[Red Box Rebel]

I originally posted this in the Heating and Cooling Tech section, but I did not receive a single answer. So, I am trying the 68 GTO Section to see if anyone cares about the stand alone parts unique to the 68 GTO:


1968 GTO with original factory A/C. The A/C and Heater selector controls a ported vacuum switch that routes vacuum to blend doors and other A/C and Heater components.
Vacuum comes into the disc shaped ported vacuum switch and is supposed to direct vacuum based on where the selector is set to. As the selector is moved up from Off:
1.Off
2. Vent
3. Inside
4. A/C
5. B/L
6. Heat
7. Defrost

On the ported vacuum switch are six vacuum ports. The vacuum in from the intake manifold and five ports for opening and closing the blend doors.

With the selector in the off position, the ported vacuum switch mechanism is able to hold 15 In.Hg. With all five of the other ports sealed off, when the selector is moved to any of the the other port positions from off, vacuum drops to zero. I assume that the ported vacuum switch has some internal seal that is no longer able to hold vacuum as the vacuum is directed to the five ports.

My question: Can the ported vacuum switch be repaired? Can the ported switch be replaced by a new one? Does anyone offer a repair and/or restoration service for this "Unique to 1968" Ported Vacuum Switch?
The original factory ported vacuum switch is 52 years old, so I am not surprised that is not holding vacuum any longer.
Anyone else run into this problem?

[nytrainer]

Subscribed

[68gtoMN]

I don't have an answer but I have many 68 dashboards with the switches installed. I believe I have several with AC controls. You're talking about the ports on the switch (behind the dash), correct? Perhaps I can check my parts to test this weekend.


Let me know if my assumption is correct


Kurt

[Red Box Rebel]

Yes, this is the A/C and Heater Control that is located directly behind the dash.

If you can check the ports for airtight integrity I would be very grateful. Thank you

[nytrainer]

Red,
Did you ever sort this out?

[dataway]

Just want to add a note. I did a lot of vacuum testing with a small pump and gauge on this system along with the headlight system. When checking vacuum while operating the switch, give plenty of time, maybe as much as ten seconds for the vacuum to come back up after switching. Depending on the position of the switch it might have to operate a couple of different actuators .. some very small orifices in some of them, takes a moment for vacuum to come back up even if there is a good seal.