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Garage => Mechanicals => Topic started by: Rolo on 05 April 2022, 02:53 PM

Title: Help troubleshooting rear suspension noise
Post by: Rolo on 05 April 2022, 02:53 PM
I've had a clunking sound coming from the rear.  It's been there for 30 years, but I thought while we're doing some other work, it might be time to deal with it.

It sounds almost as if something is banging on the rear firewall  Comes from the left side.  Thunk, thunk over small sharp bumps at low speed.

Hints?
Title: Re: Help troubleshooting rear suspension noise
Post by: daantjie on 05 April 2022, 03:09 PM
You need to add your specific model to your signature and this thread so we know which model you are referring to.
Title: Re: Help troubleshooting rear suspension noise
Post by: revilla on 05 April 2022, 03:18 PM
Your fuel tank is held by 4 nuts at its base. I had a similar noise long time ago. One of them might be loose causing the whole assy to bounce/bang. Or the panel covering the tank typically becomes loose in one of its corners. Or the cable to the sending unit bouncing against the top of the tank. It should have a foam ring that doesn't longer exists or it's misplaced.
Title: Re: Help troubleshooting rear suspension noise
Post by: polymathman on 06 April 2022, 01:17 PM
Check shock mounts.
Title: Re: Help troubleshooting rear suspension noise
Post by: amilio on 08 April 2022, 12:54 PM
I would say it's probably your rear sway bar links. Had both go bad on mine and it was a similar sound. Was worse when turning when it would bang on the metal brake cover. Easy DIY repair. Part No: 115-320-15-89. I went with Meyle as opposed to OEM and no issues now almost a year later.
Title: Re: Help troubleshooting rear suspension noise
Post by: Rolo on 14 April 2022, 03:42 PM
It's a '77 6.9.  I did strut mounts and that wasn't it.  It's not metal-on-metal.  A duller thud.

But gas tank sounds promising. 
Title: Re: Help troubleshooting rear suspension noise
Post by: daantjie on 14 April 2022, 04:24 PM
I second to check out the sway bar for possible worn out mounts as well as the shackles where it connects to the wheel carrier.  This is part of the "anti squat" system and there are rubber bits that are likely well past their prime.
Title: Re: Help troubleshooting rear suspension noise
Post by: Mick74 on 16 April 2022, 06:15 AM
I'm just after getting an evaluation of my car and, among the myriad of issues, were the following:

Rear subframe bushes - weak/delaminating.
Rear anti roll bar D-rubbers and end link bushes - perished.
Rear figure eight link bushes perished.
Strip and inspect lower rear bushes/pins with above removed. (squeaking noise ).

The car is a 6.9 and has an irritating creaking noise, which is probably caused by the above.
No banging noises, though. I'm getting all this done, along with the other stuff, as mine is a driver, rather than a show car, so I want it to be right. I'll upload photos as we go along, as I'm interested to see how bad the bushes are when they come out.
Title: Re: Help troubleshooting rear suspension noise
Post by: daantjie on 16 April 2022, 12:05 PM
Quote from: Mick74 on 16 April 2022, 06:15 AMRear figure eight link bushes perished.


What are these?
Title: Re: Help troubleshooting rear suspension noise
Post by: Mick74 on 12 June 2022, 10:58 AM
Sorry for the late reply, daantjie. I've been off site for the last few weeks. To be honest, I don't know what those bushings are referring to. I assume that that is just the description that the mechanic gave them. It may not be accurate to what the bushing actually looks like. The plan is to remove the rear suspension and replace every wearable part possible. I will get photos of what is coming out and going in, so that may clear it up.