Cannot speak from experience but there is a solid-state electronic replacement for the old-type servo ACC that I think you are referring to -- you didn't mention the year of the 300D your are looking at. It is expensive, about $700, I think, but apparently works well. My mechanic just put one in a 1970s SL and he reported that the customer liked it.

The latest version (ACC III) is easier to repair and less expensive, or so I have read here. I wouldn't let the servo alone dissuade me from buying that car (but the lack of a turbo would ).

Jeremy

__________________

"Buster" in the '95

Our all-Diesel family
1996 E300D (W210) . .338,000 miles Wife's car
2005 E320 CDI . . 113,000 miles My car
Santa Rosa population 176,762 (2022)
Total. . . . . . . . . . . . 627,762
"Oh lord won't you buy me a Mercedes Benz."
-- Janis Joplin, October 1, 1970