A few of us were looking for this info a while back. Seems legit.

http://www.autoacforum.com/messagevi...threadid=16311

 

On further inspection, this seems to be a different POA valve. My bad.

 

Nope, that's the right one, the valve just looks different without its outer case.

Here's the other thread that I've found with significant information on this subject.
There are other bits of information out there, but these two threads seems to have everything important in one place (okay, two places).

- Eric

 

But I'm not seeing a screw with a locknut. Just something that looks like a very small nut. I'll check out the other thread. Thanks Eric.

 

So you connect everything and it reads 28-32 for R12. Then turn the screw 1/4 turn CCW. That's it? No reading for the new pressure? Seems there ought to be a target pressure when set for 134A, not just 1/4 turn.

 

The screw and locknut are inside the valve, deep in the hole.

If you look at this picture, you can see he has a breaker bar and long extension sticking out of where the adjuster screw is:



(Incidentally, this picture shows how to check the valve without removing it from the car).

- Eric

 

This is what I see....

[IMG][/IMG]

And in the diagram I don't see anything that would be a screw. But it does look like if I turn that nut ccw it would release pressure on the bellows.

[IMG][/IMG]

 

Oh, deeper in there. Mmmkay.

 

Read the third post in the thread that I posted after yours:

R12 is 29psi, R134 is 26psi.

That's why I said that thread was the other useful one.

- Eric

 

Ahhhhhhh... Methinks you have one of the non-adjustable ones.

Apparently there are more non-adjustable valves on later cars, but it's really kinda random.

Maybe time for a junkyard run....

- Eric

 

I have to be honest, I don't have a setup for testing. I just want to get to the screw that turns 1/4 turn ccw

 

Hmm, that might be why the CSM says the valve is non-repairable and non-adjustable.

 

Chineseium gauge sets are cheap, and should be good enough for occasional use.

In your case, an old R12 set may be available very cheaply at a flea market or yard sale.

They're very good to have.


Cursed CSM!

- Eric

 

That valve is adjustable also. I would be more concerned about the rust you see down in there.

 

Just remembered the replacements were also adjustable but a pita because you cant calibrate it with the air and gauges attached like you can with the originals

 

You just turn the nut - that is what I did.
26psi is a good target for 134a.
One of these years I will get my AC system finished...

 

1/4 turn then?

 

I keep checking....

 

1/4 to 1/2 turn CCW for a guestimate.
It would be best if you could rig up a test set like in the picture.
More info on testing can be found here:
https://classicoldsmobile.com/forums...2-cutlass.html

 

Well we all know MAW. I'm introducing a new one; GEFN (good enough for now)
I'll start with a 1/4 turn. I'm guessing it would be better than nothing.