RaulZ209

I lowered my car on skunk2 springs with stock struts. Everything was fine before. Now the rear right side makes a noise like of a "clunk" like if something moves. What could it be? I already took it apart and put it back together again but it still happens. It happens when i go over bumps. I tried jumping on it in my garage and everything but i cant get the noise by jumping on it only when going over bumps. What can it be?