Strange vibration W209 CLK 320 cdi

[mymelt8]

Hello everyone. I have a problem with vibration that has been developing over the last few months.
It becomes apparent at about 50mph and increases progressively from there. At first I thought the rear wheels needed balancing so I had them done twice to be sure. No improvement. I then replaced the tyres with a different make ( off with the Dunlops and on with Michelin ) with no improvement. It is getting worse and feels like a faster vibration than a wheel balance issue to be honest. It doesn't make any difference whether the car is under acceleration, neutral or coasting. The vibration stays the same. Any ideas?

 

[grahamcol]

Not sure which Merc you have but assuming it's a rear wheel drive vehicle it could be propshaft or prop centre bearing perhaps.

 

[LostKiwi]

I'd look at the rubber drive couplings. There are 2 - one at the gearbox and one at the differential.
Any sign of cracking replace them.

 

[M80]

As above look for worn bushes, play in couplings.
Drop the prop shaft and check uj's for resistance and clicking and bearings for play.
Strip rear brakes and check 'hand' brake shoes for security / binding, and pads aren't tight in their slides and that the calipers can travel on their slides. Are the discs running true and without chunks removed from rust around the circumference?

Is there any chance a wheel isn't seated correctly or has been knocked out of true?

Really it's elimination, as you have started to do, until the fault is cured.

 

[mymelt8]

Thanks guys, I'll report back when I've got to the bottom of it.

 

[Mikeclk320]

Hi Mymelt8 - did you ever get to the bottom of this? I've just bought a CLK320 which seems to have the same problem

 

[Wighty]

Hi Mymelt8 - did you ever get to the bottom of this? I've just bought a CLK320 which seems to have the same problem

If you bourght it from a dealer/trader , get them to do it under warranty