[tallrandyb]

Originally Posted by aceaceca

My 65 is an original family owned car. The AC renovation I am currently doing is one of the last systems on the car that I have not done. This time, I had both inner and outer plenum boxes off the car. I replaced the two inner vacuum motors on the inside. One opens the defrost door and the other one controls two doors in tandem. It swings a door to divert the incoming air from the evaporator so it does not go to the heater core and at the same time opens the door to direct air to the AC outlets via a secondary plenum box that attaches to the front of the heater/AC plenum. The two doors are connected via a long rod on the top of the heater plenum box.

Ace, reviving this thread and to see what you might remember and/or what anyone else knows (anybody up for a deep vacuum system discussion?).

I've got my dash apart and am checking the vacuum system. The 5 vacuum lines to the dash switch are numbered in order 1-5, and I'm trying to make sense of which lines are pulling vacuum on which diaphragm. Attached is a markup of the 65 vacuum system with my notes.

My statement at the top that the (1) vacuum circuit somehow also feeds vacuum to the (5) circuit is clearly wrong, since the Evaporator (1) (AC) door is controlled by the bar connected to the Diverter (5) (Vent) door.

I know the Defrost (4) door is controlled by the diaphragm by the drivers feet (mine is dead, confirmed with vac pump).

So what does vacuum line (1) actually pull on? 1 and 2 both go to the diaphragm in the engine compartment. If I pull vac on 1, that works fine (but I don't see anything move). If I pull vac on 2, I don't get vac (like a dead diaphragm). BUT, if I block 1 (at the switch) and then pull vac on 2, I see the diaphragm pull in the engine compartment, and I'm assuming that is moving the inside/outside air door.

So when vacuum is applied to vacuum connectors on the switch:

1: what does vacuum pull on? This and 2 both go to the engine compartment diaphragm. I originally thought this had to be the AC evaporator (deflector) door

2: inside/outside door (when hose/connector to port 1 is sealed off at switch)

3: engine vacuum feed (with one-way check valve)

4: Defrost door

5: Vent (diverter) door that also moves Evaporator (deflector) door

Thanks for any help/discussion! My AC is working well, blowing cold when switched on, etc so it appears at this point that all diaphragms are working except the Defrost door, but I can't see how to remove/replace that without removing the entire heater plenum? Good thing I live in Florida!

Thanks.