brake rattle??
 

I don't know why I never asked about this before, I've had the problem for almost a year lol and first noticed on an ex-gf's E36 328is and then on my X5 after installing new brakes:

THEY RATTLE!! if you drive over bumps/lane markers you hear a very obvious rattling sound which goes away as soon as you start to apply brakes.

I've asked dealers about it and they say it's nothing important, just an imperfect brake fit ... not sure how that's not important lol but ok :)

any thoughts?!

I had a similar problem on my 330xi after installing a set of Hawk HPS pads. The pad length is 1-2 mm shorter than stock and the clip that goes inside the piston is fairly flimsy so the pad on the piston side kept bouncing up and down in the pad carrier. The outside pad is fine because the anti-rattle clip holds it tight.

The fix was to bend the piston clip so that it fit tighter inside the piston.

What pads do you have?

haha same pads :)

hmm...check the rotor assembly, if it is a two peace rotor, it usually comes with antivibration clamps, if so....they could be out of place and need to be replaced or put back into the shaft...gotta get it up on a lift and roll the wheel...listen for the rattling noise n locate it on a much complicated diagnosis.

There you go. My bet is that it's the same problem. It only gets worse as the bouncing up and down causes the clip to become even looser.

BMWs in general seem to be prone to "caliper click".