Author Topic: How To Repack Your 4WD Front Wheel Bearings  (Read 6376 times)

Offline Dr_Snooz

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How To Repack Your 4WD Front Wheel Bearings
« on: August 21, 2015, 12:19:37 AM »
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.



Yeah.

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.

Gulp.

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.
« Last Edit: August 22, 2015, 11:06:21 PM by Dr_Snooz »
1986 GMC C-2500 Crew Cab, 7.4L, TH400 -- RIP Chester

1989 Chevy Suburban V-2500, 5.7L, TH400

1990 Chevy C-3500 Ext. Cab, 7.4L, 3L80

Offline Irish_Alley

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Re: How To Repack Your 4WD Front Wheel Bearings
« Reply #1 on: August 21, 2015, 12:45:45 AM »
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
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Offline enaberif

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Re: How To Repack Your 4WD Front Wheel Bearings
« Reply #2 on: August 21, 2015, 08:40:47 AM »
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 (http://toolmonger.com/wp-content/uploads/2008/02/Bearing%20Packer%20Composite.jpg) and this makes sure the bearing is properly packed otherwise you could can premature wear on your bearings.

Offline Irish_Alley

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Re: How To Repack Your 4WD Front Wheel Bearings
« Reply #3 on: August 21, 2015, 12:18:05 PM »
also edit the post so you have a list of the tools you had to use in the second paragraph
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Offline pholliday1

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Re: How To Repack Your 4WD Front Wheel Bearings
« Reply #4 on: August 21, 2015, 03:06:43 PM »
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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Offline Irish_Alley

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Re: How To Repack Your 4WD Front Wheel Bearings
« Reply #5 on: August 21, 2015, 05:12:01 PM »
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 !!
now wheres the fun in that
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When you have eliminated the impossible, whatever remains, however improbable, must be the truth ~Sherlock Holmes

Offline roundhouse

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Re: How To Repack Your 4WD Front Wheel Bearings
« Reply #6 on: August 22, 2015, 07:16:17 PM »
And if you have one of those vacuum packer things in your kitchen
You can put the bearing and grease in the vacuum bag like your food....

Just don't let the wife catch ya


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Offline Irish_Alley

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Re: How To Repack Your 4WD Front Wheel Bearings
« Reply #7 on: August 22, 2015, 08:16:19 PM »
i know someone just did a post on how to repack the bearings but i cant find it. does anyone know where it at?
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Offline pholliday1

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Re: How To Repack Your 4WD Front Wheel Bearings
« Reply #8 on: August 23, 2015, 05:26:33 PM »
I'm going with the vacuum packer idea!!!
VETERAN AND LIFETIME NRA MEMBER. WHAT DO YOU STAND FOR?
1991 V3500 CREWCAB SRW 454TBI GMC
1991 v3500 crewcab SRW 454tbi 480le 6" lift
1990 V3500 crewcab Dana 60 FF 14b 5:38 ratio 40 inch 11" lift
1989 v3500 crewcab 454TBI 5" lift

Offline Dr_Snooz

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Re: How To Repack Your 4WD Front Wheel Bearings
« Reply #9 on: August 24, 2015, 09:34:27 PM »
Has anyone ever had a bearing failure from insufficient packing? I'm relatively new to GM, but I've changed numerous wheel bearings on the Hondas I've owned, both sealed cartridge and conical. I've only ever done the smear and turn method on conical bearings and have never had a failure. I do pull the bearing to make sure the grease did actually penetrate the retainer, of course. The sealed cartridge units come pre-greased and they are far from packed. In fact, I'd call it more of a light coating than anything.

Just wondering.
1986 GMC C-2500 Crew Cab, 7.4L, TH400 -- RIP Chester

1989 Chevy Suburban V-2500, 5.7L, TH400

1990 Chevy C-3500 Ext. Cab, 7.4L, 3L80

Offline roundhouse

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Re: How To Repack Your 4WD Front Wheel Bearings
« Reply #10 on: August 24, 2015, 10:04:10 PM »
I've never had it happen to anything I was maintaining

But I've bought a few trucks with a spun bearing that damaged the spindle and hub/rotor

One truck we bought had gotten so hot that it melted the plastic knob on the lockout


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Offline Greybeard

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Re: How To Repack Your 4WD Front Wheel Bearings
« Reply #11 on: September 03, 2015, 11:59:22 AM »
I've never had a front bearing fail but I always pack them via the glob of grease in the palm after cleaning them spotless with brake cleaner. I did have the rear bearings fail on a 14bFF because I was interrupted by a severe thunderstorm while doing a brake job once and when I got back to it I forgot I had torqued the retaining nut but never loosened it up (young and dumb so I never double checked), it cut and melted the rear spindle in half and the wheel came out going around a corner near my house. A quick jaunt to the salvage yard where I picked up another out of a van (van axles are wider by a few inches I believe), only that one turned out to have a Gov-lock in it and it still worked.
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Offline Don5

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Re: How To Repack Your 4WD Front Wheel Bearings
« Reply #12 on: September 03, 2015, 01:09:36 PM »
I always put a glob of grease on the heel of my hand right below my thumb and push the bearing down into it. When you pack a bearing correctly you will have very little grease left on your hand. This was taught to me back in the day long before vacuum sealers and fancy grease packers. It worked back then and it still works today. The cost to my wallet has been zero. If you learn to do this correctly, you will always do it like this. Old school. Hey those guys must have known something huh? 
It's been a LONG time since I have been called a newbie. Just sayin....

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Offline Greybeard

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Re: How To Repack Your 4WD Front Wheel Bearings
« Reply #13 on: September 03, 2015, 08:46:06 PM »
I always put a glob of grease on the heel of my hand right below my thumb and push the bearing down into it. When you pack a bearing correctly you will have very little grease left on your hand. This was taught to me back in the day long before vacuum sealers and fancy grease packers. It worked back then and it still works today. The cost to my wallet has been zero. If you learn to do this correctly, you will always do it like this. Old school. Hey those guys must have known something huh?

Woo Hoo!  8) The finer points of grease packing. One thing is technique, put the grease in through the end of the bearing and push it out the cage not the other way around. That way the edge of the bearing scrapes all the grease off the palm. And for those inexperienced in cleaning bearings, never use gasoline or diesel fuel to fine clean a bearing, they can be used to get the heavy gunk off but always use something that does not leave a residue for the final cleaning (brake cleaner or similar) and never spin a clean dry bearing, especially with compressed air. Any residue keeps the grease from bonding with the steel and forming a barrier. It's anal I know, but in forty years of doing this, never had a bearing fail from improper packing. I learned from the old pros. Some things just cannot be improved. Of course, we all know California finds fault in everything, and as such everything in their eyes causes cancer; so if you believe that nonsense, pack them so you don't get your hands dirty. But remember not to breath while doing so because grease fumes probably cause cancer too (at least from their point of view).   ;)
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