On my '91 GL I have been working to get my AC going and have had
minimal success. However, I did have OK, not great, success with
R-134 last summer. I did not change anything in the system other than
the condenser resistor which had burned out. Unfortunately, there was
a small leak in the system so I had to start over this year. Story is
too long to tell here.

I think that with the fairly low cost of R-134 you could get the
system going for the balance of the summer by emptying it and putting
in new refrigerant. As I understand it, the trick is to put in the
RIGHT amount or R-134 after being sure you have all the old stuff
out. You also need to be sure you have the correct amount and type of
lubricant in the system.

It seems it is impossible to determine the amount of R-134 in the
system unless you fill an empty system and have a pretty good scale
to determine the amount going in to the nearest 2-3 oz.

I am working to convert my system to R-406 (Autofrost) which should
work better than R-134 at a somewhat higher cost.

Herb