1992 Cadillac Deville A/C vacuum

SEAN03

MEMBER
1992 CADILLAC DEVILLE
4.9L
V8
FWD
AUTOMATIC
142,000 MILES

Hi I am going to probably replace my A/C seals this weekend. Their is no refrigerant in the system as of now. I assume it leaked out the car sat for awhile without being run so I think the seals shrunk. I have a 1992 Cadillac Deville. It had R12 in it. I have a half of a 30lb bottle of R12 right now. So once I replace the seals and schrader valve I am going to pull a vacuum and see if it holds if not I will fill the system with nitrogen and find the leak that way. Now for my question this system only has a low side port with a schrader valve in it. The high side does not have a schrader valve in it and it almost looks like a quick connect coupling. Can I pull a vacuum only using the low side of my manifold gauges or do I also have to do the high side also. If so how would I pull a vacuum on the high side. Thanks.

3 Replies

HMAC300

MECHANIC
48,601 POSTS

Yes you can pull a vacuum with low side this may have been half assed converted to r134 if that I why you see the high side the way it is it should have a Schrader valve

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Friday, May 23rd, 2014 AT 4:08 PM

SEAN03

MEMBER
523 POSTS

You know I don't notice it until tonight but the high side port does have threads on the outside. When I try to put my manifold gauges on it the my hose is to big for it. It just swallows it. I have never seen anything like it. Their is no schrader valve in it though. Their is like a small black round thing that sits at the bottom of the port and is pushed sideways instead of laying flat. When I take the cap of on the high side cap off you can hear something leaking. But I know the system is completely empty. Maybe it is oil or something. I replaced the low side schrader valve and nothing came out so it is weird. I know these are R12 ports because we have owned this car since day one. I know cadillac changed the compressor out the first year we had it. It was a defective compressor. Is their a way to somehow change the high side port out and make it an r12 port. Or can I convert the port to R134A and just use the couplings I have for it and still use r12 refrigerant. Thanks. It looks like the high side port just screws out.