clunking noise - right side front suspension

[ryanpe56]

I have a dull clunk noise coming from the front right side of my 1971 280SL automatic. After making a modest right hand turn (like a roundabout) and return the steering wheel back to center I hear a low level clunk on the RH side however, I don't hear it on a full 90 degree right hand turn or turning left to center. This car is mechanically original and has 145,000+ miles on it. I've checked over the suspension but I'm not familar with the MB design. The suspension components rod ends and steering box all look solid and the wheel bearings checked and good. All zerks have been greased except for the RH side top of the pin (that the spindle is attached to spans the upper and lower control arms) which won't accept any grease.

[roymil]

The most obvious suspect is the rubber subframe mount.  As you say, the car is mechanically original then it may not have ever had the subframe mounts replaced and if not, they will almost certainly have failed and that can allow vertical movement of the body relative to the front suspension that might certainly cause some noise...like a knee with no cartiledge.  If you search the site with keyword phrase "rattle on right front" or "subframe mount" you will find good posts including this link from several years ago with explanation and instructions on how to easily check.   

https://www.sl113.org/forums/index.php?action=post;topic=35535.0;last_msg=259516

[rwmastel]

I have a dull clunk noise coming from the front right side of my 1971 280SL .... All zerks have been greased except for the RH side top of the pin (that the spindle is attached to spans the upper and lower control arms) which won't accept any grease.

Roymil has a good suggestion, but also you might have already found the culprit.  This should be resolved, even if not the cause of the sound.

[ryanpe56]

I have it on my l4 post lift and if the subframe mounts that you are referring to are on the top side of the coil spring, then they look good. I too the weight off of the front suspension and I didn't see any change relative to those mounts. I changed out the king pin grease zerks and now they both took grease...and a lot of it! I'll take it out for a spin and see if that helped any. Thx

[rwmastel]

I changed out the king pin grease zerks and now they both took grease...and a lot of it!

Awesome!

... and if the subframe mounts that you are referring to are on the top side of the coil spring, then they look good.

Subframe mounts.
https://www.sl113.org/forums/index.php?topic=36342

[Jack the Knife]

I had this issue on my old BMW F82 M4 and it was the subframe mount but sounds like you might've worked it out. Clunking sound only when I made a gentle low-speed turn.

[ryanpe56]

I hope that not my problem as it looks like a big job to replace them. Yeah, mine also makes the sound on low-speed turns as well. Thx

[ryanpe56]

Thanks for the pics!  The old (compromised) mounts are not very noticeable in chassis until you put them next to the new ones on the bench!  Great info.

[rwmastel]

I changed out the king pin grease zerks and now they both took grease...and a lot of it! I'll take it out for a spin and see if that helped any.

Test drive yet?