Alon, I remembered you told me to tighten the disc, but it doesnt really do anythign considering that you tighten your lug bolts down to 80 ft. lbs or more. Mercedes recomends 80, but I always do 90. It shouldnt do anything by tightening the disc, but I guess it does because it did work a little.
You may want to check the brake pads because they could have gotten cocked inside the brake pad bracket.
I have been fighting the same problem, but when you put on the brakes. Do they squeal when you are about to stop?
My car needs wheel bearings. Im going to do that this weekend, so Ill let you know if it fixes it.
Id try what alon suggests, then if that doesnt work. Let me find out if the wheel bearings fix it.
Since you will have the wheels off anyway, take off the calipers, and put antisieze on the edges of the pad and on the back maybe its binding / stuck on the pistons.
No Benzes in the stable at the moment, but itching for one again.
Former Mercedes in the Stable:
1983 300CD Turbo diesel 515k mi sold
1984 300CD Turbo Diesel 150 k mi sold
1982 300D Turbo Diesel 225 sold
1987 300D Turbo Diesel 255k mi sold
1988 300 CE AMG Hammer 15k mi sold
1986 300E Amg Hammer 88k mi sold
1992 500E 156k mi sold