So search with my name. You will find tons and tons of R134 Retrofit information....

I am certified for R12 but I wouldn't spend the money for it. I have done hundreds of retros without any problems. I can get R134 to cool just as good, if not better then R12 in an R12 system!!! Just needs done properly. <img src="/forums/images/graemlins/smile.gif" alt="" />

You guys are talking me out of this. My 89 slowly lost all coldness, so am pretty sure it's a leak, but this all sounds like too much trouble and expense for a convertible. My 86 didn't even have AC and I never really cared, might just let this go.

Maybe I can gain some HP by disconnecting the ac? Is that belt connected to anything else important?

The step that is missing is using a vacuum pump to pull down the system completely emptying it of R-12, or air if that's what is in there. On these trucks, there is no problem with the hoses or seals when converting to R-134.

HECK no! Convert it to on-board air! Front Range Off Road has a kit.

Instead of re-charging I am gonna be re-moving and re-placing with a YORK to do the compressed air job. I already have it in there, but it is piggybacked off of the A/C compressor. Seen as though my A/C no longer works, it is mostly a trail rig, and the top is off 8 months out of the year...A/C is getting ripped out!

You are not going to see any significant gains in power with the AC gone, but maybe *a tiny bit*.

Kurt G.

Hey, post a pic of your piggy-back. Erik Beebs did one, I'd like to see yours. I seem to recall there is a mini-York that might fit nicely.

I'm licensed by IMACA for A/C and also ASE Master Certified. Not bragging but just want to make my point that I have been doing retrofits for 10 years now and I get the same A/C temps with R134 in an R12 system as if it had R12 still in there. There are little things that need taken care of to make this happen but it is cheap and easy.

My '90 Mazda 323 shop car blows 30* from the dash, my '84 Toyota truck used to blow 34* from the dash with a mechanical fan!! Now that it'll have an electric fan with the engine swap, I'm sure the temps will be even cooler.

The remarks about R134 not work as well in an R12 system are correct. However, there are ways to help it out. It doesn't.. without getting to engineer, carry the heat as well. (its enthalpy doesn't change as greatly with pressure as does R12) Running the higher pressures helps with this. I haven't tried this on the yota, but when the condenser went, my dad put a new condenser core from a newer model benz on his old 79 years back. When the evaporator core went, he again sought a larger one from a newer car. With some epoxy and plastic it was stuffed under the dash. The result was AC that functioned so close to original you couldn't tell.

Other things that help are finding ways to keep the air moving past the core when sitting still. Wiring up an electric fan for example is one way. If you have one, wire its realy in parallel with the temp sensor so it comes on with the AC compressor. That's probably getting deeper than most people to go but it's all about the heat transfer and moving more air through the core helps.

Frank