I have a 1974 F250 Ranger XLT with dealer a/c. Is there a R-134a kit with a compressor, lines, and orings that uses Vee belts for around $500?

-Thanks, Keegan Hall

 

It's more than lines and seals, you will also need to replace the condenser and dryer. I think you have a thermal expansion valve as well, so you will need a TXV. None of these are hideously expensive. If you carefully flush the system with alcohol and replace the O-rings all around with R134 rings, you may not need new lines at all. If you are going to go with R134, you are obviously not going full original - why not change to a Sanden compressor?
There is much less parasitic drag on the engine if you do. A new Sanden-style compressor made overseas (meaning probably China, but what isn't now) will cost less than $200 at most. You will need a mounting bracket (they cost about $50 - look for York to Sanden bracket and you should find one easily). Depending on the fittings on your old compressor where your hoses mounted, you may need adapters for the hose ends - mine were about $13 each. There are numerous threads on this conversion, and at least in my case (I have the 300 cid six) the difference in drag is tremendous - the old York compressor slowed the engine down a lot, but with the Sanden compressor I literally almost can't feel the drag when the AC is on. Look into it - you would come in well under that $500 budget. The down side is that you have to source the parts yourself, but for a little legwork on your part, you free the engine from that big compressor's drag.

 

Thanks for the reminder on the Sanden compressor. I think my York "let the blue smoke out" so I'll be looking to replace it. Also, I've seen the conversion kits on eBay in the past.

 

It's said the R134 does not cool a well as R12, given that the system is designed for 12 - I tinted my windows to help the system out and find that while the system isn't spectacular, it makes the truck survivable in Houston summers, so it is not that shabby, either. The 134 is so much cheaper that it was kind of a no-brainer to do the system and compressor conversion. I was lucky and the only leaks I had were cured with a new hose (or could have also had something to do with the condenser and dryer - who knows if the old ones leaked?)

 

R134 has smaller molecules and therefore has a greater tendency to leak. Also, R134 needs a higher operating pressure, again contributing to leaks.

I had my A/C converted to R401 - it has the same pressure curve as R12, and seems to work well. R401 was designed by DuPont to be a direct replacement for R12.

That being said, I think the Sanden compressor is probably a good conversion.