Hey All, I am glad to be part of Audi Forums, unfortunitly I come to you with a problem with my much loved 2001 Audi A4. It has picked up a hum from the rear end. This hum disappears what I make a right hand turn. I have checked tire pressures and wheel bearings and was unable to pin point the problem. Has anyone else dealt with this problem before? The car has 182000 KM and I have used it to its full abilities before.

Any help would be appreciated. Thanks

 

It's most likely (about 99.999%) your right rear wheel bearing. By checking them I assume you mean shaking the wheel - they can be bad without being bad enough for the wheel to move. I'm also going to bet that, since it goes away in a right turn (when the right side suspension is unloaded), it either already or will soon get louder in left turns (when the right side suspension is loaded). And finally, these cars are known to eat bearings like popcorn. There's a chance you could have an issue with a tire, which you can check by swapping front to rear, but my money is on the bearing. The kit is under $60 shipped from www.germanautoparts.com for the bearing and end axle bolt. Make sure you get that bolt. The torque is insane and you wouldn't want to reuse the existing one if you can help it.

 

What you describe sounds exactly like the wheel bearing. You say you checked them? What method did you use? Sometimes you can lift the vehicle and detect play but not when the problem first appears.

 

I can testify to a wheel bearing that hums and does not physicaly show there is an issue - as in jacking it up and trying to twist the wheel to see play in it. My front hummed for about 6 months before it really started to sound nasty during turns. Don't put it off too long or you may be replacing a hub with that bearing like I might have to do.

 

Thanks guys, it does sound like a wheel bearing now. I was really hoping it wasn't in the rear diff. As soon as I get back from work i'll change both rear bearing. Any I should know before I take this on?

 

Just make sure you have a shop lined up that will press out/in the hub and bearing for you... I guess $40/side is the going rate. Unless you are lucky and know somebody with a hydraulic shop press. Don't attempt to use the hubshark, or any sort of handheld puller/press. It might be doable but will frustrate you to hell.