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Old 03-14-2017, 01:19 AM
jarretts70 jarretts70 is offline
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Default R12 or R134A - 78 Trans Am

I'm in the home stretch on my 78 T/A resto, the latest project is the A/C. I'm not an A/c expert by any stretch so I'm looking for advice on refrigerant.

I got the car in pieces about 7 years ago and have no idea how long it was apart before that. So the entire A/C system has been exposed to the atmosphere. I re-used the original evaporator, but replaced the condenser, accumulator and rebuilt the original A6 compressor (thank God for you tube videos). I also replaced the orifice tube. I just need new hoses. All O-rings have been replaced with modern green colored ones that can handle R134A.

Is there any reason not to re-charge the system with 134A? I've read that the system will run cooler with R12. The car is going to be a cruise night special, not a daily driver or anything. Plus I live in Edmonton, we only need a/c abut 10 days out of the year....

I never thought about it until I found out I need specific compressor oil depending if I go r12 or r134a. And even tho it will be a while before I take it in for a charge I want to get the compressor mounted this weekend & it's way easier to fill it with oil first.

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Old 03-14-2017, 11:38 AM
jerry455 jerry455 is offline
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I would use R134a. It will work fine. Just make sure you can draw down a good vacuum on it to get the moisture out of it. I converted my 1986 Grand Prix over and it worked great. If the accumulator is not new I would get a new one as they contain a desiccant in them to absorb moisture which can cause the A/C to freeze.

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Old 03-14-2017, 05:44 PM
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R12 unless you are switching condensers. Its not hard to find. 38-40 degree vent temps will be easy.

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Old 03-14-2017, 11:36 PM
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Isn't R12 illegal?

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Old 03-15-2017, 03:09 PM
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Not illegal to purchase or sell if you have taken the EPA 609 certification. It is easy and cheap. It is just another money grab by the government.

It just plain works better in systems that were originally designed for the stuff.

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Old 03-15-2017, 03:38 PM
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R134a readily available at a 1/3 of cost of the r12. Writing on the wall...can afford a new dryer and condenser.

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Old 03-15-2017, 04:18 PM
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Locate it on E-Bay or a large meet such as Carlisle. I have bought several of the 14oz cans for less than $20 a piece. I keep on adding to my stockpile whenever I can.

R134A isn't going to be around forever either. It is being phased out in favor of R1234yf.

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Old 03-15-2017, 05:21 PM
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More misinformation...r134a production isn't phased out. Not used in vehicle past 2020. Big difference. 6 bucks a can vs 20 bucks. Ok make the call...

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Old 03-15-2017, 10:54 PM
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I'll spend the difference for the right stuff for the way the system was designed.

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Old 03-17-2017, 03:01 PM
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Stay with R12...as 77 Canamman pointed out, there is no valid reason to switch.

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Old 03-17-2017, 03:58 PM
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Have converted several GM'S back to R12. Y'all can have the "cheaper" R134A n a 2nd Gen, especially one with t-tops.

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Old 03-17-2017, 04:21 PM
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R12 is the better refrigerant

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Old 03-17-2017, 04:21 PM
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R-12 gets my vote from experience.

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Old 05-10-2017, 11:03 PM
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I have 134A in my 72, and the first chance I get R12 is taking its place. I've had the cans just waiting for the right time. judge 273 you need re-read 77Canamman's post again. He said it is being phased out, not that it is.

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Old 05-11-2017, 12:26 AM
MUSLCAH MUSLCAH is offline
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Talked to my AC guy....to put R12 back in the 67 GTO.....225.00... ouch....but it's got to be done

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Old 05-11-2017, 07:31 AM
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Quote:
Originally Posted by azbirds View Post
I have 134A in my 72, and the first chance I get R12 is taking its place. I've had the cans just waiting for the right time. judge 273 you need re-read 77Canamman's post again. He said it is being phased out, not that it is.
I did and talked to a couple of guys who rebuild evaps. Both said 134A...

Reread my post...phased out use in appliances in 2020. Will still be widely available and the replacement works in 134A uses. We will see.

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Old 05-11-2017, 09:00 AM
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Quote:
Originally Posted by azbirds View Post
I have 134A in my 72, and the first chance I get R12 is taking its place. I've had the cans just waiting for the right time. judge 273 you need re-read 77Canamman's post again. He said it is being phased out, not that it is.
It's coming...

http://refrigeranthq.com/when-is-r-1...ng-phased-out/

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Old 05-11-2017, 09:01 AM
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Not debating which is better, This is what I do/did since I am not licensed to use R12 and it is pretty easy to do. I Just converted a car to 134 for a friend a few weeks ago. This was the cost of materials and this was using the original A6 compressor in a 78 Olds Cutlass.

R134:- $26. Walmart
Dryer: :$18 Ebay
PAG oil: $ 9. Advance
orifice Valve: $3. Advance
Conversion kit: $11. Advance
Solvent to clean system prior to pulling a vacuum: maybe $5. I buy it by the gallon and used about a quart.

Temps at the vent on 82 degree day was 46ish. Takes a few minutes to cool down the cabin because the fan just does not push a great amount of air compared to a new car but still made the car nice and cool.

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Old 05-11-2017, 09:04 AM
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Quote:
Originally Posted by MUSLCAH View Post
Talked to my AC guy....to put R12 back in the 67 GTO.....225.00... ouch....but it's got to be done
If you shop around, the 14OZ cans are easily purchased for $20 each. I just redid my 1977 Trans Am's system, which has a stated capacity of 3.75 lbs, or 60oz, which is just over 4 cans. I figure I have around $90 in refrigerant, but the end result is 36 degree vent temps, and a system that works as designed!

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Old 05-11-2017, 09:28 PM
MUSLCAH MUSLCAH is offline
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Last year with a 134 charge...in a 95 degree shop...the vents were 47 degrees at an idle...not bad for the 67 GTO

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