follow-up to X3 squeak

[dak]

The dealership keeps telling me that the high-pitched squeak is being caused by rust build-up on the rotors from being exposed to outdoor moisture (rain, humidity, etc.) It builds up on rotors and the pads and causes this. They are telling me it burns off with driving and using brakes. Sound right to anyone?

[Kevlar]

Rust on the rotors is normal with humidity/rain etc... but the squeak you are talking about, can you ellaborate on that some?

[dak]

It is consistent with the rotation of the back right tire, and it sounds like a high-pitched squeak. There does appear to be more rust on the rotor than the others. It does it under 25mph while accelerating, driving, or breaking but not in reverse. Let me know if you need any more info...thanks for the response.

[Kevlar]

It may be an overly tight emergency brake (just first thought off the top of my head).

Does it do it all the time or only in the morning when the car has not been driven for a while?

[Goon]

Is it always there or does it disappear after a while?