Updating a/c for 134

[okiewelder1973]

I have a 85 c20 crew and am just looking for some help to update the system to accept 134.  Will the stock parts work or is there a list of aftermarket items i need.  111 in the shade here today!

[1979C20]

Youll need orifice tube, and either fittings for the accumulator or a new r134a accumulator, which is the silver cylinder on your heater box. Replace the compressor oil, as it could be contaminated with r12 and you cannot mix the 2. And flush the whole ac system

[Psycho71]

I know you didn't ask this, but since you already have an answer to your question I'll throw this out there too.

There is a drop in replacement for r-12, it's called "Freeze 12". I've used it in the past with good results. Had a buddy that dropped it in with some r-12 and it still worked just fine. No changing anything, just put it in and go.

Food for thought.

[okiewelder1973]

Thanks fellas.  I have a set of r12 guages...gonna check into the freeze 12

[jaredts]

I'm not sure why you have to replace any parts.  There is a conversion kit that includes r134a, conversion oil, and adapter fittings for under $40.  Ive done it on two vehicles and never had a problem (20 min.'s).  I think r134a and r12 "get along" together o.k. as long as you use the right oil and there's only traces of r12 left.  R13 was another story as I understand it.

[topp]

I'm not sure why you have to replace any parts.  There is a conversion kit that includes r134a, conversion oil, and adapter fittings for under $40.  Ive done it on two vehicles and never had a problem (20 min.'s).  I think r134a and r12 "get along" together o.k. as long as you use the right oil and there's only traces of r12 left.  R13 was another story as I understand it.

Whenever you open the system, and especially if it's original, the Accumulator should be changed as humidity makes it not work right, and it and the orifice tube collect junk.  The orifice tube is also different for 134.

134 and R12 do NOT get along together as they use entirely different oil (R12- Mineral Oil, 134 PAG oil).

Also when converting, the ENTIRE system should be flushed with A/C specific solvent to ensure no Mineral Oil remains in the system PRIOR to the 134 charge.

[frotosride]

134-a has been in the '87 for as long as i know and a vacuum pump and adapters like that kit jaredts spoke about will work great. The types of oil (R12- Mineral Oil, 134 PAG oil) doesn't effect the system but contamination will. r-12 is a chlorofluorocarbon and 134a is a hydrofluorocarbon..they don't mix well and if the system isn't completely evacuated (including oil) you can mess up your compressor, which isn't cheap. We've been using mineral oil in our 134-a converted compressors on the sub forever.