Rattle 'tinny' metal-on-metal 'clunk' when going over bump

JohnCleary · 08-10-2014 4:00pm #1

Hi all,
2008 Merc C220 diesel auto Avantgarde

With the drivers door open (right hand drive), when I go over a bump, I notice what sounds like a metal-on-metal 'clunk'. It's definately coming from the rear right-hand-side (not sure about left hand side) wheel area as the noise only happens when the wheel itself goes over the bump.

I'm at a total loss as to what it would be. It's definately an issue as it's gotten slightly worse over time (1 month). I cannot hear it with the window closed and I don't feel the sound come through into the cabin. Someone said it could be a rear drop-link bush gone (are there rear anti-roll bars?)

On a possibly related note, between 40kmh - 50kmh, the car starts to wobble from side to side. It's very noticable as my legs start wobbling from side to side. Again, this appears to have gotten worse over time so possibly related? Someone said it's most likely a warped alloy or a wheel off balance, but thought i'd ask here. It only shows between the speeds mentioned above.

I went out and had a quick look under the car and in the centre of the rear of the rear subframe, I spotted the bushes are totally wrecked on this item:

Here's a video:

https://www.youtube.com/watch?v=aGFeWwBOIog

What is this component? Either way it needs changing. I'm just worried the subframe will have to be dropped to replace it.

And finally, would this cause those symptoms?

Thanks all

JohnCleary · 08-10-2014 4:24pm

I think it's the diff mounts, but not certain.. hence asking

dgt · 08-10-2014 7:48pm

If the car is swaying, have a look at the subframe mounts, they are often gel filled. They can go maggoty with age. More than likely it is the diff mount (arm in need of replacing in vid)

As for your tinny sound, it might be a heatshield as mine can hit speedbumps (although I have a much older and much lower car)

Rattle 'tinny' metal-on-metal 'clunk' when going over bump

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