R134A Conversion

[kenm78]

I am about to get a 80 Chevy Big10 pickup. Has factory R12 a/c blows really cold. Don't plan on messing with it until something happens. But when it does how hard is it to convert it from R12 to 134A? What parts have to be replaced? What can be kept? Any helpful info will better prepare me for a change like this. Thanks a million everyone ahead of time.

[Restrorob]

Here's a post I made some time back;


When converting from R-12 to R-134, To acquire peak performance from the system ALWAYS replace the receiver dryer and drain the oil from the compressor. This removes all the R-12 contaminated oil from the components. Draining the compressor fully may require removal from the vehicle. There is a A/C flush solvent that should be blown through the lines, evaporator and condenser to remove any oil or other contaminants from the system. This can be done using a type of siphon air hose blower.

Re-fill the compressor with X ounces (depending on system size) with A/C R-134 mineral oil, Add a couple onces to the new dryer as well. Replace the orifice tube while the system is open and install all new O-rings where lines were removed.

Now,

With all components re-installed and system closed, Gauges and a vacuum pump can be installed. I let the pump vacuum 20/30 mins, It should pull 20" of vacuum if there are no leaks. Now turn the pump off and let the system sit 20/30 mins, If the gauge stays at 19/20" there are no apparent leaks. If vacuum raises, All removed fittings will need to be re-checked for tightness or cut O-rings.

If the system checks fine at 19/20" the R-134 is ready to be installed.

Approximate price to convert from R-12 to R-134, If you have the tools and equipment little over a 100 bux.

[kenm78]

Thanks a million... Exactly what I was wanting to hear!!!

[DragRag]

I'm in the biz so to speak, and atrue vacumm is 29.9 inches HG. A 20" vac can leave contaminents in the system. I always leave it on so it jerks down far. if i can only hit 20" I always start looking for a leak some where. One other thing, most people don't know about it, but you can run R409a and many other R12 drop in's in your system. other are hot shot, mp39, cold shot etc. There are many to choose from, and act like R12. I find that 134A systems plug cap tubes more then the older gases do. I personally use R409A myself. one draw back is you need an EPA card to buy it.

[kenm78]

So ASE certification won't will not cut it to buy that type of freon?

[DragRag]

Maybe, not sure. I don't have an ASE, I have an EPA cert. The cert is what the parts houses ask for, you could try...