New Rear wheel bearings too tight?

[boatbuilder]

I was attempting to fit new rear wheel bearings this evening and I now have a problem. First thing to say is the surfaces on the bearing carriers were spotlessly clean and smooth without even a scratch or a speck of dirt.

I was able to tap in the inner ones myself at home using the old bearings ok but the outer bearings were very tight. I measured them before fitting and they were about 0.5mm bigger diameter than the hole (and that was after they had been in the freezer all night)

So off I went to my local tractor garage who pressed them in carefully with a 46mm socket - I watched him do it and he did it very carefully and they went in really easily on the press. Problem came when trying to pop the inner cage in place - it was very tight and had to be lightly tapped in with a hammer. Then when in place, it wouldn't turn easily - after a bit of wrestling to get it to turn, it turns roughly and it feels like its going over little regular bumps all the way round.

Not sure what to do now - both bearings are doing the same thing ...
Bearings were bought off German ebay - brand is ATEC 10660886

[lloydy]

Might just be that they are a cheap brand? FAG and FEBI are normally the ones to go for.

[silverbullet]

How did you measure this 0.5mm difference?
I would expect bearing outer races to be dead size.

If the bearing was that tight and now its "lumpy" then the bearing may have been faulty (oversize) and stretched the bearing housing.

[silverbullet]

Having said that, "pressed in with a socket" has got alarm bells ringing. You should always fit a bearing with a machined mandrel, a socket is only forged to shape.
The bearing could also be c0cked in the housing.
I bought an ATEC front wheel bearing kit for the syncro from ATP.
The fit was good and the only tightness is the drag from the new seals.

[boatbuilder]

I measured the diameter with calipers before I fitted the bearings - didn't write the sizes down but remember thinking hmm its about half a mm too big. Makes sense I suppose that if it was too big it would have had to be crushed a bit to get it to fit, resulting in the tightness and maybe the inside of the cage buckled a bit - will examine it when I take it out...
I used a new 46mm socket if that counts! Looked pretty flat to be honest...
There was no writing on the actual bearing, just on the cardboard box - just cheap rubbish I reckon - 21.96 pounds for an entire back end bearing kit - should have known better I suppose.

Have just ordered FAG ones from Brickwerks...

[silverbullet]

0.5mm isn't a bit, it's a lot!

[Paul Weeding]

0.5mm isn't a bit, it's a lot!

Especially when it's a diameter..

Really should only be a few thou bigger for a interference fit!!

[boatbuilder]

Hope it hasn't damaged the bearing carrier - FAG bearings now on order from Brickwerks...
I have a new set of ATEC tapered bearings for the front as well so hopefully there won't be any problems with them...

[croc]

Really should only be a few thou bigger for a interference fit!!

Absolutely

[boatbuilder]

Well I got the fag bearings today and the other supplier of the atec cheap ones sent me another one of theirs. No difference in diameter that I can tell. Outer casing seems to be made slightly differently. The atec ones have 15 rollers and the fag ones have 16. And maybe there could be a difference in the quality of the metal but you can't tell by looking at it.

[boatbuilder]

The new bearings fitted perfectly... no messing about, they went in without a press, just a hammer and flat bar to get it started, then a 46mm socket.
They are the exact same brand as the originals. Only stamp missing is the vw logo!