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Firebirdjones · 07-12-2012, 10:26 AM

I converted all my AC cars to 134 many years back (79 pickup, 88 Iroc, 72 chevelle, most recently my 72 blazer) and I've done a few for customers when the need arrises.

The easier ones by far are the newer R12 vehicles such as my 79 pickup.

I prefer to remove all components and flush, remove the compressor and drain. The evap I leave in the car and flush as well as the condensor. I like to make sure all old oil is removed and make sure there isn't any trash floating around. I simply use non chlorinated brake clean that evaporates and leaves no residue and then compressed air.

After that's done I like to replace all the 0-rings (it's all apart anyway). I reassemble with a new dryer (and orifice tube if equipped). I also like to poor a little pag oil in the evap and the compressor before assembly. Install the proper quick disconnect fittings,,,then suck it down for about 45 minutes. If it holds a vacuum I'm ready to charge.

Toss in the recommended pag oil and then 134 using gauges to watch high side pressure.

I don't bother to change any lines, and still use the old A6 style compressors as long as everything looks to be in good shape and functioning. If it's questionable I'll replace it.

My 79 pickup has been done this way for the last 10-12 years without a hiccup and blows ice cold in the AZ heat. Never had an issue with any of them. Most of your complaints of 134 not working as well comes from trying to use it with the old style R12 condensors that aren't as efficient and can't cool the 134 freon well enough. It can be easily changed if desired for a little more money.

It's very straight forward and simple, just take your time. I do agree that 134 has since gotten more expensive and it's starting to make the change over questionable. R12 is relatively easy to obtain and not much more money.
A recent trip over to a friend that runs a local AC shop I found that he has R12 freon, tons of it!! It's not much more money to just have him throw it in an older car, and actually cheaper than doing a 134 conversion.

07-12-2012, 10:26 AM	#20
Firebirdjones Registered User Join Date: Oct 2009 Location: Prescott, Arizona Posts: 2,396	Re: R12 to r134 ac conversion. COST?? I converted all my AC cars to 134 many years back (79 pickup, 88 Iroc, 72 chevelle, most recently my 72 blazer) and I've done a few for customers when the need arrises. The easier ones by far are the newer R12 vehicles such as my 79 pickup. I prefer to remove all components and flush, remove the compressor and drain. The evap I leave in the car and flush as well as the condensor. I like to make sure all old oil is removed and make sure there isn't any trash floating around. I simply use non chlorinated brake clean that evaporates and leaves no residue and then compressed air. After that's done I like to replace all the 0-rings (it's all apart anyway). I reassemble with a new dryer (and orifice tube if equipped). I also like to poor a little pag oil in the evap and the compressor before assembly. Install the proper quick disconnect fittings,,,then suck it down for about 45 minutes. If it holds a vacuum I'm ready to charge. Toss in the recommended pag oil and then 134 using gauges to watch high side pressure. I don't bother to change any lines, and still use the old A6 style compressors as long as everything looks to be in good shape and functioning. If it's questionable I'll replace it. My 79 pickup has been done this way for the last 10-12 years without a hiccup and blows ice cold in the AZ heat. Never had an issue with any of them. Most of your complaints of 134 not working as well comes from trying to use it with the old style R12 condensors that aren't as efficient and can't cool the 134 freon well enough. It can be easily changed if desired for a little more money. It's very straight forward and simple, just take your time. I do agree that 134 has since gotten more expensive and it's starting to make the change over questionable. R12 is relatively easy to obtain and not much more money. A recent trip over to a friend that runs a local AC shop I found that he has R12 freon, tons of it!! It's not much more money to just have him throw it in an older car, and actually cheaper than doing a 134 conversion.