firebirdStud

I know at first thought this could be anything in the rear suspension. But, I have checked everything I can think of! Im at my wits end with this thing.

So, before I wreck something, I thought I would post here to try to get some insight.

Mods in the sig, its far from stock. I have checked all the bolts I can get a wrench on: lower control arms, upper and lower panhard bars, torque arm, driveshaft yoke, bottom shock mounts. I have played with the axles and they are still tight in there.

The only thing I can think of is the upper shock mounts? Do these ever go bad? Ive got 125xxx on the clock. I have had it on a lift alot, so the rear is suspended by the shocks.. could this have done something?

The clunking sounds like it is in the passenger rear area. I have checked the spare tire and jack, both are tight and dont move.

This happens at medium sized jars to the suspension.

Any clariffication needed just ask... but I am stumped here.

THANKS!!!
Cody

firebirdStud

or maybe polly bushings went bad? I have lakewook action traction bars, with the action deleted. I would guess maybe 35xxx miles on these babies?

RedHottG2

I had a clunking I couldn't get rid rid of but it it went away when I did my full UMI roto-joint suspension. I replaced one piece at a time pretty much and guess what ? When I replaced my factory LCA's it went away. That's right, turned out to be worn bushings in my stock 54K mile LCA's. Look closely at that. GL!

firebirdStud

How exactly can you tell if your polly bushings are now giving too much? I have those lakewood bars, with the action part deleted. So it is just like a conventional square tube control arm with yellow polly bushings in them. Please tell me how to check if they are shot.
Thanks!
Cody

bluz28

Check the exhaust hanger on the passenger side rear for play in the hanger bushing, this could cause the the over axle pipe to hit on the PHB support or the axle tube itself.

firebirdStud

I checked it out, and yup the pipe was hitting the frame by the spring. I gently persuaded it with a hammer and now it fits in there without hitting the upper panhard bar or the spring cup.

The damn clunking is still there!!! UGH it just wont go away!

firebirdStud

it almost sounds like something is loose, but I have been all around the suspension with nothing found. Since I cant see the tops of the rear shocks, is it common for the shocks to become loose where they bolt up top?

Injuneer

The shock upper shaft sticks through a hole on the chassis. There is a rubber bushing and a washer above the chassis sheet metal and below the chassis sheet metal. The top nut on the shaft compresses the bushings slightly when tightened to the correct torque. The bushings may have cracked. Since it takes about 15 minutes to pull a rear shock, its something you should check.

In a severe case, its possible the sheet metal could tear where the shaft goes through it. Not likely, but possible. Spohn, for example, supplies a reinforcing pad that he recommends to protect the sheet metal when installing coil-overs in the back. Again, its so easy to check, you should take the time.

It also possible the rear shocks are internally damaged after 15 years.

chevy_dude97

yeah I am pretty sure I know the sound, I havent figured mine out yet.
I only have 52K miles on my ride and it sounds pretty loud. Not trying to hijack just have same problem.

DAVE00

You guys ever figure this out? I have something very similar and I am going to check the rear shocks and upper isolators on the rear springs as well this weekend. Everything else in the suspension looks good.

chevy_dude97

I found out why mine was clunking, turned out the y pipe back had come loose, the whole exhaust was shifted rearward just slightly to allow the over axle loop to hit. I replaced the u clamp on the y after shifting the whole thing forward and bam sound gone.

edgarda2

i have the same problem on my car but mine does it when its really coldd

chevy_dude97

yeah when it was cold it would do it at first, then it just started doing it at certain rpms, check your exhaust connections. shake it and look at the connections to see if any are loosened

edgarda2

that's what i first checked but they're pretty good
it must be my shock or end links or something down thereee

chevy_dude97

did you check the bend in the exhaust? I noticed a little rust patch just above the rear end and it turned out to be where it was hitting because the loop was just so slightly back and allowed it to contact. You may also want to bang on your cats to see if there is anything loose inside, or check all the mounts underneath to include the trans, torque arm and sway bars for wear. Does it sound louder when you hit bumps?