rear shock rattle--87 528e

I replaced my rear shocks on my '87 528e about 6 mo's ago. Since then I have been getting a rattle or knocking sound whenever I go over a bump especially at low speeds. Since then I have had the shocks off several times, replaced the rubber gaskets and the upper mount bearings(that's where the sound seems to be coming from) to no avail. It almost sounds like there is a loose bolt or bolts but I assure you they are tight. Anyone out there had this problem and knows how to fix it? The car runs great, is restored and has 218k on it. Thanks

Have you checked what you got in your trunk?