Hi I have just changed the rear wheel bearing in Situ, and what a wierd design the hub is?? Is everyone elses the same?? The bearing is pressed in from the outside up against a shoulder cast in the hub, and once in there is nothing to stop it coming back out, most bearings i have done before press in like this but have a circlip to phisically lock them into place, but on the hub there was no circlip groove or circlip-- Granted the bearing was hellishly tight to come out and as far as i can see the only method of holding is when you torque the bearings up the force compresses the bearing like 2 tapers being driven against each other to expand the outer shell into the hub locking it in, as the drive shaft will not take any axial load. So In theory it might be possible to jar the back bearing hard enough by dough nutting and clipping something hard wnough to push the wheel out of the hub, then the only thing stopping it coming all the way out is the brake disk?? Here is a rough sketch of what it looks like:
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Everything should be made as simple as possible, but not simpler.--:Albert Einstein -
that is not strange.it look like this in all audi 80/90/s2/vw modells in front end and for thoose carswho have quatro....in audi 100/200 they have the circlips in the outher part of hubs -
To me it is another example of poor engineering on behalf of Audi, same as the crank shaft pulley bolt which has the job of transmitting the torque of the engine to the cylinder head, instead of the crank pulley having a taper fit on the crank or a Carbon steel key fit onto the shaft the bolt does all the work, i know it works well but it leaves little margin for error if things are not perfect then it will not work. For safety sake the bearing should have a circlip just as a back up if nothing else. Oh well, been out for a drive today and all seems well, need to give it a good run and take some temperature readings to make sure all is well. The old bearing was shot, the grease ran out and stank to high hell-it had lost all its constituency and was black, burnt and poured out like very old engine oil. My whine has gone and all seems well.Everything should be made as simple as possible, but not simpler.--:Albert EinsteinComment
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Originally posted by Graham
Agreed Graham.......same on my car and I didnt think it was a very clever design
Just done my front too...funny you should mention temperature readings.......
The monkey who pressed my front bearing in managed to pop the inner protective dust shield off it while pressing it into the car.....Thought it may be ok as it was still on the bearing just not properly seated.......
NOPE
10 degrees higher temps than all the other wheels....so Im going to take it off again and am buying my own 25tonne press to redo it again (not paying another monkey)....A royal PITA though....Comment
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an other thing,the grease in the org bearing are some ****,so i use to open the dustrings(use a knife)carefuly,and fill the bearings with the MOBIL xhp222 grease in,and set in the dustrings back,the grease are BLUE coluored. its the grease they use on heavy loaded lorrys.its the BEST grease to use in the most places.in the outer joint and so on.Comment
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yeah but doesn't the hub bolt hold it all together?just done mine(took it off though)had to tie some string to the abs cable so i could pull it back through.Originally posted by GrahamComment
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Originally posted by philS2
Yeah.....the hub bolt is torqued to 200 NM + 90 degrees
and though the hub is a press fit to teh bearing...it passes though that and the bearing andf bolts into the CV joint ....meaning that provided it doesnt come loose then the bearing should be forced against its seat by the hub,......and the hub by the hub bolt!!!!!
Still agree with graham that a circlip would be a safe addition though?!Comment
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The bolt has no holding effect on the bearing, it only compresses the bearing, the CV Joints on the drive shaft are free to move axially to a certain degree and the amount of play is more than enough to spell disaster, if the bearing did move the bolt will just pull the drive shaft into the hub causing it to probably destroy both the hub and driveshaft. I Left my hub attached by the strut and tie rod, only disconnected the bottom ball joint to give me clearance to swing the drive shaft out of the way, i noted how seized in and how destroyable the ABS sensor was--thats the last thing i need to buy another sensor. Luckily all is well.Originally posted by philS2Everything should be made as simple as possible, but not simpler.--:Albert EinsteinComment
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Dont forget the new grease inside will be alot stiffer and the bearing will run at slightly higher temps till it breaks down slightly. The bearing is a pretty tough design and when torqued will be pulled into the correct position.Originally posted by s2dudeAgreed Graham.......same on my car and I didnt think it was a very clever design
Just done my front too...funny you should mention temperature readings.......
The monkey who pressed my front bearing in managed to pop the inner protective dust shield off it while pressing it into the car.....Thought it may be ok as it was still on the bearing just not properly seated.......
NOPE
10 degrees higher temps than all the other wheels....so Im going to take it off again and am buying my own 25tonne press to redo it again (not paying another monkey)....A royal PITA though....
10 degrees isnt alot, if it was 60 degrees then there would be something wrong, take the car for a short blast to the illegal speed zone and take readings after a high speed run, if a massive difference is apparent then something is possibly wrong as you say 
Everything should be made as simple as possible, but not simpler.--:Albert EinsteinComment
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