Originally Posted by mswaz

I was at the dealer today getting the ARS module replaced on my M and asked the shop foreman about the squeak while braking in reverse. He stated it was the cosmoline(sp?) they put on the rotors for shipping. He said it will wear off eventually or I could do some hard stops in reverse to burn it off sooner. Size of the rotors and hard pads make it more prevalent on the M's.

Not sure if this reason holds water but I guess makes some sense...

Thoughts?