I just got some B&G coilovers installed in my car. I'm getting a wicked rattle from the back when I go over bumps, cracks and potholes. I put the car up on some jack stands and checked every nut and bolt I can think of, and they're all tight. It's not the endlinks, control arm, sway bar, brake caliper, etc (all the usual culprits of a rattle). I shook the suspension around and couldn't replicate the noise. I'm lost. Anyone know what it might be?

[EDIT] I also used the jack to put a compression load on each side of the car under the lower arm and checked the opposite side to make sure there are no clearance or rubbing issues. The noise is most prolific from the rear passenger side, but the rear drivers side also makes the same rattle.

I'm taking the car to the Nurburgring tomorrow and I really want to get this figured out before I make the problem worse.

Thanks!

 

I hear a lot about the top nut on B&G's being hard to tighten down, and that you should use an impact wrench (which I don't have). So, today after work I'll be giving that a try.