AC CONVERSION TO R-134A (Page 1/1)
eti engineer NOV 29, 08:05 PM
I have a 1988 GT and wonder what it would take to convert the old R12 system to a 134A system. I was an AC contractor for 13 years in VA, but that was for residential and light commercial units which used R22 which is a whole different ballpark. I would imagine that I need to change out seals and possibly some hoses, but what about the compressor and other parts?
theogre NOV 29, 08:37 PM
Some highlights...
See my Cave, AC Conversion

If leaked out...
Likely need to have hose sets rebuild using current EPA rated hoses on top of whatever else. Engine hose set have been cooked for Decades and often leak.

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Dr. Ian Malcolm: Yeah, but your scientists were so preoccupied with whether or not they could, they didn't stop to think if they should.
(Jurassic Park)

The Ogre's Fiero Cave

Cajun NOV 29, 08:37 PM
Use the "Search" function, there you should find what is needed to make the conversion! Actur, it's quiet easy for specially for someone with your skillset.
Dennis LaGrua NOV 30, 10:35 AM
I've done a few R-12 to 134A conversions. If done correctly the system will blow very cold. The secret is to get all of the old 525 mineral oil out so you can get a full charge. I opened the system and blew it all out with compressed air . As for the hoses, the only ones that I can see that are under environmental stress are the ones in the engine compartment. Also replaced the orifice tube and accumulator and used the V7 variable displacement. compressor. Last conversion that I did was 7 years ago and the only hoses replaced were the compressor to bulk head units. I evacuated then recharged with Ester oil and R-134a to the recommended gauge readings for the ambient temperature. The system blows cold to this day.

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" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Hedman Exhaust, P-log Manifold, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, Champion Radiator, S10 Brake Booster, HP Tuners VCM Suite.
"THE COLUSSUS"
87GT - ALL OUT 3.4L Turbocharged engine, Garrett Hybrid Turbo, MSD ign., modified TH125H
" ON THE LOOSE WITHOUT THE JUICE "

[This message has been edited by Dennis LaGrua (edited 11-30-2020).]

Akheron NOV 30, 04:08 PM
I can tell you what I had to do, but keep in mind that my AC system was completely blown - bad compressor, blown tube assembly (long line under the car), bad switches, etc. etc.. Having said that, I replaced the evaporator and condenser (both from AC Global), drier, orifice tube, and compressor (all from NAPA in a kit), new pressure switches (SanTech - mounted on compressor), used ac tube assembly (Fiero Factory), new ac hose assembly, R-134a conversion kit (Fiero Store), and, this is important, a retrofit clutch cycling switch (mounted on the AC drier). This switch is needed due to the different operating pressures between R-134a and the old stuff. I had a AC shop rebuild the tube and hose assemblies with new barrier hose. Then, all parts were flushed, especially the ac tube and as hoses, to remove traces of mineral oil in the system. All o-rings were replaced with R-134a compatible o-rings, and the system was charged with PAG oil mainly because this was what the compressor was shipped with and recommended by the manufacturer. Keep in mind that R-134a will leak THROUGH the hoses over time at a greater rate than the old Freon, so the system will need to be maintained. It's been two years since I had the conversion done, and it's still blowing ice cold; however, I plan on have the AC system serviced this summer once the car is taken out of storage.

The hardest part of this whole process is trying to locate the proper parts. And if you begin this process, I highly recommend having ALL of the parts ready to install, otherwise, it gets delayed because most of the time the part you need is a week away.

There is also an excellent thread on the forum that provides a part list for every part you need including different compressor types. I can't seem to locate it at the moment though.

Hope this helps.