Only the front wheel bearings require periodic maintenance. A premium high melting point grease meeting GM specification 6031-M must be used. Long fiber type greases must not be used. This service is recommended at the intervals in the Maintenance Intervals Chart or whenever the van has been driven in water up to the hubs.
Before handling the bearings, there are a few things that you should remember to do and not to do.Remember to do the following:
Do not do the following:
REMOVAL, PACKING & INSTALLATION
Sodium based grease is not compatible with lithium based grease. Read the package labels and be careful not to mix the two types. If there is any doubt as to the type of grease used, completely clean the old grease from the bearing and hub before replacing.2-Wheel Drive Models
See Figures 1 through 14
- Raise and support the front end on jackstands.
- Remove the wheel.
- Dismount the caliper and wire it out of the way.
- Pry out the grease cap, remove the cotter pin, spindle nut and washer, then remove the hub. Do not drop the wheel bearings.
- Remove the outer roller bearing assembly from the hub. The inner bearing assembly will remain in the hub and may be removed after prying out the inner seal. Discard the seal.
- Clean all parts in a non-flammable solvent and let them air dry. Never spin dry a bearing with compressed air! Check for excessive wear and damage.
- Using a hammer and drift, remove the bearing races from the hub. They are driven out from the inside. When installing new races, make sure that they are not cocked and that they are fully seated against the hub shoulder.
- Pack both wheel bearings using high melting point wheel bearing grease for disc brakes. Ordinary grease will melt and ooze out, ruining the pads. Bearings should be packed using a cone-type wheel bearing greaser tool. If one is not available, they may be packed by hand.
- Place a healthy glob of grease in the palm of one hand and force the edge of the bearing into it so that the grease fills the bearing. Do this until the whole bearing is packed.
- Place the inner bearing in the hub and install a new inner seal, making sure that the seal flange faces the bearing race.
- Carefully install the wheel hub over the spindle.
- Using your hands, firmly press the outer bearing into the hub. Install the spindle washer and nut.
- Spin the wheel hub by hand and tighten the nut until it is just snug; 12 ft. lbs. (16 Nm).
- Back off the nut until it is loose, then finger-tighten it. Loosen the nut until either hole in the spindle lines up with a slot in the nut and insert a new cotter pin.
- There should be 0.001-0.005 in. (0.025-0.127mm) end-play on 1987-90 models. On 1991-97 models, end-play should be 0.005-0.008 in. This can be measured with a dial indicator, if you wish.
- Replace the dust cap, wheel and tire.