Freon in High or Low pressure valve(fitting)?

[Brian R.]

Sounds like the valve is leaking. See if you can find a way to tighten it, like a tire valve stem. If not, bring it back and get one that doesn't leak. (of course, I may not have a clue as to what's wrong here)

[300+]

Sounds like a problem with the valve adaptor. It should not make the freon come out. They screw right on with no problem on the Toyotas I have done. Mine came from WalMart but really only one company makes these kits and they made these parts since the days of R-12.

Should be as simple as screwing it on running the AC on high pop the can on upside down on the low side and go to 25-45 pounds. Buy the cheap gauge its only about 15 dollars. The sight glass may or may not clear in a conversion. Less 134 is used than R-12 so don't overfill. Cans and kits usually have very good directions. I have been very pleased with the 134.
As a note. It is illegal to mix the freons due to reclamation issues, but they do mix fine from a technical point. Don't mix if you are ever going to bring it in for AC service. That would contaminate their refrigerant.