M3 Brakes

[convertibleguy]

I was noticed a slight vibration upon relatively heavy braking from high speed plus a low frequency rumble upon braking at most speeds so took the car in to have it checked.

I was surprised when the dealer changed the rotors, pads and sensors on both the fronts and backs; the car has around 31K miles on it. I did take it to the track for the first time about 3 weeks ago so that obviously put quite a bit of stress on the fronts. I guess that I'm not surprised that the fronts needed changing.

The question: I noticed that there is a different part number for the left front and right front rotor. I was wondering if anybody knew what the differences were between the rotors such that they need to be unique by side. The backs are common part numbers for both sides.

Glad it's under BMW service, my guess is that it's $1,100 for parts alone for this work at the dealer....

[Matthew C Smith]

I believe the fronts have directional venting on the inside of the rotor.

I'm surprised they covered the brakes. I figured those would be wear items...