Need Heat / AC Dash Part

[dpoepperling]

Looking for the Rotary vacuum switch for the dash controls for a 73 with ac. I have 2 and both are broken. Looking for used, as I am not going to spend what it costs for a new one.

[email protected]

 

[marks73]

Hell, I can't believe I beat Roy to one.

:worthlesswithoutpics:

 

[LCB1]

Hell, I can't believe I beat Roy to one.

:worthlesswithoutpics:

He's still trying to figure out what to wear tonight

 

[marks73]

Hell, I can't believe I beat Roy to one.

:worthlesswithoutpics:

He's still trying to figure out what to wear tonight

rofl Timing IS everything!

 

[dpoepperling]

Ass....

 

[marks73]

I do have a few spare parts on the extra I have. Just not sure which your looking for. I apologize for getting caught up in other posts as it relates to this one. Let me know.

 

[dpoepperling]

It is behind the a/c - heater controls....plastic, has the ports where the vacuum hoses connect to. Does that help?

 

[marks73]

It is behind the a/c - heater controls....plastic, has the ports where the vacuum hoses connect to. Does that help?

Is there a way to test to see if they're good? I'm going to need 1 of them on my car.

 

[c9zx]

I tested mine with a Mighty Vac, vacuum diagram, and some caps. Inside of the vacuum switch is a circular rubber vacuum routing "gasket" that has raised edges that looks like an English maze. Mine was bad and causing a small vacuum leak. I remember taking it apart, applying silicon spray to the rubber and plastic parts and fastening it back together a screw where a "rivet" had been. The pressure exerted by the screw had to be just right to get it to seal and still allow the switch to move easily. My memory is a little fuzzy on the details. In any case, I got lucky and it worked. 70-71 the vacuum switch is metal but they seem to be no more reliable. Chuck

 

[marks73]

I tested mine with a Mighty Vac, vacuum diagram, and some caps. Inside of the vacuum switch is a circular rubber vacuum routing "gasket" that has raised edges that looks like an English maze. Mine was bad and causing a small vacuum leak. I remember taking it apart, applying silicon spray to the rubber and plastic parts and fastening it back together a screw where a "rivet" had been. The pressure exerted by the screw had to be just right to get it to seal and still allow the switch to move easily. My memory is a little fuzzy on the details. In any case, I got lucky and it worked. 70-71 the vacuum switch is metal but they seem to be no more reliable. Chuck

So, do you recommend taking it apart for inspection? Like I said I need to make sure I have one for my car that is good.

 

[c9zx]

Check it before taking it apart. It may be good, it could happen. It is a bit tricky as I said. I've got the port function identification drawing some where. Let me know if you, or anyone else, needs it. Chuck

 

[marks73]

Check it before taking it apart. It may be good, it could happen. It is a bit tricky as I said. I've got the port function identification drawing some where. Let me know if you, or anyone else, needs it. Chuck

I'm thinking I would have to have a dash in the car first. How do I test it out of the car?

 

[c9zx]

Check it before taking it apart. It may be good, it could happen. It is a bit tricky as I said. I've got the port function identification drawing some where. Let me know if you, or anyone else, needs it. Chuck

I'm thinking I would have to have a dash in the car first. How do I test it out of the car?

Attach the mighty vac to the 4th port from the left as viewed from the front and top (black hose that comes through the firewall when installed).

Cap the other 5 ports, apply 15-20 in.hg. and see how fast the vacuum leaks down.

To test individual ports keep the vacuum source where it is, cap the 4 ports you don't want to check, and attach your trusty vacuum gauge to the port you do want to test. Apply vacuum, and see if it leaks at the same rate as in the first check. If it leaks the same it is a general leak of the vacuum switch as as whole. If it leaks faster it indicate a leak/crack in that port.

Color coding on hoses, left to right: white, brown, red, black, blue, yellow.

A 7th hose that passes through the firewall with the black hose is color coded purple and attaches to the water valve vacuum switch located on the heater/AC box close to the blend door crank arm.

Under the hood the black hose attaches to the small nipple on the vacuum canister and the purple hose connects to heater control valve.

Chuck

 

[marks73]

Check it before taking it apart. It may be good, it could happen. It is a bit tricky as I said. I've got the port function identification drawing some where. Let me know if you, or anyone else, needs it. Chuck

I'm thinking I would have to have a dash in the car first. How do I test it out of the car?

Attach the mighty vac to the 4th port from the left as viewed from the front and top (black hose that comes through the firewall when installed).

Cap the other 5 ports, apply 15-20 in.hg. and see how fast the vacuum leaks down.

To test individual ports keep the vacuum source where it is, cap the 4 ports you don't want to check, and attach your trusty vacuum gauge to the port you do want to test. Apply vacuum, and see if it leaks at the same rate as in the first check. If it leaks the same it is a general leak of the vacuum switch as as whole. If it leaks faster it indicate a leak/crack in that port.

Color coding on hoses, left to right: white, brown, red, black, blue, yellow.

A 7th hose that passes through the firewall with the black hose is color coded purple and attaches to the water valve vacuum switch located on the heater/AC box close to the blend door crank arm.

Under the hood the black hose attaches to the small nipple on the vacuum canister and the purple hose connects to heater control valve.

Chuck

That easy huh? No wonder I hated HVAC all my life.

 

[c9zx]

Yep, it's that easy. I'm glad I could insire you to jump right on it . I don't particularly like working on HVAC either. Chuck

 

[dpoepperling]

I was able to fix what was broken. It is actually more sturdy than it was originally.

Just finished rebuilding my heater/ac box and reinstalling it. It was a bit of a chore, but well worth it.