Wheel Bearings

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Project Box
Part Number(s): 1163300051A Front - 1233500068 Rear
Part Cost: $40
Best Place to buy: Standard places
Cost to Have it done in a shop: $
Difficulty Level: 8
How long it may take: 2+ hours
Frequency: 80,000 miles?
Tools needed:
Special tools needed:

They say if your wheel bearings go out, you need to get the replaced ASAP. Mine didn't go out, but I was troubleshooting some mysterious noises that turned out to be upper controller arm bushings

Take off your front wheel and jack up your car.

You need to pop off the wheel bearing cap. A nice 2X4 and crowbar will do this without destroying your cap.

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Ah, the chewy goodness inside.

Another Angle, this is important! See how, and what angle that thing ?????????????? is on.It will need to go back on the same way.

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Now you can get a XX hex and unscrew that thing. Count how many rotations you unscrew that thing.

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Then just repack the new ones, reassemble, and enjoy.

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The rear ones are easier than the front ones, or so I'm told. But I don't think I did them. So submit it, if you do it. Grab your camera too.

WARNING: the following was put here from "Repacking Bearings - http://www.diymbrepair.com/Maintenance/Bearing/ Backup Copy of Wheel Bearings 1" and "300Dman" says this guy "sucks" and one shouldn't follow it. He is unable to correct it or write a better one.

REAR WHEEL BEARINGS The Haynes MB manual does not include this.

I would say they are significantly more difficult than the fronts.

1- prop car up with jack stands or equivalent at jack points with rear wheels dangling

2- remove wheels and brake caliper, hanging the caliper aside on coat hanger wire dangling so there is no tension on the brake hose. Remone the brake disk. Remone the central bolt which keeps CV axles engaged in the wheel hub. Remove parking brake gizmos.

3- use brass drift punch and hammer to drive axle as far as possible out of rear wheel flange ... it will telescope almost enough... don't keep hitting it after it stops moving freely .... mine wouldn't telescope far enough to just drop out of the hub.

4- lying under the very securely supported vehicle flex the outboard CV joint to its extreme .. it will almost be enough to shorten and release from the axle/flange .... rotate the flange and flexed outboard axle a bit back and forth... it will barely be able to clear and disengage from the hub. Using wire prop it up and forward out of the way.

5- using the mandatory pin wrench socket ( +/- $60) on a minimum half inch drive ratchet or breaker bar stabilize the large inboard nut on the wheel hub. The breaker bar will lie nice and stable right on the top of the trailing arm on the left side. On the outboard side of the hub use two lug nuts (or any M12/1.5 bolt) the type used on allow wheels or longer. Perch a large lever bar engaged across two lug bolts to rotate the hub and loosen the nut .... you will need to jump on the end of the lever. I weigh 230 to 240 lbs and I had to vigorously bounce on the end of an 18" bar. Thats about right .. they want something like 340 ft lbs of torque on that nut.

6- use a slide hammer to pull the hub out of the housing. Do not succumb to the temptation to drive it out from the inboard side with a punch, unless you do so in the following way: put the nut back on far enough so it is flush or a little above the hub then place a socket of suitable size in contact with the nut only and drive the hub out. It is important not to hit the hub with the hammer, only the socket which is in contact with the nut. I made the mistake of hitting the hub and was lucky to have a friend with a machine shop who used a lathe to trim damaged threads off it at the inboard threads. Those hubs are expensive. Paper towels are handy to manage the great gobs of grease. Get a shop with an appropriate press to remove that outer bearing race and press the new one on. My bearing froze solid ( in the exact moment I rolled into my garage to within 1 foot of the usual position I park in, it seized in that moment) and the hub had to be replaced. About $350 from online suppliers ... I paid $15 at one of those pull it your self wrecking yards. There are zillions of W123s.

7- Remove grease seals, the inboard drives out easily from the outside with a long punch or screwdriver ... the outboard was a bit stubborn. The bearing races mounted in the housing are driven out with a brass or bronze drift trimmed with a file so it has a nice crisp square presenting edge. Drive the inner one toward the midline of the vehicle from the outside and vise versa. Work in a circular pattern with hammer blows just strong enough that you feel a little movement with each blow. Carefully drive the new races in, all the way home. Get them started with gentle hammer taps until they will just stay in place without holding them and they are nice and square... then, using the old ones held against the edge of the new ones ..... tap the old ones with hammer blows just strong enough to give a little movement with each blow until all the way home. That will be obvious by sound and feel. Later when you torque that nut back down you may feel a little mushy spot just before it bears down seriously ... that would be the bearing races scootching that last fraction of a millimeter. That 340 ft/lbs of torque "pre-loads" this system and keeps things true while under working stresses of vehicle weight and operation.

8- clean everything very carefully ... grease liberally... put it back together the way it came apart. A) both inboard and outboard outer bearing races, lots of grease, outboard grease seal, inboard inner bearing race, spacer, inboard grase seal, inboard grease seal mating ring and lastly nut plus 340 ft/lbs torque.

I apparently was not as thorough as I should have been. Within a few months I began to hear a whaa whaa whaa sound at my left rear (that's the one that self destructed) and I had to do it over. When I took the bearing out the second time, up really close inspection showed the new bearing surfaces looked a little like the surface of the moon. Apparently one metallic fragment in the grease can fracture the new bearing surface and multiply into many fragments in a cascading patten of eventual quick destruction.

Also the one that failed initially ( at 27 years of age ...) apparently did so because the outboard seal had worn a deep groove in the steel surface it mates with on the hub ... did not do its job of excluding dirt .... the bearing was destroyed. Make sure the hub has a smooth surface where the seal meets it. Replace it if it doesn't. Make sure it has lubrication but not too much because grease outside the seal will end up on the parking brake friction surfaces by centrifugal force.

Repacking Bearings - http://www.diymbrepair.com/Maintenance/Bearing/ Backup Copy of Wheel Bearings 1