W202 clunking sound, rear

[anthonyb]

A few weeks ago I started noticing a clunking sound from the left rear of my C230K. It sounds like metal on metal, and it makes the sound when going over rough, uneven surfaces. Interestingly, it doesn't make the sound going over speed bumps or moderately rough roads. The periodicity sounds like something loose that's hanging down from somewhere - it makes the sound most often when the rear is moving side to side. My thoughts were sway bar links or a broken exhaust hanger.

The rub is - this weekend I took off the left rear wheel and stripped the left trunk liner, and nothing is loose. All the suspension bits seemed firmly attached (both hanging and at ride height) and the exhaust hangers are good. And nothing inside the trunk compartment seems loose.

Any ideas?

Thanks!
Anthony

[redcoupe]

Did you check to see of the rear sway bar endlink are loose. Not as the nut is loose, but loose as in when you push up on the bar at the endlink and you can feel it knock.

[psfred]

Check the rear subframe mounts (there are four) for deterioration and protruding mounting bolts indicating that the mounts have collapsed, allowing the subframe to contact the main body, or the retaining disks to contact the subframe.

Also, a bad bushing in the torque links will result in a hard clunking noise under the rear seat cushion, accompanied by torque steer from the rear (pulls one way on acceleration and the other on deceleration). You may get excessive right rear wheelspin on hard acceleration, too. Any sign of deteriorated rubber on any of the rear suspension links means it's time to replace them all.

Peter