GM Buick/Oldsmobile/Pontiac/Full-Size 1975-1990 Repair Guide

Axle Shaft, Bearing and Seal

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Two types of axles are used on these models, the C-lock and the non C-lock type. Axle shafts in the C-lock type are retained by C-shaped locks, which fit grooves at the inner end of the shaft. Axle shafts in the non C-lock type are retained by the brake backing plate, which is bolted to the axle housing. Bearings in the C-lock type axle consist of an outer race, bearing rollers, and a roller cage retained by snaprings. The non C-lock type axle uses a unit roller bearing (inner race, rollers, and outer race), which is pressed onto the shaft up to a shoulder. When servicing C-lock or non C-lock type axles, it is imperative to determine the axle type before attempting any service. Before attempting any service to the drive axle or axle shafts, remove the axle carrier cover and visually determine if the axle shafts are retained by C-shaped locks at the inner end, or by the brake backing plate at the outer end.

REMOVAL & INSTALLATION



See Figures 1, 2, 3, 4 and 5


CAUTION
Since the brake shoes will be exposed as you perform this procedure, note that brake shoes 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! If you have to clean in the area of the brake shoes, use a commercially available brake cleaning fluid to remove any brake dust first.

Non C-Lock Type

Design allows for maximum axle shaft endplay of 0.022 in. (0.558mm), which can be measured with a dial indicator. If endplay is found to be excessive, the bearing should be replaced. Shimming the bearing is not recommended as this ignores endplay of the bearing itself and could result in improper seating of the bearing.

  1. Remove the wheel, tire and brake drum.
  2.  
  3. Remove the nuts holding the retainer plate to the backing plate. Disconnect the brake line.
  4.  
  5. Remove the retainer and install nuts, finger tight, to prevent the brake backing plate from being dislodged.
  6.  
  7. Pull out the axle shaft and bearing assembly, using a slide hammer.
  8.  
  9. Using a chisel, nick the bearing retainer in three or four places. The retainer does not have to be cut, merely collapsed sufficiently, to allow the bearing retainer to be slid from the shaft.
  10.  
  11. Press off the bearing and install the new one by pressing it into position.
  12.  
  13. Press on the new retainer.
  14.  

Do not attempt to press the bearing and the retainer on at the same time.

  1. Assemble the shaft and bearing in the housing being sure that the bearing is seated properly in the housing.
  2.  
  3. Install the retainer, drum, wheel and tire. Bleed the brakes.
  4.  



Click image to see an enlarged view

Fig. Fig. 1: Axleshaft, wheel bearing and seal

C-Lock Type

If the axle shafts are retained by C-shaped locks, proceed as follows:

  1. Raise the vehicle, support with jackstands and remove the wheels.
  2.  
  3. Remove the differential cover. Then, remove the differential pinion shaft lock-screw and the differential pinion shaft.
  4.  
  5. Push the flanged end of the axle shaft toward the center of the vehicle and remove the C-lock from the end of the shaft.
  6.  
  7. Remove the axle shaft from the housing, being careful not to damage the oil seal.
  8.  
  9. Remove the oil seal by inserting the button end of the axle shaft behind the steel case of the oil seal. Pry the seal loose from the bore.
  10.  
  11. Seat the legs of the bearing puller behind the bearing. Seat a washer against the bearing and hold it in place with a nut. Use a slide hammer to pull the bearing.
  12.  
  13. Pack the cavity between the seal lips with wheel bearing lubricant and lubricate a new wheel bearing with same.
  14.  
  15. Use a suitable driver and install the bearing until it bottoms against the tube. Install the oil seal.
  16.  
  17. Slide the axle shaft into place. Be sure that the splines on the shaft do not damage the oil seal. Make sure that the splines engage the differential side gear.
  18.  
  19. Install the axle shaft C-lock on the inner end of the axle shaft and push the shaft outward so that the C-lock seats in the differential side gear counterbore.
  20.  
  21. Position the differential pinion shaft through the case and pinions, aligning the hole in the case with the hole for the lockscrew.
  22.  
  23. Use a new gasket and install the carrier cover. Be sure that the gasket surfaces are clean before installing the gasket and cover. Torque the cover bolts to 22 ft. lbs. (30 Nm).
  24.  
  25. Fill the axle with lubricant to the bottom of the filler hole.
  26.  

Special limit slip differential fluid is needed to properly lubricate the limit slip carrier clutches or cones. Standard fluid may cause damage to the rear axle assembly.

  1. Install the brake drum and wheels and lower the vehicle. Check for leaks and road test the vehicle.
  2.  



Click image to see an enlarged view

Fig. Fig. 2: Removing the axle shaft



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Fig. Fig. 3: Removing the axle bearing



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Fig. Fig. 4: Installing the axle bearing



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Fig. Fig. 5: Installing the axle seal

 
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