I have this strange knocking noise in the rear of my car everytime I hit a hard bump. I recently installed springs in the rear. I have checked all three bolts on the both lcas, and have checked the wheel lug nuts. I have also checked the two bolts on the top. Everything is tightly secured. I don't belive they are bottoming out because the drop was only about an inch. (there are H&R sport springs for a dc put on a ek hatch, so the drop is rather minimal, especially in the rear since ek hatch weighs so much less) What could it be? Someone suggested that it is the springs coming loss from the top mounts and slapping them hard again when it lands? Any ideas?

 

bump

 

Maybe the top of your passenger side lower control arm could be hitting your exhaust tubing?