dr bob

Not sure there are restrictions on importing it, but it's illegal to use it in any system in the US as a retrofit for R12. Take a look at http://www.epa.gov/Ozone/snap/refrigerants/hc-12a.html for the most current use limitations.

Rennlister Louis Ott had an interesting episode during a dyno session a few years ago at a Wichita OCIC. A belt came off and pulled a refrigerant hose. The oil and the flammable replacement refrigerant gas were ignited. Quick fire-extinguiser action by the group at the dyno session saved the car.

There are obviously other places in the world where hydrocarbon refrigerants are considered safe enough for automobile use. Hotter areas of SE Asia have it fitted as factory fill, due to cooling efficiency and material cost factors. Ozone depletion is not a factor although direct greenhouse effects may be. So far, US industries have successfully lobbied to keep propane and isobutane blends out of refrigeration systems in the US. After all, it would be way too cheap and way too effective compared with any patentable compound.

At some point though, we'll decide that we can make a safe hermetically-sealed absorbtion system that uses exhaust catalyst heat to flash ammonia, and then cool the cabin via a secondary liquid-to-air system filled with grape jelly or maybe propylene glycol.

dprantl

Your A/C hoses are probably very tired since they most likely are the originals from '81. With only front A/C, you have three hose sections in the engine bay. I would go ahead and have them rebuilt with barrier hose. I would just rebuild the two sections by the compressor and leave the third that connects between the condenser and expansion valve alone.

About hard lines, you must have them otherwise how would refrigerant get from the compressor/condenser to the evaporator that's housed in the dash? There is a high-side line going from the condenser to the expansion valve and also the low-side line going from the compressor to the expansion valve. These lines go down the passenger side of the engine bay hugging the engine side of the inner fender. They then go along the firewall and go through it right after the air box. The fuel cooler would be right behind/below the air box if you had one.

Dan
'91 928GT S/C 475hp/460lb.ft

The Forgotten On

I looked and you guys are right. There is one massive hard line running along the passenger's side sidewall. I definitely will not take that out. Just had the left over R12 evacuated because I was taking the lines off to get the rebuilt with barrier hoses and heard hissing. Had the system evacuated today and it had about 1/4 pound of R12 left in it. I hope you guys have working A/C. Mine doesn't work to save its life. It will be tons of fun to remove and rebuild everything. But at least it will work for the next 10 years.

curtisr

From RedTek's website:

Authorized Distributors in the United States:

Thermofluid Technologies, Inc.
P.O. Box 1114
Alcoa, TN 37701
Phone: Toll Free 1-888-676-9380
Local: (865) 983-1633
Fax: Toll Free 1-888-667-0695
Local: (865) 983-0068

Mel Brown Farm Supply LLC
http://www.melbrownfarmsupply.com/contact.html

You can also buy it at http://www.redtekstore.com/ as a kit, individual cans or boxes of the stuff.