My automatic A4 has 65,000 miles and to my knowledge the brakes are still factory and have not been replaced. The car drives and sounds fine except for when I hit exactly 30 mph! It kind of builds up around 25 mph and then fades out at 35 mph. The best way I can describe the noise is groaning, humming, borderline grinding sound without the feeling that anything is actually catching (to my knowledge). My first reaction was that it was a front rotor, but it makes the noise when I am accelerating and naturally slowing down (without the brake). If any of you guys have any experience with this and or think of anything it could be please let me know. The car only has the 8 yr motor warranty left, so if it is a belt or rotor issue then I am on my own. Just trying to come up with something before I head to Mr. mechanic.
Thanks guys

 

What year is it? Could be caliper pistons are suck somwhere and causing your pads to rub your discs. I thought a read somwhere that as the pad wears down the car will adjust the pad closer to the disc as to keep the same amount of break pedal travel.

 

The car is a 2004

 

sounds like wheel bearing

 

Yeah.. unlikely that there is anything wrong with the calipers. But hey, you're driving an Audi!

 

my guess is cat converter. when its goes out, the parts can burn up then rattle around inside. at just the right amount of torque you can hear it loud. if you can get under it, give all the cats a knock with your fist to see if you can hear the noise. this happened to me, and it was loudest when it decellerated because of the back pressure. also, check for codes

 

But he was saying that the sound is there when slowing down and not applying the brake. Which means the engine would be reving down.

 

umm.. exactly as i said. when the engine is reving down there is most back pressure and that can make all the parts inside the cat rattle louder if one of the cats is indeed blown.

 

Drive at 25-35 mph where you hear the sound, slightly turn the steering wheel. If the sound gets softer when you turn the wheel toward the sound, and louder when you turn the steering away, it is most likely the wheel bearing.

 

ui had this issue but mine wasnt till i hit highway speed, like 65+ it deff could be bearing they are cheap off ECS tuning