So I checked the vac supply and it is delivering 21 psi, so I think that my pump is up to spec. I then noted the following leaks.

1. Vacuum pump to brake booster - leaks 5 psi per minute, apparently at the check valve. This is where I heard the buzzing before. I will take apart tonight, but I suspect that this part will need replacement edit (I ordered the part).

2. Null position of the HVAC pushbutton selector - 5 psi per minute. I pulled a vacuum on the aux line going from the pump to the HVAC system and checked each of the buttons. All held vac except when the O button was pressed. This is not the ultimate source of my hard shifting trans, because when I plugged the distributer to the HVAC, there wasn't any change to the shifting. (edit) I traced this to a main air flap vacuum element that had a ripped diaphram (I ordered the part).

3. Input line to the Vacuum Control Valve on the injection pump. This line will not hold vacuum and it bleeds off really quickly. Could this be the way that it is designed?

Does anyone have any ideas on which of these three leaks are real problems (especially numbers 1 or 3)?

thanks

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84 300TD - 235k - Farbe "Surfblau" bought at 213k
87 300SDL - 131k - Farbe "PimpGold" bought at 115k
00 Klepper Faltboot Expedition Double