When I drive over a crack in the road at low speed 5-10 mph, I hear a clinking noise from the rear of my car. After closer examination it is the caliper jiggling just a hair back & forth. The car drives great and the brakes exhibit no problems. Should it float on the rotor in such a manner?
The car is a 1991 300D.

CJ, how did you make the diagnosis with the car standing still ? There is a small amount of play between the pads and the caliper rails. There is usually an insert between the pads and caliper pistons that keeps things quiet. If your pads are rattling, then the inserts are missing or you have a set of pads that are a shade too small. Are you sure it's not something else...like a CV joint going bad, or a suspension part tha's loose or damaged. Keep looking, but first check for those inserts between the pads and caliper pistons.. BTW, the caliper itself should not be loose.

I had a mechanic tell me once that they sometimes have to use a center punch and a hammer to put a couple of dimples on the edges of the pads where they meet the caliper to prevent noise, as the pads are a little too small.

Hmmm...I'm not buying that the caliper's making noise. I'd guess that your parking brake is adjusted too loosely, and that's what is knocking around back there. Had this happen on my 500E. Adjusted the P brake; noise gone!

Good luck!

Parking brake adjusted, noise good...now I sleep well at night!

Hehe. See? Nearly 1,000 posts...it was only a matter of time before I solved something!