When I make a sharp right turn the front left wheel makes a low pitch rumbling (grrrrrr). I replaced the wheel bearing but this did not help. The noise only occurs under hard cornering and only when turning right. There is no obvious play in any of the bushes or bottom balljoint. I also sometimes experience some juddering when braking.

300se manual 1987

W126 front noise
 

See my post (and the related answers) on 4.10.01 (try link

http://www.peachparts.com/shopforum/tech-help/16235-w126-front-suspension-noise.html

I replaced the lower ball joints and the guide rod mount (kit is part no #126-330-13-35) -- also known as castor rod joint -- and it solved my somewhat similar problem. Labor at an independent was $260 for both ball joints (I did both sides) and $260 for both guide rod mounts. Dealer labor would have been $316 and $308 for the same work. Parts were $25 each for the ball joints and $62 for the guide rod kits.