Up to this point, any vacuum problems I've had on my 91 and 92 have been easily diagnosed by noticing loose hoses. But now I need to make sure I master some basics.

On the 91, the headrest that took a while to snap back (though it eventually did) and some minor tranny thuds are clear indications of some sort of vacuum problem.

Can anyone point me to the equivalent of "Vacuum Diagnosis for Dummies" or give me some basic advice? I assume I start with the source (the pump) and then work downstream. If the pump is fine (original with 112k miles), then that means that some hose or device is leaking....and that somehow I begin to isolate different sections of the vacuum system to find the culprit.

It looks like the Diesel Giant page is a good starting point for me. Mercedes Vacuum Troubleshooting

Any help much appreciated...thanks.

__________________
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