I can cruise in comfort now that my a/c is back together and working after at least 15 years of being torn apart. I thought that some of the steps might be valuable to others so here's what I had to do to get the system working again - First, reused all original components except filter/dryer. All hoses and compressor were off the car. Flushed hoses, evaporator, and condenser twice - once with mineral spirits, once with dedicated A/C system flush (Napa I think, smells like citrus) - did not flush muffler or compressor with solvent- Flushed compressor with double end capped PAG oil. Filled with about 8 oz DEC PAG in compressor and 2 oz in filter/dryer. Re-calibrated POA valve. Procedure for this can be found on Arizona Mobile Air sponsored forum - lots of good info there http://www.autoacforum.com/ Assembled system with new green o-rings and sealing goop. Installed a new filter/dryer - aftermarket from eBay. For test I pressurized the system to 102 psi with compressed air. Held pressure for 3 days, so I evacuated it to 25 inches of mercury using my Mityvac hand pump - it held this vacuum for most of a week, until we pulled it dow to charge. Evacuated the system with my friend's homebuilt compressor/vacuum pump (build from an old refrigerator compressor). Filled the system with 60 oz of R134a I had to fix some other stuff too - I somehow ended up with a long snout water pump, had to replace it with a short version to get my '68 accessory pullies to line up. The controls had problems - two switches behind the controls broken, thanks to board member California GS68 from Weymouth MA I have new(er) switches now! Thanks Ricky! Anyway, the system now blows nice cool air almost instantly after you turn the ac on. It's not ice cream headache cold like an old R12 system, but stays plenty cool so far in humid Michigan.
Hey John, Nice Job!:TU: You covered all the bases. I would only disagree with your source of final vacuum. A converted 'fridge compressor can't pull near enough vacuum to "properly" evacuate an AC system. Will it really make a difference in performance? Well, ...it can...and does...quite often. In your case, with a totally fresh, dry system, maybe not enough to worry about. o No: But it could be the difference between a converted system that works "good" and one that works "great". One thing that can boost your AC performance toward "Ice Cream Headache" cold is to replace the fan clutch. A Hayden Heavy Duty, or better, a Severe Duty unit can make all the difference in a converted system. Airflow over the condenser is the key to a successful R134a conversion.
Thanks for your comments. You are certainly right on the vacuum issue, and I think the system would last longer and work better if we'd used a "real" vacuum pump. Maybe next time. I do have a severe duty fan clutch on the car, it's probably about 5 years old.
John, thanks for that write up. The AC in my sportwagon has been down for at least 15 years. Everything is still there except the fan belt that runs the compressor. This gives me a place to start if and when I get to that project. Nicely done.
If you are not going to use R-12 as a refrigerant after you repair the system, you don't need to pull the system down to 30" Hg. If you use TC-134A, you can use the same process that used to be allowed in the old R-12 days, called a "sweep". First replace the receiver/dryer for one compatible with TC-134A. The receiver/dryer is where the moisture will be collected, so if you use a new one, then you can pressurize the system with TC-134A, and allow it to escape, for a couple of passes. This will eliminate the air. Any residual moisture will be absorbed by the desiccant in the receiver/dryer. TC-134A isn't as environmentally friendly as people think. It doesn't contribute to reduction of the ozone layer. It contributes to global warming instead. Since the global warming issue is considered LESS of an immediate threat than ozone depletion, TC-134A is allowed to replace R-12. Pick your poison.
I guess that you could do that procedure, but my only sources for R134a (chain stores) have it at $10-$15 per 12 oz can. I used 5 cans (60 oz) so I can't see spending $50-$150 to "sweep" the system one or three times. I'd say find somebody with a vacuum pump.
