Check the front tires for wear (esp. cupping on the inside or outside edge of the tread). When was the last time you had an alignment? If the tire has started wearing funny it will make a hell of a lot of noise down the road. This is usually indicative of tie-rods etc in the front end.

I had to go through all that on my w124 a while back. It turned out to be the tie-rods (which I replaced) and the control arm bushings (which the dealer had to cut off w/ a torch...that was pricey...). All fixed now, though.

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Currently:
1972 350SL Euro 4spd
1973 BMW R75/5
1981 BMW R80GS
1995 FZJ80 with OM606 Conversion In Progress