I have a 1989 420 SEL great car,heard what sounded like a caliper bouncing in the left front ,removed calipers replaced all rotors and pads with factory new, it really needed them, now the noise is more frequent. When I apply the brakes ever so little and drive over rough road there is no longer any noise,remove foot from brake noise returns. This is driving me crazy,don't know what could be rattling. Any help would be very much appreciated.

Tim,
Have you checked you wheel bearings. If the noise goes away when you apply the brakes, it could be the bearings.
Bill Lewallen Lexington,Ky. Home of LexMark Printers.

Check the slides in the caplipers they may be loose or have some play in them enough to rattle. Especially if the rattle stops when a little pressure is applied to the brakes. If there is play, it will be apparent. Good luck and let us know what you find out.

klunking sound
 

The wheel bearing seem to be OK,I cleaned and repacked and inspected them replaced wheel grease seals, did not see any excess wear in the caliper slide aera, but will recheck same. Th anks for the tips, will let you all know what I find, a friend had mentioned maybe sway bar bushings? or lower shock mount? Thanks Tim

Tim: Make sure the noise is in the front. There are a few common thunks in the back, one being the hydraulic pressure reservoirs, which I've seen a number of posts about, and one fairly common (and expensive) problem is the bearing for the caliper mount on the rear, all 126's with self-levelling have these bearings. It will cause a complaint like this, thunking in the rear unless the brake is applied. Come to think of it, your car may also have a diagonal brace in the front that can thunk under these circumstances( only when brake not applied), if I were under you car I could point it out to you. If you look under the car, I am sure you will see this brace running at an angle to the lower arm, there is a rubber mount for it that wears out. Since your problem goes away with brake application, I don't think sway bar bushings would be the cause of your noise, brake application wouldn't affect it that much, if at all.....Gilly

Klunking sound
 

Pulled the left front wheel today,found that the brake pads were loose on the caliper pins, made a couple of adjustments and all is fine now. I really do thank all who responded to my request,

Thank you all for your help, Tim