Quick A/C question for the experts....


May 24, 2001
In the process of putting a vacuum pump on my system before I add freon. Question is, does the schrader valve on the high side port come out? Mine loosens up with the tool, but i cant get it out. Want to make sure if it can be removed before I force the issue. Thanks....
You don't loosen or remove. The hoses that attach will depress the Schrader valve to vacuum and charge. If you remove it you will loose the charge before you get the Schrader valve back in when you disconnect the hose.

Sent from my SM-G935V using Tapatalk
Ok thanks, evidently my gauges are for 134a, and my high side port is still r12, so I gonna need an adapter?
Are you filling with r-12 or 134?
I coverted to 134 and swapped out to the modern 134 fittings
The only time I connect to the high side port is for troubleshooting a broken system. I use just the low side port when charging.

Technically should be filling based on weight, right? I filled with my gauges monitoring pressure That is why I needed high side reading
Technically I should've only worried about weight of 134 going in .
Yes, fill by weight. Using the low & high side pressures is rather tricky as humidity and ambient temperature also play a role.

I always say, if R12 is still available to you, use it. R12 cools better, and runs at a lower PSI than 134. Lower pressure is easier on the older system and compressor seals. I'm not knocking 134 but 12 just works better in these older systems.
i replaced all the components on my TTA and was gonna fill it myself until i checked with a shop they charged 60 bux to vacuum check for leaks and fill i figured it was worth it, its cooler that i thought it would be pretty happy with conversion.
Look on the ac/heater box label. It shows how much freon to use. It is for R12. You can do a % correction. Most I've done, I use 90-95% of the fill listed, for 134.
You can buy a kit at Oreilly's for a permanent adaption to 134.
12oz cans..I think it takes 3+.