Will do Joe.
Here's some pics of how I went about troubleshooting.
This is where I disconnected ALL other vacuum systems other than the trunk mounted reservoir and the ACC system:
The green/black line runs straight to the switch panel where the whole AC system branches off from. The yellow/black line goes back to the reservoir. The tee goes to the vacuum gauge. You can hook your mity vac up the way I have the gauge connected but the big gauge helps me see what's going on when I'm inside the car. The check-valve (or one-way valve) keeps the vacuum that is pulled on the reservoir and AC system from bleeding back through the vacuum pump. The grey line goes into the vacuum pump to brake booster trunk. The check valves in the main trunk also keep the circuits isolated and it's pretty easy to check them out.
I started with the reservoir and checked it with the mity vac. I then put the gauge on the tee and let the engine pump pull a vacuum on JUST the yellow/black (reservoir) line. Once that was OK and held vacuum for a couple of hours I hooked the green/black (AC) line up.
Before testing the whole system using engine power I checked all the circuits through the switch panel vacuum lines with this:
I then just checked each line by pulling a vacuum on them with the mity vac. Some of them bleed over to other lines at the switch panel so You'll have to study the diagram to see what goes where. I used a crayon to mark each line on the diagram as I checked it. When there were no leaks and the whole thing was colored I figured I was done
One of my trouble spots was here:
Most of the vacuum lines were leaking where the rubber lines hook to the plastic rectangular connector so I just CAREFULLY changed them out one by one. Probably not a bad idea to draw a diagram before starting because it was easy to knock several lines loose while working on one. It's like a friggin' maze
You can also use these lines as a source for pulling a vacuum for testing and plugging them to pull a vacuum from inside the car. Oh yea, don't try plugging with screws
It was driving me nuts until I realised that vacuum was leaking around the threads
The shank ends of drill bits worked best for me.
You can also have leaks here:
This valve appears to rely on vacuum to keep the rubber sealed against the metal part with the holes in it. (The rubber part is rotated by the servo motor while the part with the holes in it remains stationary.) The vacuum just "sucks" it together. I swear it looks like there is room for 4 springs under it to keep the discs pressed together but I didn't find any in either of my servos and they were both sealed... I put a light spring under mine and it solved a bunch of problems. My only fear is that it may wear out the rubber too soon.
This vacuum switch also runs the elusive center flap function. The center flaps aren't open when the system decides you need full heat. Turning the wheel from 85 down to 65 manipulates the servo which magically opens the center flaps after a short delay. Moving the wheel from 65 to 85 will close the center vents and change the airflow to the lower ducts. An electric "wiper" type switch in the servo adjusts the blower speed and probably does some other stuff that I haven't figured out
Sorry if this is long winded and I hope it makes sense! I'm not the sharpest cat on the planet and it took me several days to figure out enough of what I was doing to get anything done
I hope this helps someone get started and figure out some more stuff
I tested the system tonight after letting the car sit for a few days and all looks well. The reservoir pumped down to 15in/hg in about 5 minutes and only bled down to 10in after 45 minutes with the engine off. Manipulating the controls did bleed it down further but nothing caused any kind of instant "dump".