To continue my earlier comments, let me suggest that you think of the VCV as a "controlled vacuum bleeding device"... or put another way it is a "variable bleed" dragging down the vacuum supplied to the Engine/Tranny vacuum control system and this bleed is coupled to the throttle mechanically. In the earlier control systems and as I see it on all model's control systems [except the 1985 CA configuration]... to me it is obvious that the VCV is set to always be dragging down the vacuum at all times and as the throttle increases, the bleeding increases and drags down the vacuum more and more. So YES, it is entirely normal for the VCV to appear to be leaking IF you test it off the vehicle. This is why MB devised special test equipment to test and adjust the VCV... but in my opinion the test/adjusting equipment is NOT really necessary and probably discourages many to not think this IMPORTANT control system [ "Engine/Tranny Vacuum control System"] through and understand what it's doing. I have found and thus formed the opinion that IF you can get your VCV adjusted close enough, then you can do the final "tweaking" by using the cheap restricted orifices. There are several of these on these later model cars.

By the way, IF you make the mistake and drill out the vac.pmp-to-brake booster "Tee" too large, it's quite easy to put an inline restricted orifice in the line that is connected to the "Tee". IMHO, the main reason for the restricted "Tee"s branching off this main vacuum line was to insure that the vacuum brake system would not loose too much vacuum IF the Engine/Tranny system suffered a catastrophic rupture in one of it's vacuum lines... and this theory is supported by the fact that in the 126 and other later models, MB, added a separate electrically powered vacuum pump for the door-lock system!

IF either of you have a VCV that you canNOT see how to adjust, let me know!

I've also started working on the 1985 Calif Vacuum Diagram, adding color so you can readily tell vac from electrical and subdividing the system into sub-system(s). I canNOT read the colors on the PeterSchmid diagrams so I will use my father-N-law's Calif '85 W126 to pick off the colors for both vacuum lines and the electrical wiring!

Regards,