I have a 2012 M37x with 60k miles. It has developed a noise when I apply the brakes. The noise comes and goes, but it is there most times I brake. I hear the noise as I am slowing down, getting nearly stopped. It is not the normal sort of grinding noise or rotating noise that one would associate with a brake. It is a noise that sounds like a horn blowing, but quite faint. Think of the sound of a French horn or a stadium horn, blowing a single tone, sort of a faint groaning. It seems like something that would be associated with an air leak or a vacuum leak.

Has anybody had such a noise who could help me with a diagnosis?

If you brake much harder or feathered, light braking can get the car to NOT make the noise? I have found rear brakes can make odd noises since they generally do not apply as hard as the fronts.

Let me try this out and see what happens. Thanks.

Debonair wrote:If you brake much harder or feathered, light braking can get the car to NOT make the noise? I have found rear brakes can make odd noises since they generally do not apply as hard as the fronts.

I had this same problem, when the idiots I brought the car from put on the wrong brakes. Every-time I tapped the brakes, car made a horrible sound like aloud rubbing noise( that was very annoying) took it back to them and they replaced the rear brakes for free. might want to check ur rear brakes like Debonair said.