My 1988 Mercedes 420SEL has a creaking noise comming from the right front suspension. The noise started as a slight noise but quickly has changed into a rather embarsing creak you can hear for quite a distance. The sound is like a boat scraping against a warf, more of a metal-rubber noise than metal on metal. But, mostly loud and very offensive. I have tried lubercating the rubber bushings I can find with silicone spray with no success, I have often heard this type of noise in a number of older cars. Does anyone have suggestions? Thanks.