[MBGraham]

When I took my 350SL out for first time this year , she ran perfectly, but I noticed a clunking sound when driving over bumps.

First, I tidied up trunk and made sure jack was properly clamped.

Noticed trim behind door on driver side low down was loose. Fixed that (screw had rusted out)

Tried driving with windows up and down. Noise virtually went away when windows were down. But back again as soon as I raised them. Repeated this several times with same results.

Removed door skin on driver side. Nothing loose! Checked glued on guides and they are still fine. Broke some clips getting skins off, so next job is to fix those. But hard to understand why lowering windows causes noise to almost go away.

Next possibility are Sway Bar links. Or maybe shocks are loose? No noise though if I bump car up and down in garage.

Exhaust doesn't make any noise if I jiggle it around.

BTW, soft top is up. May be back for more ideas

 

[dugald]

Is the top latched securely front and back?
Are those neoprene pads in place on the front top pinholes?

 

[cwmoser]

If it sounds like its coming from the left or right rear, it might be a broken/loose
drag link. My 380SL make a clunking sound especially when turning and
Rowdie diagnosed it for me.

 

[Fonzi]

My 1985 280sl sounds horrible in the rear end. Something ain't right back there.

As for the doors, is it possible that the window regulator is banging around?

Maybe the whole top mechanism is loose.

Does it make noise when window only half way up?

 

[tdoriot]

Same problem with my 380SL. Went thru everything. Got it up on the hoist, links perfect. NOTHING LOSE ! Finally boiled down to CV joints. Replaced both axles. Perfectly quiet no matter the speed of the roughness of the road. If you eliminate the obvious, then it's whatever is left. For me it was the CV's. I did a decent writeup if you decide to change them. Took about 4 hours and cost around $ 120 bucks all in. Unless you opt for the factory $ 600/ea axles that is :eek

 

[MBGraham]

Dugals asked:

Is the top latched securely front and back?
Are those neoprene pads in place on the front top pinholes?

Top is latched properly ( I store it partially latched, so had already fixed that). Don't know about pads, but noise is coming from rear of car. What I did notice, was that the boot lid was not properly latched. But have not driven it since.

Cmoser said:

If it sounds like its coming from the left or right rear, it might be a broken/loose drag link.

If drag link is same as sway bar link, then that is in my list to check.

Fonzi asked:

As for the doors, is it possible that the window regulator is banging around?
Maybe the whole top mechanism is loose.
Does it make noise when window only half way up?

Window regulator is firmly in place.
Top mechanism? Top is up and tight with no movement.
I only tried windows up or down for any length of time.

Tdoriot said:

Same problem with my 380SL. Went thru everything. Got it up on the hoist, links perfect. NOTHING LOSE ! Finally boiled down to CV joints. Replaced both axles. Perfectly quiet no matter the speed of the roughness of the road. If you eliminate the obvious, then it's whatever is left. For me it was the CV's. I did a decent writeup if you decide to change them. Took about 4 hours and cost around $ 120 bucks all in.

Hope it's not that. Is that using rebuilt or new half shafts? Kent Bergsma has a few good videos on subject (but I will check your writeup!)

Seems like W123 new 1/2 shafts are available in aftermarket, but not R/C107s?


Presently have to wait for epoxy to cure so I can put door back together.

 

[dugald]

.... noise is coming from rear of car.

This, you didn't say before.

 

[cushjbc]

I chased a noise like that around for a year. I finally figured out it was a worn, hardened bumper stop at the rear muffler hanger allowing the muffler to bang into the floor. A good test for this is to wedge one of those rubber donuts into the gap between the muffler and the center of the aft muffler bracket.

 

[MBGraham]

I chased a noise like that around for a year. I finally figured out it was a worn, hardened bumper stop at the rear muffler hanger allowing the muffler to bang into the floor. A good test for this is to wedge one of those rubber donuts into the gap between the muffler and the center of the aft muffler bracket.

I know the bumper you are talking about. I recall changing the donuts, but not that bumper, perhaps because I couldn't find one. Certainly something to check.

 

[MBGraham]

Checked the exhaust again. Rear donuts and bumper are fine.

But both mid muffler/resonator donuts are gone. Had just one spare, so installed it. (not easy with car still on wheels!). Have to order a new set.

Took car for a ride and the clunking was gone!

Could be as a result of boot lid now being properly latched or it could have been the muffler. I will never know

While under car, had a look at the axle boots. They look perfect despite being 42 yrs old. Also surprised to see all new bolts on rear flex joint. Shop that fixed front seal leak on tranny must have done that.

Anyway, at least got to check a few things and repair the door skin clips. And glad to see that the glued glass guides are holding up.

Thanks for the input!

 

[cushjbc]

I've gone through lots of those exhaust hangers in the 4 years I've had my car. I tried the H-shaped heavier duty ones and don't think they are any better in terms of durability - just more difficult to install.

I've never purchased the actual MB part. I think I'll try them to see if the rubber is better than what I've been using.

 

[MBGraham]

I've never purchased the actual MB part. I think I'll try them to see if the rubber is better than what I've been using.

I might try that route, but I bet they cost over $5.00 each in Canada.

 

[MBGraham]

I might try that route, but I bet they cost over $5.00 each in Canada.

Ordered four today. They had a square type that might have worked in stock but the broken one I had was an OE donut. He looked up number (1164920182) but it was no longer a good number. He ordered replacement number. Not sure what it was. Cost something just under C$5.00 each. Should have them tomorrow. Got them. Number is 1074920082. Name "damping"?? C$4.08.