I have had a noise for a couple of weeks on my S - it is my 3rd car so I do not drive it much. I finally took the time to find it and found that the inner brake pad on the LF wheel is loose and rattles about causing the noise I am getting. All brakes and pads are OEM except for the rotors.

Anyone run across this - it appears all the pads have a certain amount of looseness how they fit.

 

Chances are you have a missing spring retainer clip. These clips prevent the pad from rattling around. Did someone replace or remove your pads sometime in the past? If not, the only other possibility is that one of these spring clips broke or is bent. If you remove the pad, you can check them out.