I had the same annoying problem with my rear disks recently. It sounded as if my car was going to fall apart going over little bumps.
Upon further investigation of the noise, I noticed that it was not the calipers (since they where fairly new) that where the problem, but the pads. The metal part of the brake pads seemed to have worn down at the area where they contact the backing plate to lock them into place. So to fix them I simply welded and finished off some extra material to the pads to make up for the difference. They don't even make as much as a squeak now. I would defiantly look into fixing or replacing the pads before spending money on new calipers.
Hope this helps
Troy
Upon further investigation of the noise, I noticed that it was not the calipers (since they where fairly new) that where the problem, but the pads. The metal part of the brake pads seemed to have worn down at the area where they contact the backing plate to lock them into place. So to fix them I simply welded and finished off some extra material to the pads to make up for the difference. They don't even make as much as a squeak now. I would defiantly look into fixing or replacing the pads before spending money on new calipers.
Hope this helps
Troy