Dear Doctor: Don't know if this will help or not, but I have a 1990 420 SEL that i recently purchased and am repairing gradually, the first thing was the steering. My mechanic replaced the idle arm and did did some major front end work like the bearings, ball joints, gaskets etc. What a difference this made in the steering, it's so unbelievable smooth and precise I called and asked my mechanic if he gave me back the right car. Just my 5 cents worth.