00 N20Bird

Hello,

I recently installed UMI 2-point subframe connectors, UMI adjustable panhard rod, and UMI tubular lower control arms. After I put the control arms on, and before the PHR, I noticed a tiny bit of sound coming from the rear of the car when I was driving. Nothing bad really. After I put the PHR on, the sound got worse. It could be related, but I doubt it - I'd attribute it to just the time factor, since the LCA's were on about 2 weeks before the PHR.

The sound seems to be coming from the driver's side rear of the car, and only happens when the car is moving. If I accelerate normally, then let off the gas, I will hear this repeated "thumping" noise from the rear of the car. The faster I'm going, the more it makes this noise. I've looked under, tightened everything I could, and done some trial and error, but haven't been able to fix it.

If I have the car off, and put the e-brake down and push it, I will hear a simliar squeaking sound coming from the rear of the car. I try to pull on all the suspension pieces and all of them seem to be tight as possible and have no movement in them.

The bushings for all of these pieces are only greased on the outside part, the part that has contact with the body. I do not have a grease gun so I did not put grease into the zerk fittings. Could this be what is causing this noise? It is getting very noisy and I can hear it over my exhaust most of the time. It just sounds like something constantly tapping at the rear of the car, and although it does not sound bad, or hinder the performance of the car at all(it's actually definitely quicker with these new suspension pieces, my friend who previously was dead even with me, I now pull a car on), I would like to get rid of it.

Any ideas?

Cal

iTrader: (1)

It's because your LCA bolts are not tight enough. You have to torque them pretty good to get the sides of the bracket to pinch the sleaves so they don't bang. I suggest you look up the torque spec and use a torque wrench. Same thing happened to me a long time ago.

UMI Performance

iTrader: (77)

Yes exactly, the rear mount of the SFC sandwiches the front mount of the lower control arm. When you tighten the bolts down the SFC mount isn't letting enough force to be placed on the control arm to make it tight enough. The factory torque setting is 72 ft. lbs. although we have found torquing them up to 90 ft. lbs. to take care of the clunk, try this and I assure the sound will be gone. If you have any more questions please ask.

Thank you,
Ryan

jimmyblue

iTrader: (11)

I believe the same holds true for the Panhard mounts,
when I (over)greased my adjustable it spread the tabs
and things got real clunky out back until I put some
thick fender washers on (to make the wimpy sheet
metal go flat) and dogged the mount nut/bolt down
tight.

radz282003

iTrader: (1)

If the LCAs are adjustable, check the jambnuts. I have had these loosen on me, a couple times, and it sounds similar to what it seems you are hearing.

00 N20Bird

Re-tightened and greased everything, and it still made the noises.

Took it to my mechanic and he said it's the rear diff...time to start saving for a 12-bolt

Z28Streetwimp

iTrader: (3)

The poyeurethane bushings will transmit more noise into the body of the car, so any noise from the rear end will become more noticeable. If the noise is from the rear end, you might try changing the differential fluid. I would recommend Red Line or Lucas synthetic 90W140, and add some GM limited slip additive. Even though Lucas and Red Line both contain limited slip additive, it's not enough and the posi will still make noise. Anyway, this may not fix your problem, but it can't hurt and it's cheap.... Good luck.