Hi.

I just installed a new compresser, lines, receiver/dryer and I think I am ready to charge. What I do not have is the FSM that tells me how many ounces of R134a to add. The system was R12 previously, but with all new compontents I was going to change it to 134a at (80%) of the R12 capacity. Anybody know what it calls for?

Truck is 86 22REC manual.

 

Not sure on how much goes in but I'd make sure i ran some dye through it

 

I recharged mine, old r12 that was converted to r134a before me, from what I read, it does need to be less going in but I think there is also a dependent on the outside temp. The gage I used had a 'V' notch and an arrow you point to the temp to know the range of pressure to get it at. I stopped at the lower end of the notch. It was just one of the bottle kits, black bottle with sealant in it.
The dude at autozone didn't really know anything about it. He thought, was certain, that all 1990 had r134a stock and didn't know anything about the differences.

 

Your high side pressure should be 2.2-2.5 times ambient temp and maybe a bit higher with high humidity. Low side usually ends up at 30-45 psi depending on temp and heat load. Vent temp with a converted system usually ends up somewhere around 45-55 degrees.