wheel bearing question

When driving and gaining speed hear a repetitive hum, which gets faster with speed. When turning left the hum is much more audible. Think it is wheel bearing, but can't say which wheel it is coming from. Any thoughts?

Thank you folks, bimmerfest is the best

Definitely sounds like a failed wheel bearing. If it gets louder when you turn left, the failed bearing is probably on the right hand side of the car, since you load up the right side of the car when turning left. As far as front or rear goes, you'll have to use your best judgement to figure that out. Usually isn't too hard to figure out, though.

Might be able to tell by spinning the wheel or hub by hand. Or you could use a deflector gauge to judge if it isn't riding straight.

Thank you gentlemen, I believe it is the rear right bearing...another question -

I just fixed my shocks on the rear passenger side. Since I had to put in new bumpstops, I had to loosen the center nut on the shock (sachs), had to go to a local shop who did it with an impact gun. Problem is now that I have the shock installed, I can't tighten it enough without the damned shaft spinning as I tighten with a wrench. There is a nice gap between the mount and the nut. Is it OK to drive around like that - I took it for a small spin and heard some knocking from that area every time I went over a bump. Does this mean that the nut needs tightening. And if so, how do I tighten the sucker?

Absolutely do NOT drive the car with the nut like that. With a gap like you are describing, the shock piston is essentially acting like a big slide hammer, and will rip out your shock tower very quickly.

Uh oh, thanks, I wonder if I can take it to the local repair guy without it ripping the tower. Btw, so how do I tighten that center nut? I assume I'll have to take the shock off again to tighten it? I was under the assumption that tightening would be a lot easier than loosening - thought that the shaft wouldn't move once the other end was hooked up to the trailing arm. No such luck - sucker moves like his life depended on it.

Btw, does anyone know the torque specs for that nut on the center of the rear shock. also what is the torque spec for the shock nut on the trailing arm? And the wheel lug nuts? I am thinking of buying an electric impact gun that will work from the car's charging port. Thnks.

it will spin freely till the cows come home.....look at the top of the shaft from inside the car...it probably has a shape to it...some shocks have a notch that a 6-10mm open end will fit on so you can hold it still while tightening the nut...that nut, by the way, may be of a type that is designed not to spin back out so it will be harder to tighten than the average nut....(be sure its not cross threaded, though...it should spin on fairly easily, then get tighter..even though there is plenty of thread left to go before you start compressing the rubber bushing). The advantage of an impact gun for this, is that it will tighten the nut in bursts...not allowing the shaft to spin very much if at all when given short bursts of the gun until the bushing just starts to bulge.....you want to compress it, but not too much...

JP

Hmm, that impact gun will sure make it a lot easier to remove the wheels, and bottom shock nut too. I also found this...don't know how it would work in the cramped space of the trunk though. I think I will have to remove the shock, tighten that center nut, and then re-install (argh!).

http://blog.bavauto.com/12134/bmw-an...ct-gun-how-to/