A few months back I had my BMR boxed SFC's welded in. Ever since then, I've been getting this rattling noise coming from the rear driver's side.

The noise sorta sounds like a door that isn't completly closed.

Anyway, I've crawled under the car to take a look, and everything seems fine. At first I thought maybe the bolt that goes thru the lower control arm wasn't tightened enough. The BMR instructions recommended torquing them to 90ft/lb, but I couldn't get my torque wrench in there to tighten it, so just tightened it as much as I could by hand.

I checked the bushing, and it seems OK as well. Even when I rock my car back and forth by putting my foot on the driver's side kickplate, it'll make the same rattling sound.

But mostly I can hear it when I go over bumps or railroad tracks.

Hell, I even took it to the speed shop that installed my headers, and they can't find anything wrong either. All welds are good, the SFC's seem nice and tight.

Any suggestions? I'm stumped on this one...

 

You say it does it when you rock the car... get a buddy to get down there and listen for it while you rock it. I think it might be the shock or rear hitting something.

 

did you check the panhard rod? the sway bar bushings/links?

 

Problem solved...

Turns out the 3/4" nut on the bolt that holds the LCAs and the SFCs together was siezed up, and a little cross threaded. When you would try and tighten it, the entire bolt would spin around.

Tried loosening it, but same thing... bolt just turned. Ended up taking a cutting torch and melting the nut off... then buying a new bolt, but this time I used the factory locking style 3/4" nut... and torqued it down like a ****...

... and no more rattling! Not even over the worse potholes or railroad tracks!