blau928

Hi All,

Merry Xmas..!

I'm in the middle of repacing my rear wheel bearings and axle halfshafts, and had a few questions...

1. Does the race on the wheel hub get reused with the new bearing, or do you have to take off the old race and press on the new one..?

(Hub side only, as the hub carrier seems fine to press in the new bearing. I reused the old race with hub, and there is play in the hub after assembley, and full seating of the bearing in the hub carrier, so I am bewildered unless I am missing something, as I think there should be no play on yhe hub..!)

2. How did you take the old race off if you did..? (Mine seems like it's going to need a plasma cutter to melt it off.. Gonna try a MAP torch, but who knows..)

3. I have 2 sets of part numbers for rear wheel bearings for a 928, anyone know the difference

a. 999 053 055 02

b. 999 053 050 00

Part number a. is the new bearing I got from Int'l... Is the other is the old style...?


Thanks for the help..

James Bailey

Alway use the complete new bearing and most find that they MUST remove the wheel upright and press out the race and also press in the new. I have done it on the car using a large slide hammer to bang out the bearing and some threaded rod to pull in the new bearing far enough to get the stub axle in place to finish seating the bearing.

Jerry Feather

You must remove the half of the race(s) that stays on the hub when you press the hub out of the carrier. You do it by obtaining a two-bolt clamping devise that has semicircular knife edge surfaces on the inner edges and beefy bodies where the large bolts go through. You clamp this devise onto the hub just below the bearing race and then put the whole thing in your hydraulic press and push the hub out of the race. If you can't do it yourself take it to a machine shop and have them do it. I have heard that removing one of these bearings, no matter the condition, destroys the bearing simply because of this situation where one of the two inner races stays with the hub. That is probably why yours is loose when you reused the inner race.

Or, bring it over here and I'll help you with it.

What puzzles me is how did you you reuse the inner race on the hub without removing one from the bearing? I hope you didn't destroy the new bearing.

Jerry Feather, FBA Certified
S4's (6)
KGJT

blau928

hi Jerry,

Thanks for the tip.. I removed the new race that goes on the hub, and used the old one.. The bearing is fine.. I was thinking the old race needed to come out, but it seemed fine..

I'll take the hubs to a machine shop tomorrow and have the races removed...

Thanks much...!!

PS... Where are you located..? Just curious..

blau928

Hi Jim,

Thanks...! I have a hydraulic press, and am able to press in/out the bearings etc from the hub carrier.. Besides, I figured hammering = shock, and could upset the bearing clearance etc..

I was having issues with the race that is frozen on the wheel hub.. I'll take it to a machine shop tomorrow..

ROG100

Richard,
Both part numbers are the same part.
Latest part number is 999 053 055 02 the other is the old number.
Roger

Steen Jensen

blau928

When installing the new bearing I did the following...

1. Put hub carrier in oven at 250 degrees.

2. Buy 5 bucks worth of dry ice and cover the new bearing with it and cold soak for a couple of hours.

3. Drop bearing into hub carrier. No pressing required...no fuss , no mess...no chance of damaging new bearing.

Worked like a charm for me on both sides.

atb

Heating the carrier makes a huge difference. 250 degrees was what I used as well. I tried if first without and the race was not going to budge.(This assumes a destroyed bearing with just the race left). The factory type tool that allows you to pull the bearings while in the car keeps seems designed to keep them intact. The NorCal 928 guys have one that they rent out. Dr. Bob is the tool steward.

Jerry Feather

Hi Richard:

I am in Grand Junction, Colorado. That's western CO almost to Utah, on I70.

If you have your own Hydraulic press all you need is the tool I described. It is called a "Bearing Seperator." Harbour Freight has it for $19.99, which is the large size. I think that is where I got mine, although I think I have a couple. Their part number is 3979-1CWH, although the last four parts of the number may vary with the catalog. They probably have it is their store nearest you; and that will probably be about what the machine shop might charge for one of yours.

You will also need some kind of blocking to hold the seperator on in your press while you push the hub out.

I had a rear bearing failure in my first S4 which I discovered was caused by a loose axle nut. The nut was only just beyond finger tight and had no torque when I removed it. Being loose it had allowed the bearing to move slightly on the hub and the outer race literally ate the hub down by about a 32nd of an inch. I had to get another hub.

I kind of did what you did. I decided that the old bearing was probably ok since it looked ok so I put it back in on the new hub I bought. After it was all bolted up it had some play in it, so I did it all over and put the new bearing in. I think I also put a new one in the other side even though it was probably ok.

In the course of this project I also found that there was nothing left of my parking brake on the left side. It gave me a chance to rebuild that also.

When I was in the Air Force I learned that about 50% of all maintenance is caused by maintenance. I have found that to be true with all the 928's I have bought. Therefore, be sure to put all the required torque on you axle nuts when you are done.

Jerry Feather, FBA Certified
S4's (6)
KGJT

WallyP

I am bewildered - did the new bearing unit come apart? That seems odd...

James Bailey

The inner race is split in the middle and easily comes apart the bearing is a dual angular contact bearing with the crush set by how those halves fit together. That is why you can have that 250 lbs or so of torque on the axle nut without crushing the ball bearings ,they never feel it !

BC

Truer words are rarely spoken.

dr bob

FWIW, since I don't have a press: I used a MAPP gas torch to heat the race that was still on the hub. Do it quickly so you don't pass much heat to the hub itself, and the ring will expand off the hub. With the hub clamped in the benchtop vise, a few taps with a sacrificial chisel and the 16oz machinist's hammer popped the old one right off.

We have a Sir Tools B-90 wheel bearing tool in the SoCal tool collection. It includes enough pieces to remove and replace the rear wheel bearings without removing the uprights. Rob Edwards has it right now, and is trying the method in the instructions that doesn't require taking the parking brake shoes off. Using the B-90 tool, the rear bearings can be changed in less than 2 hours per side including moderate cleaning. Your alignment isn't disturbed at all, another plus. Fee for local use is nominal; I don't expect to ever recover the cost from others, but can safely say that doing my own car paid for the tool, balanced against the cost of having it done by our local 928-capable mechanic. ($400 for both sides plus bearings, but including alignment.) Rob has done both of his now, and the tool was loaned to the NorCal group for a clinic that Bill Ball hosted. Glad it's getting used!

blau928

Hi All,

Well, went to my dad's shop, turned out that he had all the bearing separators etc.. Got the old one off, turns out the new Japanese made OE PORSCHE bearings have a slightly different race than the German made (***) bearings.. Anyway, with hydrauic press and chem lube, no issues.. Slid out like a greased potato in tube of butter.

However, I damaged the bearing seal on one of the new bearings while taking it in and out after finding play in the hub, so I need another one... Monday... Anyhoody, one hub completely done, and the other needs the bearing I will order tomorrow.. Axles replaced, and ready to be torqued to spec.

The correctly assembled unit now has zero play.. The old hub was bad, as the shaft was worn from the old bearing gong bad, and that was the source of the play in the hub. I had ordered a hub from Int'l, and ended up using that as it was good..

Now the bumper cover is off, and the car is in 1 million pieces...... I have all that other stuff to attend to, like brakes, AWIC plumbing, pumps, radiator, oil coolers, and all that stuff on my really long list..

I think I'll also need to get a set of fendes from Louie...... Why did I have to get those huge rims and tires.....????? Hmmmmmm....

Thanks again guys

Jerry Feather

Hi Richard:

I'm posting here merely to move this thread up where it will be handy for Rob with his problem now.

Jerry Feather