The Org
Serving W116 Enthusiasts since 2004!

Main Menu

Help troubleshooting rear suspension noise

Started by Rolo, 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.



You need to add your specific model to your signature and this thread so we know which model you are referring to.
1977 450 SEL 6.9 - Astralsilber


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.
W116 1977 280SEL & 1979 280SE
[img width=150 height=100][url=""][/url][/img]


190sl 1957 rusting away
250S 1968 long gone
280SE 1976 got hit, parts
280SE 1979 running fine
C320 4Matic 2005 for wife -Mercedes after MIT


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.
1979 300 SD "Liesel", 269k Miles


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. 


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.
1977 450 SEL 6.9 - Astralsilber


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.
1979 6.9 #6475


1977 450 SEL 6.9 - Astralsilber


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.
1979 6.9 #6475