Ledbelly

My 2003 CLK 320 W209 has recently developed a suspension squeak. It occurs mainly when turning left and appears to come from the right rear.
Interestingly it seems to go away in wet weather.
Is this a known problem and what can I do about it?

Any advice would be much appreciated.

Rudeney

Probably a dry bushing on one of the rear control arms. It may be hard to figure out which on it is. On a dry day where you can consistently reproduce the sound, you could try spraying them, one at a time, with WD-40 or similar light oil to see which one stops it.