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How To Repack Your 4WD Front Wheel Bearings

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This is on my '89 Suburban, 10-bolt corporate axle with the 8.5" ring gear. This is my first 4WD, so it was all completely new to me. I set out on Monday with one mission: repack my front bearings. I set out again on Tuesday and again on Wednesday. I finally accomplished it today, Thursday. Because of errors in the manual, obscure special tools and lots of blank stares at the parts store, it took a lot longer than I anticipated. Hopefully this helps someone else.

Special stuff you'll need:
- 4-pin 4WD locknut socket (see below for pics and details)
- Torx drivers
- Snap ring pliers that push outward
- 3/8" hex key
- Dental pick kit
- Seal remover, a couple slotted screwdrivers and big crowbar or something to remove the old wheel seals
- Torque wrench capable of reaching 160 ft-lbs
- A flashlight is helpful
- Beyond this, you're going to need a basic tool kit including a ratchet, needle nosed pliers, Phillips screwdriver and so forth.

Unthread the 6 Torx bolts holding the hub locking mechanism, then remove the mechanism. There is no need to remove the Phillips screw holding the dial.

NB: the locking mechanism is a one-piece cartridge assembly. If yours springs apart into its component pieces like mine did, you need to fix that. I was able to thread mine back together using the opposite side as a reference.

Remove the small retaining screw and pull the inner gear.

Note that the gear is installed with the flush face facing outward. The inner gear teeth are recessed on the inside. Tried to get a pic, but it's blurry.

Remove the spring behind the gear.

Remember that you should have removed the caliper first, then remove it.

It is held on with 3/8" hex bolts.

Threaded from the inside.

The caliper rests nicely on the steering linkage.

You've noticed, no doubt, the deep grooves carved in this rotor and here's why.


The caliper guide bushings came out with the pins, so I need to replace those. They are held in with rubber orings that disappeared long ago. Too bad I'm poor, so these are going back in smeared with some RTV to provide cushion.

Aside from the deep grooves, the rotors are brand-new, full thickness. I'd hate to throw half the rotor away by trying to machine this out, so I'm going with the grooves. The pads will wear to them.

Remove the snap ring on the spindle.

Then go change your torn glove.

Remove the retaining ring from the inside of the hub. It's nearly impossible to see and harder to remove. You'll need some dental picks of various shapes.

Thread in a couple of your Torx bolts to help pull out the locking gear mechanism.

The adjuster locknut is next up and requires this special socket to remove.

The locknut is supposed to be torqued to 160 ft-lbs. Mine threaded off easily by hand.


Remove the locknut

Now pull the retaining plate. Note the holes and the inner tang at the 3 o'clock position in the photo below.

Thread out the adjuster nut. It uses the same socket as the locknut. The adjuster nut looks just like the locknut with one very critical difference. The adjuster nut has a pin. You can see it at roughly the 1 o'clock position in the photo below.

The adjuster nut puts the correct preload on the wheel bearing. The pin pokes through one of the holes in the retaining plate. The retaining plate tang keys into a slot on the spindle which prevents the adjuster nut from rotating. The lock nut holds them both together tightly.

Pull the rotor off carefully. It's heavy. The outboard bearing will fall out the front of the rotor. Catch it and set it aside. On the back side of the rotor is the bearing seal. Remove it.

Super icky old grease! Remove the inboard bearing.

Now is a good time to address any other suspension issues you have going on. Replace bad lug studs while you have the rotor off. Inspect your caliper for leakage. Lube the chassis. Inspect your brake hoses for cracking. Inspect your shocks for oil leakage. Check your suspension for failing ball joints, pitman arms, rubber bushings, etc.

Clean and inspect the bearings and races. You'll have to decide how clean you want the bearings before you re-grease them. If the grease is dry and crumbly, you probably want to remove every last trace of it with a parts brush and solvent. Of course, if the grease is that bad, the bearings probably are too. My bearings were in good shape and the grease was too, so I did a paper towel wipe and moved on.

There is a lot of differing opinion on the best way to repack bearings. You can buy special tools if you want. I just smear a big gob of grease across the rollers, stuff it back in the hub and give it a good turn.

I usually pack some additional grease around the bearings inside the hub, then re-assemble.

Now inspect your spindle. My spindle is rusty.

Obviously my seal failed, allowing water inside the hub. Closer inspection revealed some rusty dings on the sealing surface of the spindle. I used a flat file to knock them smooth, then greased it. Hopefully this will be enough.

According to the manual, the bearing is designed to "creep" around the spindle, so smear some additional grease on the spindle where the bearings will seat.

Install a new seal using your special tool. My special tool is a block of wood from the scrap pile. It doesn't really matter what you use as long as it lays flat across the entire face of the seal and can stand a few good whacks from your deadblow hammer.

If you are very careful removing the old seals, you may be able to reuse them, but the overwhelming likelihood is that you will deform and/or completely destroy them, so replace the seals with new.

Thread in the adjuster nut. This is the one with the pin on it. Install it so the pin is facing outward (toward you).

1. Torque the adjuster nut to 50 ft-lbs while rotating the rotor. This will seat the bearings.
2. Back off the adjuster nut until loose and torque again to 50 ft-lbs while rotating the rotor.
3. For manual locking hubs, back off the adjuster nut just until loose.

Install the retaining plate. MAKE VERY SURE that the pin on the adjuster nut seats in one of the holes on the retaining plate (it will take a flashlight, a needle-nosed pliers and a few tries) and that the tang on the retaining plate slides into the slot on the spindle. This will prevent the adjuster nut from backing off over time.

Install the locknut and torque to 160 ft-lbs.

Install remaining parts in reverse order.

Before installing the caliper, take a moment to wipe your greasy fingerprints off the rotor with some Acetone and a paper towel.

Torque the caliper guide pins to 35 ft-lbs.

If you need to verify the operation of the locking hubs, you can do so now. In the locked position, the U-joint in the axle should turn when you spin the rotor. In the free position, it will not.

Put the wheel back on and road test.

Be happy.

sticky. nice write up, i know we have one by beastie_3 but this one goes into a little more detail
You can find his Here if you need info on replacing the ball joints

Good write up but one piece of information is that what you did by packing the bearings doesn't actually pack the bearings. You need to do this one of two ways.

First way is put globs of grease in your hand and fill the bearing INSIDE until it comes out but this is super messy.

The better way is pick up a cheap bearing packer ( and this makes sure the bearing is properly packed otherwise you could can premature wear on your bearings.

also edit the post so you have a list of the tools you had to use in the second paragraph

Also just using a plastic quart zip lock bag with some grease in it and just knead/push the grease through the bearing and no mess !!


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