A/C conversion

[MY1978]

Okay, I have a 1978 C10 w/350 and it has the original A/C systems that you can not get (or afford) the freon for.  I have had several people say that you do not need to drop $1,500 - $2,000 for a new system to convert it.  There is apparently a less expensive work around that works great.  Anyone like to share that knowledge?   

[Shifty]

Flush (Dura141 flush solvent), the system completely, install new accumulator and orifice tube, add r134a conversion fittings, and green or blue o-rings at all the connections, and then run r134a.  Not as efficient as r12, but also around $7/can.

You should be able to get the job done for less than $100 in parts...(flush solvent being the most expensive thing)

[VileZambonie]

This is not a DIY job for someone who does not have the equipment. Yes, you can buy the fittings and such for a few bucks but call around and ask what they would charge for a retrofit. I would charge about $325 out the door for a retrofit on one of these trucks done 100% correctly if that helps for reference.

[Mike81K10]

Good point VZ! After the system retrofit is completed a vacuum has to be done and servicing with the correct amount of freon/oil etc. Many years ago I took up a training program on vehicle A/C repair and learned how to trouble shoot repair and even tear down compressors and rebuild them etc. Right now I would have a shop with the correct equipment and experience service my A/C to ensure it was right because it been so long ago since I messed with it and I don't have the equipment.

[JohnnyPopper]

Mike! We sound like we're from the same mold: Old Goofs 

[MY1978]

Thanks everyone.  Although my dad was a mechanic, in his days, at 80+, his mind not so clear now and I will not ask him to tackle this and consult with my local mechanic.

[JohnnyPopper]

The 1500-2000 is way off, run the other way!! 

[JohnnyPopper]

So when I first got my K10, it had a little gas pressure.

Bought the r134 adapters (these are metal fittings that convert your existing r12 fittings to current ones-under 10 dollars) and took it to a shop.

Took a chance on the accumulator and valve being good, they attached a vacuum pump, drew out the existing Freon, then recharged with r134 and oil.

Literally freezes me out. I think it cost me 150.00. 

[MY1978]

Thanks JP.  Once I am done with the cab restoration, bed liner spray, undercoating and exhaust I will definately get this done........unless I work it in the middle some where......

[wz7u]

As I remember things, I was told in the day that one could flush a system out but there would be enough residual R-12 left that it would set up a chemical reaction (sort of like how DexCool and green coolant don't play well together) and that all items had to be replaced with suitable parts. What I'm reading here is that what I was told all those years ago was nonsense.

To the posters that have done a retrofit of R-12 to R-134a with only a flush, how well is your system holding up? Has it ate itself from the inside out yet? Because, like any thinking person, I would love to get away with a recharge of new freon and not have to spend the $1500 -2000 I see these retrofit "kits" costing. Plus, I sure would like to see my old R-12 manifold gauge set be more than just wall art in the shop.

Like the meme says, I'm skeptical. Change my mind.

[Shifty]

Replace the accumulator.  It is a reservoir for oil, and doesn't always flush completely. Add to the fact that it'll take half a can to flush it, and the flush costs more than a new accumulator, it just don't pencil.  Change the orifice tube, it's a couple bucks, and has a screen filter of it's own.  Add the high and low pressure adapters (4Seasons/Murray/Everco are not the cheap aluminum ones that a lot of places offer), and that's it. 

Flush THOROUGHLY, until every component runs clean, lube up green o-rings, add 8oz of ester or PAG 150 oil in three places, compressor so that it doesn't start dry, accumulator, and the rest in the suction-side line, and then re-charge with your 134a.

[wz7u]

Thank you Shifty! Yours is the first good news I've had today and I appreciate that.

Sounds like a plan. I see in post two your prescription and it is doable. The manifold gauge set should flush as well, don't ya think?

Of course, I will do the parts change and flush, then I'm sure to hunt down any leaks that happen to be there, repair, and I'm off to the races (as it were).

Excellent!