CamaroTom

I have a 1995 Z28. The car is stock except for an SLP Level 1 suspension (Eibach springs, Bilstein shocks, 1LE sway bars, rear control arms and panhard bar) and 17 x 9 ZR1 wheels with BFGoodrich g-Force T/A KD tires. The car has 17,000 miles on it. The suspension was installed three years ago and the car has only been driven about 900 miles in that time.

When I cruise down the street on smooth pavement everything is fine. But when the road surface gets a little choppy or I cross some railroad tracks, I hear an annoying rattling from the rear suspension. I take it very easy over tracks since the car sits so low, and I try to drive on the smoothest roads possible. I've checked the tightness of the rear control arms and panhard bar and they're torqued to factory specs. The springs appear to be installed correctly, as do the shocks. The parts were installed on a lift where the car's weight was supported by the wheels. I've went as far as to grab each part and see if they had any play in them and they don't budge. Other than the noise, nothing appears to be wrong. The car handles and drives great, but the rattling drive me nuts. What is wrong and how do I fix it?

Side note: On the bottom of the rear springs, which way should the cut end of the coils point?

Like My Taillights?

My LCA bushings squeek going over big bumps. Is it a squeek or a rattle? Could it be your exhaust system rattling? Just a few things to check, good luck.--Rob

CamaroTom

It's definitely a rattle. I never thought of the exhaust making noise, since it's the only stock part still on there and I don't remember it rattling before the SLP parts went on. What could the exhaust be rattling against?

Black6spdZ

check your rear brake pads, mine does the same thing and if i put my foot on the brake it goes away.

OBE1 95Z28

Bottom of my springs point to the sides, not the front/back. Is your exhaust touching anywhere on bumps?

CamaroTom

Nope. Everything seems to be in order. The cut ends of the coils on my car both point forward.

Camaro37

Maybe check the torque arm bolts, mine rattled extremely bad when those bolts were loose.

GRANDEJIM

I have a 2002 with the same problem. The dealer is trying to tell me that it is just the 1LE suspension....but I'm not buying that. It sounds like, but is not a tailpipe, and your right on smooth streets it's fine but a brick or bad asphalt street and it just rattles.

Ideas would be appreciated as the dealer is stumped and the warranty is running out fast. Do others of you with the 1LE suspension have the same problem?

Thanks

Deenasty

mine does the same thing, and it drives me nuts!

TobyZ28

I had a rattle/clunky sound from the rear of my before but It was actually not from the suspension... It was from my rear trunk. I have a Vert so my trunk is probably a bit different, but something to check for anyhow.

stock98z

Had a bad rattle/chirping noise in the rear of my car once. Turned out to be the spare tire tools/jack. Stuffed a rag between the metal parts and fixed the problem. Just a thought (although if you've narrowed the problem down to the suspension, not a very good one).

gavster1

Dont know if this too late for you, but check the 2 retaining clips that hold the park brake shoe to the backing plate. When I was chasing rattles in the rear of my 99 Z28, I found that the clip on one side was unclipped, and the one on the other side was clipped but very loose.
I removed each clip, and held it in the vise and used a small hammer to re-tension the clip before re-installing. This seems to have cured a lot of rattling from the rear-end.

(Prior to this I also had both rear wheel bearings replaced and am using Mobil 80-140 Synthetic oil and GM additive.)

The reply to my mail message to Torsen (diff manufacturer) said that "the helical gears in the Torsen diff centre will make a rattling noise when the diff is not under load, typically when coasting at around 20Mph".
That's why I am using 80-140 diff oil.
Only other action I am now doing is to put some extra sound deadening into the rear of the car to reduce the Torsen rattle.

Good Luck,
Gavster1.

zkmfdmz

you guys mentioned everything except the panhard bar

i did a full rear end swap and got that same noise, like a bunch of loose cardboard boxes in the rear under choppy bumps right?


check the bolts and nuts on your rear panhard bar, mine was loose and when i tightened it the noise went away