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    1986 Cadillac Eldorado 4.1L TBI 8cyl

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    GM Full-Size Trucks 1980-1987 Repair Guide

    Front Hub


    Locking front hubs are standard equipment on all 4-wheel drive models. The purpose of locking hubs is to reduce friction and wear by disengaging the front axle shaft, differential, and driveline from the front wheels when 4-wheel drive is not being used.

    The engagement and disengagement of the hubs is a manual operation which must be performed to each hub assembly. Unlocking should only take place when the transfer case lever is in the two wheel drive position. The hubs should be placed in the full Lock or full Free position or damage will result.

    Do not use 4-wheel drive unless the hubs are in the Lock position. Locking hubs should be run in the Lock position for at least 10 miles each month to assure proper differential lubrication.


    See Figures 1, 2 and 3

    Click image to see an enlarged view

    Fig. Fig. 1: Cutaway view of four wheel drive steering knuckle

    Click image to see an enlarged view

    Fig. Fig. 2: Exploded view of manual locking hubs

    Click image to see an enlarged view

    Fig. Fig. 3: Exploded view of automatic free wheeling hubs

    Including Wheel Bearings

    See Figure 4

    Click image to see an enlarged view

    Fig. Fig. 4: Removing the spindle

    This procedure requires snapring pliers and a special hub nut wrench. It is not very easy without them.

    1. Raise and support the front end on jackstands.
    3. Remove the wheels.
    5. Lock the hubs. Remove the outer retaining plate Allen head bolts and take off the plate, O-ring, and knob. Take out the large snapring inside the hub and remove the outer clutch retaining ring and actuating cam body. This is a lot easier with snapring pliers. Relieve pressure on the axle shaft snapring and remove it. Take out the axle shaft sleeve and clutch ring assembly and the inner clutch ring and bushing assembly. Remove the spring and retainer plate.
    7. Remove the wheel bearing outer lock nut, lock ring, and wheel bearing inner adjusting nut. A special wrench is required.
    9. Remove the brake disc assembly and outer wheel bearing. Remove the spring retainer plate if you don't have locking hubs. See Brakes for details on brake drum or disc and caliper removal.
    11. Remove the oil seal and inner bearing cone from the hub using a brass drift and hammer. Discard the oil seal. Use the drift to remove the inner and outer bearing cups.
    13. Check the condition of the spindle bearing. If you have drum brakes, remove the grease retainer, gasket, and backing plate after removing the bolts. Unbolt the spindle and tap it with a soft hammer to break it loose. Remove the spindle and check the condition of the thrust washer, replacing it if worn. Now you can remove the oil seal and spindle roller bearing.

    The spindle bearings must be greased each time the wheel bearings are serviced.

    1. Clean all parts in solvent, dry, and check for wear or damage.
    3. Pack both wheel bearings (and the spindle bearing) using wheel bearing grease. Place a healthy glob of grease in the palm of one hand and force the edge of the bearing into it so that grease fills the bearing. Do this until the whole bearing is packed. Grease packing tools are available to make this job easier.
    5. To reassemble the spindle: drive the repacked bearing into the spindle and fill the seal end of the spindle with grease. Install the grease seal onto the slinger with the lip toward the spindle. It would be best to replace the axle shaft slinger when the spindle seal is replaced. See Axle Shaft Removal and Overhaul for details. On 1980-82 models, the chamfered side of the thrust washer should be toward the slinger. Replace the spindle and torque the nuts to 33 ft. lbs. (45 Nm) on 1980 models and 65 ft. lbs. (88 Nm) on 1981-87 models.


    1. To reassemble the wheel bearings: drive the outer bearing cup into the hub, replace the inner bearing cup, and insert the repacked bearing.
    3. Install the disc or drum and outer wheel bearing to the spindle.
    5. Adjust the bearings by rotating the hub and tightening the inner adjusting nut to 50 ft. lbs., then loosening it and retightening to 35 ft. lbs. Next, back the nut off 3 /8 turn or less. Turn the nut to the nearest hole in the lockwasher. Install the outer locknut and torque to a minimum of 80 ft. lbs. (108 Nm) on 1980 models, 160-205 ft. lbs. (216-277 Nm) on 1981 and later 1 /2 and 3 /4 ton models, and 65 ft. lbs. (88 Nm) on 1 ton vehicles. There should be 0.001-0.010 in. bearing end-play. This can be measured with a dial indicator.
    7. Replace the brake components.
    9. Lubricate the locking hub components with high temperature grease. Lubrication must be applied to prevent component failure. For 1 /2 ton 1980-82 and 1980-84 3 /4 and 1 ton models, install the spring retainer plate with the flange side facing the bearing over the spindle nuts and seat it against the bearing outer cup. Install the pressure spring with the large end against the spring retaining plate. The spring is an interference fit; when seated, its end extends past the spindle nuts by approximately 7 /8&inch;. Place the inner clutch ring and bushing assembly into the axle shaft sleeve and clutch ring assembly and install that as an assembly onto the axle shaft. Press in on this assembly and install the axle shaft ring.

    You can install a7/ 16 in. bolt in the axle shaft end and pull outward on it to aid in seating the snapring.

    1. Install the actuating cam body in the cams facing outward, the outer clutch retaining ring, and the internal snapring. Install a new O-ring on the retaining plate, and then install the actuating knob in the Lock position. Install the retaining plate. The grooves in the knob must fit into the actuator cam body. Install the seals and six cover bolts and torque them to 30 ft. lbs. Turn the knob to the Free position and check for proper operation.

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