Note: this is for my 4th gen, didn't get any help on the lighter weight ls1 boards, so I decided to post here as well.

Ever since I had KBDD SFCs installed, one of my rear lower control arms rattles around and thunks on big bumps. First, I jacked up the car, tightened the bolt to 100 ft-lbs, still rattling. 140 ft-lbs, still rattling.

So, I tried tightening the bolts under load. I loosened both sides, then tightened them evenly. Still rattling, on the same side as before. I turned several more 1/4 turns on the "loose side", still rattles. Now, I'm stumped. The rattling side is tightened much more than the other side.

What could be the problem, could the bushing have been screwed up (by the welding heat) when the SFCs were put in? Could the SFCs be causing the bolt to not sit flush? Any ideas are appreciated.

Thanks, Dave '01 WS6, '91 GTA

 

Yes, it is likely that the bushings have slop from welding in the sfc without removing the trailing arms. If you've got to replace the bushings then you might as well spring for a set of adjustable trailing arms. Take more care when you or someone you know modifies your car. Getting in a hurry won't help. It just makes life miserable and then you don't ever want to do it again. There's nothing like the feeling of a job well done.