Tee-Bird Products is the only One who listed an Exchange Valve. I just heard back from them. The Man who was reconditioning them has been unable to get correct Diaphragms recently so no Valves are available. I guess I have to go with NOS and take a Chance. .

  

I'd be more tempted to buy a rebuilt unit simply because of them using more modern diaphragm material versus 50+ year old "original" material that could be rotten or brittle by now.

Regards, JLB

55 Ford Crown Victoria Steel Top

There's more to this little valve than it first appears. I assumed it was simply a Mechanical only Valve to Control Coolant Flow to the Heater. The Lever moves fine but as U indicate there could still be seized or damaged Diaphragm inside. Thanks for theInfo.

  

I freed mine up about 8 years ago. The memory is a bit fuzzy on it.
 I carefully opened it up and the pin had seized. 
The diaphragm  was good so I cleaned up the pin and used rubber grease as it controls the amount of vacuum going to the diaphragm by pulling the pin out of rubber with a hole through it. The pin is moved by a bimetal strip to regulate vacuum. 
It was fiddly but if you have the patience it can be done.

Thanks for the Info. There are several NOS original Ford Valves for sale on Ebay. Whats your Opinion  re buy NOS or Buy an Exchange Unit?

  

Yeah, diaphragm is most probably cracked/broken. You wouldn't know for sure unless you take it apart.  I've carefully pried the seals on those types of  manufacturing & sometimes you can put them back together by re-crimping after "fixing" [when possible]; which is probably what the "exchange" people do [by putting-in a new diaphragm of modern materials].

Good luck, JLB

55 Ford Crown Victoria Steel Top

Very helpful. The Cricket Valve moves up and down freely. It was hooked up when I bought the Car but I don't know if the Heater Control was actually working. Rubber Lines to the Windshield Wiper Motor were falling apart which is T'd into the Heater Control Line. I guess the Diaphragm is gone in it. Lots of Vacuum in but very little out even in the full open Position. They seem to sell a lot on Ebay and they are also available as "exchange" rebuilt from a couple of Parts Sellers. In the full open Position I assume Vacuum should pass through equal to whats going in to  open the Valve on the Intake Manifold?

  

There's a diaphragm in the "cricket valve" ; and, one in the manifold valve.  Another possibility: Sometimes the valve "shaft" gets corroded "in-place" and, simply, will not move.  I've had this happen in other similar applications.  Carefully work it loose, a bit at a time [if you can], with a small amount of silicone grease [the clear "stuff" used for electrical connectors, spark plug wires, etc.] into the shaft/seal area until it works smoothly.

Hope this is helpful, JLB

55 Ford Crown Victoria Steel Top

Casco sells a kit to change the vacuum heater control valve to manual.  It's made for a 55-57 TBird, but may fit other cars. 

Are You referring to the "Cricket Valve" in the Heater Box or the One in the Manifold? The One in the Manifold is new. I haven't installed it yet. I wanted to make sure the Valve on the Heater was going to allow Vacuum through it before I took out the Manual Control Valve I have in the Manifold now. Should that "Cricket Valve" allow Air  through when I test it using Compressed Air? Right now nothing goes through in any Position on the Dash Temperature Lever.