80 Series Rear Suspension

[BLC]

Hi Guys,

I've had a strange knock in the back of my 1992 80 series GXL for a few months now and heaps of time spend gazing underneath the car, I still dont seem to be able to figure it out.

The noise sounds like a metal to metal clunk, and only happens over short sharp bumps ( i.e. speed bumps) It doesn't seem to happen when i drove over ultra slow, but if i drive over at walking pace, as the rear of the car starts to comes down it clunks....

It has a 3 Inch spring lift installed a year or so ago, when on a hoist at full drop, the springs are slightly loose but prolly only move up and down 5mm
( I dont think that going over a speed bump at a relatively slow speed would shoot the rear of my car to maximum drop? or am i completely wrong)

The upper and lower control arm bushes seem to be fine, and the sock bolts are tight, as well as that little plate that the shocks bolt into. The only thing i can see or feel that is loose, is the D bushes on the swaybar ( the swar bar has extended links to the chassis.

The swaybar appears to be sliding side to side through the D bushes by about and inch or so each way

So my questions are:

How tight are the D bushes supposed to hold the swaybar in?

Does anyone have anymore ideas as to what this could be?

Thanks in advance

Nik

[Dane]

How did you check your control arm bushes? You should use a decent lever bar and if they move they are probably no good. Hard to tell by just looking at them.

Sometimes coils will move as they compress and make a clunking sound which is hard to diagnose while the vehicle is stationary.

My money is on the control arm bushes.

[rezpkt]

Hi Nik

Loose baffles in sub tank perhaps? give the fuel tanks a good kick.

Place your hand on upper and lower control arm bushes and get someone to rock your car backwards and forwards in gear, you will be able to feel movement in bushes this way.
Might pay to remove and check panhard rod bushes too, they usually go first.

Remove sway bars and throw in bin

Good luck.

[BEAR 80]

I had a similar issue, turned out to be the rubber over lay to the top of the springs had worn through and was metal to metal. I just put some coil spacers in to fix it, but some heavy duty rubber would do the same thing I would think.

[duck]

check your rear sway bar, get under there with a rubber hamer and hit it up and down, should make a kocking sound, mine dose it and im to lazy to change the bushes, its gotten to the point it will just knock constently when driving on tram tracks

[Sic Lux]

Floged out shockie rubber mine did it a little then really bad one day Hmm no rubber left also look at the top shock mount the 2, 14mm?? bolts may be loose.

[thomasando]

Check out the exhaust - I have a custom system in mine following the path the factory one takes so it's a tight fit. I had 2 broken rubber mounts so the whole lot was floating on one, and it was the same as you describe - short sharp bumps has a metal on metal clunk. Took me a long time to find out it was the exhaust hitting the cross member just forward of the rear wheels (it has been happening for a few months, only discovered it in the last week). Definitely worth a look - 2 new exhaust hangers cost me $17.50 and the problem is gone.

[BLC]

Floged out shockie rubber mine did it a little then really bad one day Hmm no rubber left also look at the top shock mount the 2, 14mm?? bolts may be loose.

Turned out that this seems to be the problem. Bottom bush on the shocky is rooted. Are these a generic replacement? or is it something I will have to match up?

i.e. will Repco have this on the shelf?

thanks again for the replys

Nik

[80's_delirious]

Floged out shockie rubber mine did it a little then really bad one day Hmm no rubber left also look at the top shock mount the 2, 14mm?? bolts may be loose.

Turned out that this seems to be the problem. Bottom bush on the shocky is rooted. Are these a generic replacement? or is it something I will have to match up?

i.e. will Repco have this on the shelf?

thanks again for the replys

Nik

had the same thing with mine. local auto parts had a generic replacement for a few bucks each, just take one in with you to match it

[toaddog]

You might as well do all of them at the same time. Not a real big job.

[BLC]

Floged out shockie rubber mine did it a little then really bad one day Hmm no rubber left also look at the top shock mount the 2, 14mm?? bolts may be loose.

Turned out that this seems to be the problem. Bottom bush on the shocky is rooted. Are these a generic replacement? or is it something I will have to match up?

i.e. will Repco have this on the shelf?

thanks again for the replys

Nik

had the same thing with mine. local auto parts had a generic replacement for a few bucks each, just take one in with you to match it

sweet as, yeah im gonna do them all at once

cheers for the info guys

Nik

[bj on roids]

Hi Nik

Loose baffles in sub tank perhaps? give the fuel tanks a good kick.

Place your hand on upper and lower control arm bushes and get someone to rock your car backwards and forwards in gear, you will be able to feel movement in bushes this way.
Might pay to remove and check panhard rod bushes too, they usually go first.

Good luck.

I have seen the loose baffles in the sub tank problem cause this, among other things. I was wondering if someone else would mention it. Other than the sway bars it was a great post.

[bj on roids]

Floged out shockie rubber mine did it a little then really bad one day Hmm no rubber left also look at the top shock mount the 2, 14mm?? bolts may be loose.

Fuel the rear tank up full, if it still clunks, replace all shockies.

[stilivn]

hey mate i had that prob with mine last week. When i put my 4" lift in looks like i didnt do the adjustable panard up tight enough an adjuster bolt came loose, all good now but.