I did not know R 134 had a new style can tap. Newer truck sets in building most of the time now since not much need. AC didn't work. 11 years it always has, thought I would get gauges and maybe see if it needed a little. Picked up freon and now I see new can and self sealing valve top. I don't get out enough.

 

Yes it's always been that way. if you get good gauges they'll come with hoses to fit either one.

 

If you have one the old hoses to charge with r134a you can use it on the self sealing valve just have to pay attention to where it's open at.

I hooked the can to it and began turning the valve on the hose until it began to let freon out. Let say it was 3 turns.
Then I hooked up to truck and gave it 4 turns to allow it to fill. If you go too many turns it will block it off, or break the self sealing valve forcing you to release what you don't use into the atmosphere. (Illegal)

 

Found the correct valve for less than $8 so I just ordered it, everyone one needs more tools.

 

R 134a changed a few years back to self sealing cans. The can tap is different from the old puncture to use and self sealing. as far as having a guage set that does "both" it would need conversion hoses that connected to flare (r12) and acme (r134) they do exist. A new can tap might be worth the $20 to correctly dispense the freon.

 

I have dedicated hose sets for both but haven't needed either for years. I still have R12 cars and the newer is 134, just didn't know about the new can style.

 

New style self sealing can tap has a flat tip on the center piece. Old style is pointed to puncture the can. Old style will work on new style self sealing can but may not reseal if you don't use the whole can.

 

When I use a piercer I don't try to save partial cans.

BTW piercers are handy for many things like draining carb cleaner or other solvents out of spray cans that lost pressure and dumping spray paint when a can has a clogged valve. I'm too lasy to connect my airbrush to a spray can using a piercer (I collect piercers) but will eventually give that ago since spray can nozzles misbehave so often.