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My 2011 Audi A4 has been sitting for about 2 months in a garage. Today I drove it and as I went faster than 15 MPH I noticed a bad grinding noise and vibrations; even when I'm not braking. If I move the wheel in any direction except almost completely straight, the grinding / vibrations get worse. Braking actually helps with the vibrations and noise. Note that my ability to brake isn't affected, I can still brake with the same force I'm used to. I turned around and examined my rotors: enter image description here I'm no brake expert but these look bad. This one in particular is the worst, the others aren't as bad. I've read online that sometimes this rusting will come off after braking a bit due to the pads rubbing it off.

First, could these issues be caused by a rotor in this condition? If so, is this something I should wait out for this to happen, or should I stop driving / get these replaced?

Edit:

I took the car out today and here are 2 videos which show the issue:

  1. Car at idle - No issues, car sounds perfect - https://www.youtube.com/watch?v=k2cFREtBqQ4&feature=youtu.be
  2. Driving - The sounds are kind of obvious, but it's more like a constant "woob woob woob" or "reeb reeb reeb" noise - https://www.youtube.com/watch?v=4RrrQc46f9A&feature=youtu.be (Skip to around 4:10 for a better view of my steering wheel and speedometer)

Sorry for the bad video and it being upside down at times, I was trying to concentrate on driving and give details, so I wasn't paying attention to my camera orientation.

These don't sound exactly like the sounds, but you get the idea. Watching these again and listening to it a little distorted, it almost sounds like a bearing issue; it seems similar to like when your fan's bearing is starting to go and it makes like a humming noise.

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    Generally rotor surface rust comes off after only three or four braking stops. – zipzit Jul 14 '17 at 7:35
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I don't think its disk corrosion causing the noise as that should wear off after a couple of miles driving/braking. If I'm hearing it correctly though it sounds like a wheel bearing type noise as its speeding up with road speed. If however its making this noise when you rev the engine when stationary, my initial thought would be water pump bearings as its a sort of whine too.

  • Yes, it definitely varies with speed. It also does not happen if I'm stationary in neutral and rev, it's only when the wheels are actually spinning. I'm going to jack up the car and see if there's any play in the wheels to verify. – William Jul 17 '17 at 14:48
  • The wheel bearing ended up being the issue. I took it to the dealership and they replaced the front left wheel bearing and the noises went away. – William Aug 23 '17 at 12:52
  • Happy to hear you got it sorted 👍 – Orb Aug 23 '17 at 12:55
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Yeah, the rotors could be the noise. You can drive it and see if it gets better since your braking is normal. You could clean both the rotors and brake pads with some fine sandpaper. Or replace the brake pads and replace/machine the rotors.(If drilled rotors can be machined)

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The picture you posted does not match your symptoms. The rotor you show is in pretty good condition, but you have only shown us one surface. Frequently the interior surfaces delaminate, and for some reason more so on VAG cars. So you have to stick your camera under the car and get some more pictures.

If I were to service these rotors, I would start by merely knocking off the rust ridges at the edge of the pads. A screwdriver, cold chisel or even grinder can help you do that.

You could have bearing problems or something else, but my guess is that your rotors have some rust. If it can be knocked off, they will work fine and be quiet. If they are delaminating, on some other surface, then you will have to replace the rotors and pads.

Go for knocking off the ridge area, and checking for delamination first.

As long as you have reasonable braking ability a little running of these brakes is not likely to harm anything, and could even resolve your noise, although I encourage removal of the rust ridge anyway.

  • Once it stops raining this week (because that's not going to help the rust at all...) I'm planning on sanding things down a bit and taking it back out and recording the sounds and editing my post. I watched a few videos of the sound of what a bad wheel bearing sounds like and it could be similar, but I'll have a better frame of reference when I take it out again. – William Jul 12 '17 at 23:57
  • I would not sand the braking surfaces...they look OK in this picture. And you can turn the rotor and listen to where the sound is. Have you taken the car out for a little run doing some moderate braking? You can do that during the rain, as long as your brakes are functional. – mongo Jul 13 '17 at 4:38
  • Videos added to the original post, if those help your answer at all. – William Jul 14 '17 at 0:15
  • Listened twice, and I really can't sort the noise out well, as for example there is no spatial (directional) content. I would use them a bit, and when you take the wheels off, knock off any scale at the outer and inner portions of the disc. Also make certain that your dust shield isn't hitting the rotor. From the audio it mostly just sounds noisy, not anything specific for me. Then again I was never a sonar operator on a sub. – mongo Jul 14 '17 at 2:41

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