I've been watching the AC saga on the list over the years and this is
one of the best, it may be the best that has come out.

Rob
becida@comcast.net

At  5/24/2011 08:12 AM, Jim Felder wrote:
>You need:
>
>two cans of R134, maybe three. They will not go in the car completely as
>will Freon, so you have to finish the job of emptying each can by sitting
>the can in a pan of hot water. I just use our cooking pans. This gets the
>last of the R134 out. The waterboxer has plenty of places for a pan so it is
>an easy one.
>
>You will need to change out the fitting where you fill the system. R12 cans
>and filling apparatus is not mechanically compatible with R134 fitting, so
>you have to convert. This is actually all there is to the "conversion."
>There used to be a lot of complicating factors like incompatibility of oils,
>etc but those problems have been solved by the development of new compatible
>lubricants in the freon that you are adding, so there is no reason to take
>the system apart. The "conversion" consists of buying the new fitting in a
>small kit and applying some locktite (included) and screwing the new filler
>port over the old one near the compressor on a 2.1. That's it (remember to
>get the little schraeder valve out first, it won't fit otherwise. You may
>need a very small pair of pliers or get one of the special valves for
>removing valve cores from tires from your FLAPS). There is a high-pressure
>side to deal with, but for professionals. I don't change that out. I do
>leave the kit in the car for the professional to install if needed, but in
>four or five years it hasn't been needed.
>
>You will need to get a filling hose. It is actually a hose with a pressure
>gauge on it and an adapter at each end for the R134 can and the
>newly-installed port described above. The hose goes between the two and and
>fills the system. The gauge usually has a face on it that you turn to match
>the ambient outdoor temperature, that sets the color coded areas to their
>respective places for accuracy. Basically, when the dial is in the green,
>you can quit filling.
>
>Apply the quick-connect coupling to the newly-installed fitting near the
>compressor. Then connect the can to the other end. You screw the can into
>its fitting all the way in, and then screw the big knob, which was formerly
>backed out, (you'll know all this when you see it) all the way in to
>puncture the top of the can. Then screw the big knob back out to let the
>R134 to flow. This is a good time to check and see if everything is tight
>and not leaking. Be sure to keep the can upright at all times. Don't let it
>lie on its side or turn over.
>
>Start the car and turn the AC all the way up. You will have to use the
>warming trick I mentioned earlier to get the last fourth or so out of each
>can. Two cans should do a Vanagon, but the main thing is to check and see if
>the needle ends up in the good zone.
>
>You're done. You spent thirty minutes and saved yourself a grand.
>
>There are cases on some cars where the system won't engage if there is no
>pressure in it, as in starting from scratch like this. In that case you have
>to jumper the pressure switch (google it's location if your system doesn't
>fill) to run the compressor until a certain amount of pressure gets in. I
>seem to remember that the Vanagon is one of those cars. So far I have done a
>98 GMC pickup, two 2.1 vanagons, a Jetta EcoDiesel and two Volvos. I also
>have a friend whose son is a certified automotive mechanic who told his dad
>that this wouldn't work on dad's truck. It did. All are working well. After
>I hit send, the list will no doubt warm a bit from the flames telling me and
>the reader that you have to take the system apart and you have to pull a
>vacuum before putting in the R134 and you have to use and understand a set
>of manifold gauges. I don't see the wisdom in any of that UNLESS you have a
>system that is so good mechanically that it doesn't leak down over the
>summer.
>
>Be advised that there are different additives already added to the R134 to
>help with certain problems. If you only get a couple of weeks out of a
>charge or if you know it is leaking in the first place, get a can of freon
>with stop leak. That works pretty well. If the leak is chronic, get a black
>light bulb and some leak check R134 that contains a material that will make
>the leaks show a bright yellow. Fix and refill.
>
>Yes, there are things you can do to get a little more cold out of a 134
>system, but I live in Alabama where it is hot and muggy as hell in the
>summers and nobody in my cars is complaining.
>
>Be cool (cheaply and easily),
>
>Jim