It may be a stretch to refer to us posters in Open Discussion as gentlemen. However, your question will be best answered on the diesel discussion. The vacuum tank is in the trunk. You'll need a Mity Vac to trace down the problem. On the 240d, the most likely culprit is a vacuum pod in the locking system somewhere. What are your symptoms?

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1977 300d 70k--sold 08
1985 300TD 185k+
1984 307d 126k--sold 8/03
1985 409d 65k--sold 06
1984 300SD 315k--daughter's car
1979 300SD 122k--sold 2/11
1999 Fuso FG Expedition Camper
1993 GMC Sierra 6.5 TD 4x4
1982 Bluebird Wanderlodge CAT 3208--Sold 2/13