A footnote to this long and helpful thread. If you do this on a 90 or a 91, and as a result disconnect the vacuum line to the passenger side of the engine compartment, make sure you block off the line on the passenger side that goes to the vacuum reservoir....otherwise you will unintentionally leave a leak in the vacuum system. This issue is moot effective production date 06/91 with MY92, when the vacuum reservoir was eliminated.

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14 E250 Bluetec 4Matic "Sinclair", Palladium Silver on Black, 159k miles
06 E320 CDI "Rutherford", Black on Tan, 179k mi, Stage 1 tune, tuned TCU
91 300D "Otis", Smoke Silver on Tan, 145k mi, wastegate conversion, ALDA delete

19 Honda CR-V EX 77k mi
Fourteen other MB's owned and sold
1961 Very Tolerant Wife