I need a 20/80% vacuum valve for a 1964 Cadillac Convertible De Ville

I am hoping for some help --from my Cadillac guys

Been thru the regular channels --ebay -old air products --caddy daddy

Is there a place that rebuilds the vacuum valves ?

Any help locating this item is greatly appreciated
Will need a price quote



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Will be checking the valves before installing --thanks

Thanks for the heads up on the adjustable STV part - real nice feature
The direction i go --is not yet writen in stone --but i will go with R-12 if i can
I do like the idea of the 134a STV update controlling the compressors cycles as that ----saves the compressor and helps gas mileage
I am working with an AC mechanic who is doing this his whole life and is my neighbor
No issue with the R-12 being correct as it is stil used in commeecial refrigeration and readly available for that reason ( if licenced to purchase )
I do know it should be expensive to use now but getting a price on what i need from my friend soon
Like i said above - i do enjoy the exchange of info especially when i have a high regard for the persons cridencials ---as in you !


Glad you know your car is --Rust Fee --especially after crawling all over it for a while
A gift from the GODS ------I would say !!!
The only problem with that is now --You Can Justify -all those dollars you will be throwing at it with a --Clear conscience !!!
Gotta love the thoughts that go into bringing a car back to life or just keeping it up to date in any way possible
It is Called --Early 60's Cadillac Crazy and classified as one of the top 10 ---GOOD sicknesses-- one can have



That case of r-12 you are holding ( for youself --as i recall ) will be coming in handy at some time in the future --for sure !


Try this Google search link. Amazon seems to have an adjustable relay cheaper than rock auto.



Is that really the same --as the STV update kit ( $74 to $ 114 depending were you find it ) --for $8.12---REALLY ?

I called all the local auto parts stores for my list of A/c parts needed
They were --not even close - to being competetive with the internet prices finding a difference of 50 to 200 dollar on the same item in some cases
A bit of an education and these retail store just ---cannot exist for long --under these conditions ------unless they get with the program soon


To clarify on the stv update kit. The kit has a block off gasket set that renders the stv an empty shell after you remove the guts. The kit also has a non adjustable temperature relay. The relay senses the evaporator temp and shuts off compressor so that it doesn't freeze. Since its a non adjustable temp relay if you put the temp sensing bulb to close to a cold spot the compressor cycles off and on to much not cooling properly. If it's not sensing enough cold then the evap freezes. You end up moving the temp sensing bulb all over trying to find the sweet spot. By putting on an adjustable relay you can set it colder or hotter depending what works. 


High my friend !
Where you been -- miss you
The 20/80 % valve and the recirculation valve --are the same thing located on the fan housing under the hood on the passenger side
Two vacuum nipples on that valve
Old air products has that valve if you look at there parts on line for less than Ebays price

When i spoke to them on the phone they said they did not have the valve in stock but there it was on line for a better price

How is the Super upgraded high performance 429 64 Sedan coming along
I think you SB out and about this time of the year


The issue with the comfort control system is once you have it all apart - it does not pay - to not change all the older parts to make the system reliable and bullet proof
( you do not want to do this twice ) and that is where the expense comes in

1000 dollars in parts is better than 7500 to get the system up and running if you have the skills to get this project completed
A real lot of labor involved
The true reward is in the true comfort --the comfort control adds to the enjoyment of driving these great cars
The Ac system in my covertible is an option is so important to me that i would Never consider any Cadillac without this option
Some convertibles do not have the option while many do which would make this an add on option in 64 for the convertible


I very much appreciate your (and everyone else's) input and could not agree more on the value of AC. In the more than 100 old cars I've had over many years, only 5 did not have factory AC and almost all worked (cold on R-12 as I don't convert them), so we're on the same page in terms of enjoying it. And, yes, as long as I have it apart i am going to replace whatever I have access to. However I have a rule that has served me well and that is that I try to disrupt as little as possible of those parts that are already in place and working well because the potential for disruption and disfunction is greater-especially when dealing with a vacuum-based system. Maybe if I were a little younger and more vigorous I'd go for the whole thing, but in this case I'm just going to address the failed parts. Interestingly, this car's refrigeration system is good (no leaks and cold pipes) and the blower is good, it just does not blow out of any path and the temp wheel makes no difference. The cracked recirc valve is a no-brainer and a good place to start but it looks like the whole box with the blower has to come out in order to get to it. I've ordered the part and will be doing the repair as soon as I get it, then I will continue to go by Tim's book and troubleshoot the whole system. I also notice that on the power servo, the valve manifold seems to be sticking up on one end because I think a friction clip is missing on the peg that holds it in on one side. That surely can't be good for the system and I'm going to find a friction clip to push down on it to hold it over the rotary valve more evenly. 

This is actually my first Comfortron/Auto-temp repair as the other cars I currently have are cable-operated (for heat) Imperials with fewer  brain-directed (no rotary valve) vacuum solenoids, which makes them a little more straight forward to work on.  BUT, a big difference between GM and MOPAR is that if you put your hand under the dash where you can no longer see it in a MOPAR, chances are very high it will come out torn open by sharp, unfinished pieces of metal. Not so in a Caddy. 

I just spent a literal ton on money having my system restored to factory specs.

The shop says that the compressor is supposed to run all the time unless outside temp is below freezing.

If I decide to keep the car, I would be concerned about this.

I recall reading that these systems had a design defect or developed a component failure that would result in compressor failure.

Does this valve substitution fix this problem?



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