantity of grease inboard of each bearing race in the hub.
  4.  
  5. Fill the bearing cone and roller assemblies 100;pc full of grease. It is extremely important to work the grease thoroughly into the bearings between the rollers, cone and the cage.
  6.  
  7. Place the inner bearing cone and roller assembly into the hub. Then, using your finger, put an additional quantity of grease outboard of the bearing.
  8.  
  9. Install a new grease seal using a flat plate until the seal is flush with the hub. Lubricate the seal lip with a thin layer of grease.
  10.  
  11. Carefully install the hub and rotor assembly.
  12.  
  13. Place the outer bearing cone and roller assembly in the outer bearing race. Install the washer and nut. Draw up the spindle nut. Do not overtighten.
  14.  
  15. Torque the spindle nut to 12 ft. lbs. (15 Nm), while turning the rotor assembly forward by hand to fully seat the bearings.
  16.  
  17. Back off the nut to the just-loose position. Tighten the spindle nut by hand, then loosen until either hole in the spindle lines up with a slot in the nut (Not more than 1 / 2 flat). Install a new cotter pin and bend the ends of the cotter pin against the nut. Cut off any extra length to ensure that the ends will not interfere with the dust cap. Install the dust cap using a rubber hammer.
  18.  
  19. Install the brake caliper then install the wheel and tire. Torque the lug nuts to 100 ft. lbs. (136 Nm).
  20.  
  21. Lower the vehicle to the floor. Pump the brake pedal before moving the vehicle to check brake operation and to fill the calipers with fluid.
  22.  

1988 Models

The 1988 models are equipped with sealed hub and bearing assemblies. Refer to the Sealed Wheel Bearing Diagnosis Chart in .


CAUTION
Some brake pads 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. Raise the vehicle and support with jackstands.
  2.  
  3. Remove the wheel and tire assembly.
  4.  
  5. Remove the brake caliper and support with a wire to the surrounding body.
  6.  
  7. Remove the rotor assembly.
  8.  
  9. Remove the three hub and bearing assembly-to-steering knuckle attaching bolts.
  10.  
  11. Press out the old bearing using an arbor press and press in new bearings.
  12.  

To install:

  1. Place the hub and bearing assembly on the spindle. Install the hub and bearing assembly-to-steering knuckle attaching bolts and torque to 220 ft. lbs. (260 Nm). Install the brake caliper and torque the mounting Torx® bolts to 74 ft. lbs. (100 Nm). Install the wheel and tire assembly and torque the lug nuts to 100 ft. lbs. (136 Nm). Lower the vehicle and pump the brake pedal a few times before moving the vehicle.
  2.  

ROTOR INSPECTION



Thickness Variation Check

The thickness variation can be checked by measuring the thickness of the rotor at four or more points. All of the measurements must be made at the same distance from the edge of the rotor. A rotor the varies by more than 0.0005 (0.013mm) can cause a pulsation in the brake pedal. If these measurement are excessive, the rotor should be refinished or replaced.

Lateral Run-out Check
  1. Remove the caliper and hang from the body with a piece of wire. Install two inverted lug nuts to retain the rotor.
  2.  
  3. Install a dial indicator to the steering knuckle so that the indicator button contacts the rotor about 1 inch from the rotor edge.
  4.  
  5. Zero the dial indicator.
  6.  
  7. Move the rotor one complete revolution and observe the total indicated run-out.
  8.  
  9. If the rotor run-out exceeds 0.0015 in. (0.040mm) have the rotor refinished or replaced.
  10.  

Refinishing Brake Rotors

All brake rotors have a minimum thickness dimension cast onto them. Do not use a brake rotor that will not meet minimum thickness specifications in the Brake Specifications chart at the end of this section.

Accurate control of rotor tolerances is necessary for proper brake performance and safety. Machining of the rotor should be done by a qualified machine shop with the proper machining equipment.

The optimum speed for refinishing the rotor surface is a spindle speed of 200 rpm. Crossfeed for rough cutting should range from 0.010-0.006 in. (0.254-0.152mm) per revolution. The finish cuts should be made at crossfeeds no greater than 0.002 in. (0.051mm) per revolution.

 
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