Do I restore my AC or?

[saltdog]

It it were me, unless restoring to factory specs, I'd replace everything with a modern set up and pull a vacuum and be done with it. R134a just does not cool nearly as well as the original R12 Freon. R134a will not only leak from the 0-rings if not replaced, but can even leak through intact hose OE walls because R134a molecular structure is smaller than Freon.

 

[edgephoto]

It it were me, unless restoring to factory specs, I'd replace everything with a modern set up and pull a vacuum and be done with it. R134a just does not cool nearly as well as the original R12 Freon. R134a will not only leak from the 0-rings if not replaced, but can even leak through intact hose OE walls because R134a molecular structure is smaller than Freon.

That would be an expensive and time consuming proposition. I might consider this if I were building a daily driver but I am building an occasional use truck. My 1987 GMC is at the body shop and that A/C hasn't worked in a long time. The truck was not really used much for the last 20 years. Now that I am restoring it, I plan to get the A/C working again.

My plan is to replace the compressor. My original one is really no good, noisy. I will replace the condenser, evaporator and accumulator since I have them off the truck now. I will replace the hoses with barrier hoses, again since I have them off the truck. Then I will charge with R134a.

My personal experience is R134a does a good job replacing R12. I live in Connecticut and we do get some really hot and humid summers but nothing like FL, TX or AZ experiences, especially with the sun load in those states. The systems in these trucks is way oversized. A Suburban has the same displacement as a regular cab pickup despite the volume of the cabin and amount of glass.

I would also suggest adding some insulation. It will cut down on the heat load and make the cabin quieter.

 

[Battlac40]

gm says r12 to r134a you do 90% of the r12 fill, then subtract .25lb from the result

You would want to of course have all the r134a components possible like condensor and a new drier, and change orifice tube.
GM would have preferred a high pressure cut out switch installed, they did sell them

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15981985

but thats for use with a R4 compressor, id frankly disregard that specific use with the previous compressor type. A pusher fan that keeps airflow while idling would probably prevent the issue that they are designed to prevent

Is there a differance or what is the differance on process for an 81? -Thanks
great snip! @AuroraGirl

 

[AuroraGirl]

Is there a differance or what is the differance on process for an 81? -Thanks
great snip! @AuroraGirl

gm only initially retrofitted the instructions to 1988
After some years they made 1984 for some cars but they never officially went back further than 1988
but the AC in the trucks, to my knowledge, should be unchanged to the year they started using the R4. if you have an R4, i am pretty sure it would work for you.

but the previous compressor years, youd want to be mind ful of the system charge if it was different and any possible changes electrically. im not certain when r4 came around so thats about all I can say to that, otherwise it seems many guys do good just putting a crossflow in and changing seals/hoses and charging up with a compatible oil and a new dryer.

 

[Ricko1966]

I use 80 percent charge then sneak up on it,monitoring,duct temp and system pressures.