AC Compressor check valve/relief valve

[Kesp4.0]

I've removed and tossed all of the old R-12 equipment from my 93 and purchased all of the new R-134a components. The one thing I kept was the relief valve from the old compressor. I've got the new line that connects to the new compressor and it appears to have a new valve in it on one side but the other side looks to have an opening in it as well, I'm assuming for another valve (maybe one valve for low pressure line and another for high?) Will the valve I removed from my old compressor work in this capacity of should go just buy another valve, or does something else go there? The relief valve I'm planning on reusing is about 3\4-1" long, cylindrical

 

[JustinGibson]

I've removed and tossed all of the old R-12 equipment from my 93 and purchased all of the new R-134a components. The one thing I kept was the relief valve from the old compressor. I've got the new line that connects to the new compressor and it appears to have a new valve in it on one side but the other side looks to have an opening in it as well, I'm assuming for another valve (maybe one valve for low pressure line and another for high?) Will the valve I removed from my old compressor work in this capacity of should go just buy another valve, or does something else go there? The relief valve I'm planning on reusing is about 3\4-1" long, cylindrical

Do you have a picture? I recently did mine and didn't run into this issue

 

[Kesp4.0]

Thanks for the reply. Here is a pic. As you can see there is the compressor and then the line that connects to the back of the compressor (not connected). You can see one side (high side?) has a small brass check valve on the rear of where it connects to the compressor, and I am holding a small screwdriver pointing at the hole beside that brass valve. What goes there? I just checked the valve I removed from the old R-12 compressor and the little valve I have won’t even fit in the hole. I keep thinking it’s for another relief valve, perhaps for the low side?

 

[JustinGibson]

View attachment 326427
Thanks for the reply. Here is a pic. As you can see there is the compressor and then the line that connects to the back of the compressor (not connected). You can see one side (high side?) has a small brass check valve on the rear of where it connects to the compressor, and I am holding a small screwdriver pointing at the hole beside that brass valve. What goes there? I just checked the valve I removed from the old R-12 compressor and the little valve I have won’t even fit in the hole. I keep thinking it’s for another relief valve, perhaps for the low side?

Sorry for the late response, there is a brass nut similar to the other one on the block that is missing. I attached a picture of mine to use as reference. I recently redid my system using all UAC parts I had some issues with the first compressor but the quality of the lines aren't bad and they're on rockauto pretty cheap.

 

[Kesp4.0]

Thanks for the picture that shows the missing piece. This tube is actually a UAC tube from Rockauto, so that's just perfect that the piece is missing, lol. Is it a relief valve or just a brass nut? That's the low side, correct? Thanks again

 

[JustinGibson]

Thanks for the picture that shows the missing piece. This tube is actually a UAC tube from Rockauto, so that's just perfect that the piece is missing, lol. Is it a relief valve or just a brass nut? That's the low side, correct? Thanks again

I believe it is a relief valve. It is not a traditional but like the other one on the block. Yes that is the low side. It should be running to the dryer.

 

[Kesp4.0]

Thanks so much. Yeesh, this is a difficult part to find as an individual piece. I’m not sure if there’s a special lower pressure high pressure valve that goes there or if they just stuck a similar high pressure valve as used on the high side. I imagine that since low side pressures are only around 40psi or so compared to the high side perhaps the valve should pop off at a much lower psi. I might just go back to the pick a parts and find a 94 or newer and just grab a few. I appreciate the pic and the info. It’s a good starting point for me to find this thing

 

[JustinGibson]

Thanks so much. Yeesh, this is a difficult part to find as an individual piece. I’m not sure if there’s a special lower pressure high pressure valve that goes there or if they just stuck a similar high pressure valve as used on the high side. I imagine that since low side pressures are only around 40psi or so compared to the high side perhaps the valve should pop off at a much lower psi. I might just go back to the pick a parts and find a 94 or newer and just grab a few. I appreciate the pic and the info. It’s a good starting point for me to find this thing

Yeah I don't know anything about it but I would probably contact rockauto and maybe they can ship a new one to you if you have time to wait for it.

 

[Kesp4.0]

I’ve got the time for sure but I think I’m screwed with them. Looking at the picture it doesn’t show the piece as included, and in looking at their available parts for this AC line I’m seeing only the hi side relief valve which- even if I wanted it- looks to be of the older design and of a smaller diameter than what this opening is for. I think I’m going to check local parts yards for a 94. Fun times! Thanks again for your help

 

[JustinGibson]

I just looked and you are right that the photo doesn't have one but the other two brands have the valve and my UAC line came with one and I just did mine this summer. Is it threaded?

 

[Kesp4.0]

Yes it's threaded. It's a larger size, probably 10mm or so. I believe it's the same size hole as what is on the high side. I think I may have found the correct part on line, but I'm still probably going to stop by the junkyard juuuust to see what I can grab