Thanks for the input Jim, I tend to agree with you somewhat. I replaced the tires recently; they had about 50,000 miles on them, and despite the slight clunking, the tires were worn evenly with no feathering or other irregularities (the clunking had been there at least a year or so and maybe 15,000 miles before I got the car from the previous owner). The alignment is obviously very tight, so I believe the play is likely between the pinion gear and the rack itself. I guess it just bugs me that the play is occasionally "noticeable." Had there been no occasional clunk I wouldn't be worried.

Interestingly, before I bought the car I had the PO take the car to the dealer for some other issue, and I recall them quoting him a price for ball joint replacement which they diagnosed as causing the slight clunk. But they were obviously WAY off. The ball joints are fine.

I only notice the clunk every once in a while, but when it occurs it almost feels like play in the tie rods. There are no handling issues and no binding or resistance. New Michelins are wearing evenly, too. You're right - I should probably just not worry about it.

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08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280