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R12 to R134

Mastiff

Mastiff

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I found some old threads on this, but nothing within the last 10 years or so. Anyone know of a true conversion kit to do this right? I'm willing to pay (within reason), but would like to do it myself. My understanding is that there are minimal adapter kits available, but that's not the same as having the system made to work right with the R134 in the first place. I'm pretty clueless about AC...

My system current functions but must have a leak since it stopped working after I had it charged last time - it took a few years to fully stop working. I'd like to get it working and make it so I can charge it myself in the future.
 
Mastiff said:
Found a great thread here:

http://www.gmsquarebody.com/threads/r12-to-r134-conversion.9684/

Lots of detail and sounds like the guy had great luck just evacuating the system, converting the ports and replacing some seals.
Click to expand...

This will work ok, but for much better results I would recommend a flush (to help get rid of old oil, etc), a Ford o-tube (made to meter r134a), a true parallel flow condenser (biggest recommendation from me, WAY better heat transfer that is needed with r134a), a fresh dryer (has a desiccant that may be spent and also a decent chunk of oil stored here) and the r134a switch that mounts to it (switches with pressures that is more effective for r134a), and all new o-rings (old ones wear faster with r134a). Do hoses if you can too (r134a particles are smaller and MAY leak through old r12 hoses). My hoses are original and I've had no issue. How old is the compressor? If its not too old it may be "compliant" with r134a. If its r12 only, it may soon leak. I've done this the easy way, and I ended up spending more than I needed to do it the right way the first time...now it blows COLD even in those AZ summers. Your results may vary.
 
Thanks for the help. Compressor is original, 1983.

The guy in the thread did some kind of flush to get out the old oil and replaced dryer, but not new condenser. I'd gladly do all the things you recommend, but not sure where to start as far as sourcing the right parts. That was kind of my original question, has anyone bundled this stuff up into a kit? A detailed shopping list would be just as good.
 
I know that someone will have something to say about this stuff, and why it shouldn't be used. But after looking around and having a buddy whom I like no other, I charged my '90 with Redtek R12A last week. I installed the Spectra parallel flow condenser, ( which doesn't bolt in exactly) , new compressor and accumulator, 3 cans of the R12A.
I did not pull a vacuum due to the website instructions.

I have been enjoying 20 to 25 degree vent temps with 90 to 95 degree temps outside. This morning it was 77* outside, and I got 19* on the thermometer. We don't have humidity here, really....

The system was running 134A for the last 6 years, and it worked fine with the original hoses and the orifice tube that NAPA recommends for it. As far as I can tell, all it had was conversion fittings combined with replacement parts before.

20170608_182849.jpg
 
If you buy stock replacement hoses/dryer/etc. everything has been built as R134 compatible for a long time. The exception would be real NOS stuff from 20 years ago. Also, many old hoses work fine with R134 anyway. I see no reason to replace the compressor if it works, doesn't leak and is quiet. The R-4 gets a bad rap, but it is one of the largest displacement ones available. When you're looking for good performance from a mediocre refrigerant, swapping to a smaller Sanden is couter-productive (even if it may have a longer life). So the things you can do to ensure good performance:
  • parallel flow condensor (but go big, many of the "stock replacements" are actually smaller than the original. The original is actually quite large)
  • smaller orifice tube (anything rated for R134) or the VoV.
  • Fans/shroud (the stock can work great with good clutch and good shroud, but big electrics cool a little better at idle)
If you're opening the system anyway, replace the O-rings wherever you do. Make sure you get a good vacuum for a long time before charging. Some A/C shops do this quick to save time, but the purpose of deep vacuum is to boil the water out of the system. There are some A/C technicians with no grasp of high school physics, but yes, water boils at room temperature when the pressure is low enough.

The stock pressure cycling switch is adjustable, so you can decrease the trip point a bit to improve performance with the new refrigerant.
 
Yeah, if you don't have leaks now, replacing hoses is not exactly mandatory, but replacing the dryer is, unless you're thinking of leaving it under vacuum for days on end.

I've seen A/C vacuum pumps for loan at Autozone, which is pretty interesting...
 
AC Delco 15-6960 is the condenser I used. It is about 3" shorter than stock, but it has worked very well, especially paired with windstar fans. I haven't heard of that Redtek r12a stuff but I'm curious.

Edit: I do remember that the condenser was ALMOST a perfect fit. I had to very slightly modify something but it was like a 5 minute fix.
 
nutt7 said:
AC Delco 15-6960 is the condenser I used. It is about 3" shorter than stock, but it has worked very well, especially paired with windstar fans. I haven't heard of that Redtek r12a stuff but I'm curious.

Edit: I do remember that the condenser was ALMOST a perfect fit. I had to very slightly modify something but it was like a 5 minute fix.
Click to expand...
I looked at that one after reading your older thread, but I got spooked from some of the reviews I found looking around.
I only had to use drill screws to relocate the lower (included) mounts, and then install the uppers to match.

Some will notice that the R12A is a hydrocarbon, which is supposed to be more flammable, but when ALL freon uses oil in the system, how much difference can there be???

I hope to report more in the future, my buddy has had problems getting a good compressor on one of the 2 trucks that he is using it in, but you know how parts store stuff is now... .
 
Is an orifice tube the same as an expansion tube?

They range in price from $0.60 to $45 on Rock Auto.
 
Lol, probably! If you can, go to a local parts store and have them pull one for your truck, then get like a 96 f150 orifice tube (it'll be blue) and make sure they're the same size. If not, pick another ford. That's what I did. They are like a dollar or two. That $45 one is probably one of those fancy VOV ones.
 
I have one of the VOV ones on my shelf, but I didn't want to try it after I found so many reporting having one quit working.
Supposedly it only takes a small particle of dirt to make it quit adjusting. Not sure though.
 
This AC Delco one is $2.75, listed under 83 K5 on Rock Auto and R135a compatible.

15-5151_Primary__ra_p.jpg
 
Orifice tube = expansion tube. Fords use TXV, but generally GM just uses the orifice. The tube is fine. I know I ran a VoV in mine for several years, but honestly can't remember for sure what's been in there for the last several. Even that should be like $12. If it's $45, it's not the right part - that could be a TXV (thermal expansion valve)?
 
They are asking 40-45 dollars for a vov. I just bought a regular 2 dollar one yrsterday
 
 
Also those o ring sets are not the greatest you might want to get a couple different bags/different brands.

Save old o-rings just in case.
 
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