Bob is right it is not supposed to have a vacuum leak on that shaft. I see you are from the northeast like me and use your heat at times? I am not sure if you are aware, but you are one of the lucky first gen owners whose car comes with a hot water shutoff valve, 69 birds with a/c only. The rest of us first gens did not rate even though the more expensive models in the lineup had been using them even years prior. The reason it's so great and why all cars after about 71 used them is it keeps the cabin cooler in the summer because even though the blend doors close off the hot air from blowing into the cabin you still end up with the core and the whole case under the dash at full engine coolant temp which of course is just like a convection oven under the dash. The reason I went through that lengthy explanation is because if it were me, I would want to keep the hot water valve in the system. The problem with the control valve leaking is the gasket or O-ring is dried up or broken and finding a good used one as you found out will be a crap shoot and I don't think they are available in the aftermarket, at least a direct fit. The simplest thing you could try is to put a drop or two of oil at the top of that shaft and let it soak in good and if the seal is not too bad it may swell and seal. It's a long shot but easy to try so why not. The second thing to try if you are handy and really want that controller to work is to un peen the end of the shaft of the worst of the two you have and see if you can replace the seal inside or find an auto hvac co. that would be willing to do it for you. To me the easiest solution if you're not putting the a/c back into the car is to plug the vacuum line to that valve and just manually plug and unplug vacuum to the hot water valve under the hood when you want heat which would mean If you used the car in the fall just leaving it in the heat position and in the summer in the off position. Of course, if you don't care about the hot water valve at all you can just eliminate it and deal with the extra heat in the summer like the rest of us peons have to.