There I was thinking old cars are easy to work on. I'm sure it would still be easier than fixing the climate control on one of todays cars. Especially in 50 years time when the plastic bits have turned to dust.

I broke the last post into paragraphs for readability, but the site compressed it all when I posted it for some reason.

that's pretty impressive that you rebuilt that valve! hope it continues to work. For those of us that have replaced one that's a big enough of an accomplishment in itself. As a lot of things tbird- either not cheap, easy or available. those valves are running over $60 in rebuilt condition.

       A  L  A  N   F  R  A  K  E  S   ~  Tulsa, OK    

After starting at both bumpers then working my way towards the middle I finally got the grasshopper valve out. After looking at it for a while to try and work out how it worked it was time to try and pull it apart. I managed to bend the tabs back and open it up without breaking anything and to my surprise the diaphragm and rubber seat were still in good shape. Now I can see how it works!
Clean and reassemble with a bit of rubber grease to help make sure it seals. Then one of the tabs breaks when being bent back over. OK pull it apart, cut a small strip of 1/16 sheet metal and solder in place (very fiddly). Reassemble and check. It's leaking past the needle and rubber seat when closed but found if I push the diaphragm slightly it seals. I think if the bimetal strip heats up a little it will do the job and close it completely.
Time to put some heat on and the wife's hairdryer is just the tool for the job. Suck on the end to simulate engine vacuum, OUCH that's hot, and still not working. As the bimetal strip moved and pushed on the end of the diaphragm the spring wouldn't hold it against the adjusting cam. OK put another turn on the wire spring to give it more tension, OOPS that broke. Found an old brush and spring from an alternator, so cut that off and straighten some and cut to length. Rewind and shape to look something like the original and hook in place. Back to the hairdryer, OUCH it's still hot, and still lifting off the cam. Still have a bit of that brush spring left, shape ends to hook on the arm and hook to the body of the valve. Test again, still hot, at last it's working properly!
Now all I have to do is put my car all back together.

Meandean On you question about the valve, the answer would be NO, it would not make any noise. Sounds more like the gate that directs the air either to floor or in the other position to the windshield some how flapping about or maybe something flapping in the fan blades. Haven't had to deal with the vacuum wipers as mine work fine, but I'm going to replace a lot of the vacuum lines before it goes back together as they're getting hard after nearly 60 years and are potential leaks. You my want to look at that to see if you are getting full vacuum.

I'm not getting any vacuum to the manifold valve, so suspect it is what you are calling the grasshopper valve under the dash that is not working. I'm hoping access isn't too difficult.

I noticed the last time I drove my 55 Fairlane 272 Fordomatic that the heater worked, then blew cold, then worked. I also on occasion heard a slapping sound similar to a playing card in the spokes of a bicycle. Would this be the grasshopper valve in failure mode?

My wipers also don't work. They will go about 1/4 of the way up and stop there. I just figured it was a bad vacuum wiper "motor".

The manifold valve opens under vacuum, but be aware the grasshopper valve under the dash often fails, passing continuous vacuum to the manifold valve. I have a hand vacuum pump I use to hold the manifold valve open when flushing the cooling system.

6 VOLTS/POS. GRD. NW INDIANA

I am trying to get my heater working correctly and was wondering when the vacuum thermostat on the intake manifold was open to allow water to circulate through the heater core. Is it open when there is vacuum or when there is no vacuum?