I have an under dash unit for a 1963 Ford Galaxie. It is a dealer installed unit that was pulled from a parts car a few years back. I was curious as to how many cans of freon 12 it should take to charge the system. I understand that it varies somewhat, but I'm looking for a good round about number. Thanks
Probably about 2lbs? Maybe a little less. I just charge them until the pressures are right and it's cold...
Two cans to fill it up the first time, and however many to refill after you find the leaks. Have fun!
Unless you have a stash or a friend that does, you won't find any R12. R134a may not be compatible with older units.
There seems to be lots of R12 around, although everyone wants a lot of money for it. I think that's because everyone thought it would all be gone, so they set the price to where no one would ever buy it. Strange. I got rid of my stash, I bought it in the early 90s and I still had half a dozen cans a few years ago. I decided I don't really need old AC on old cars any more. And 134a seems to work in older units, just like magic. Who'd a thunk it?
Thanks. I picked up three cans of r12 at a junk sale for $5. I was curious if that would be enough to get started. I thought about filling it with 134a first and finding leaks. If it wasn't cold I was gonna replace it with the r12.
As far as leaks, I hope you can find a shop, friend or another hobbyist that has a set of gauges and a vacuum pump. Connect the gauges and vacuum the system. It should hold. A part of the reason it was phased out is old systems having leaks and just getting topped up, not fixed properly. If it doesn't hold vacuum you have the choice of diagnosing and fixing with R12 seals and filling with Freon, or going ahead and doing the upgrade to R134. This will involve seals, a different oil and most likely the receiver/drier. There are a bunch of resources for doing the conversion, so do some research. Which way you go depends on cost and availability of the stuff and if originality is of upmost importance. You do not want to use R134 to check for leaks. It's not compatible with the seals and oil. https://thegrumpymechanic.com/what-happens-if-you-put-r134a-in-a-r12-system/
A 1963 R12 system would have a sight glass. You charge until the sight glass clears, then add just a bit more until high side pressure begins to climb.
I'll be facing the same issues sometime this coming summer. and, thinking of adapting residential AC technology to find the leaks before using any of my R12 stash. Use an inert gas (most techs use nitrogen) to pressurize the system first. Some have used MIG bottles to do it with mini-split installs. Not running, just bottle/regulated pressure.and see it it holds. Could even plug some lines and use higher/lower pressures in parts of the system. Once that's done, vacuum it down and add that precious R12, or do an R134 conversion
Don't bother with the inert gas approach... Are you saying that it worked before, and now it's out of refrigerant? If so, then you have a leak. If you don't have a leak detector, or otherwise don't know where the leak is, you should fix it first. For about 40 to 50 bucks you can get a low end electronic leak detector off Amazon, throw enough R12 in it to get to about 50 psi, and seek out the leak. (Some guys use soap bubbles first, which CAN work for you, but I've found that it's a pain to do.) Fix the leak. EVACUATE. Purge the system. Evacuate again. Purge again. Evacuate again. Charge the system with one can of R-12. On the second can, watch the sightglass if you have one. If you don't, hold your hand on the liquid line leaving the condenser as you charge the system and watch your High side pressure. When it starts to slow down increasing pressure, you will note at some point that the liquid line begins to cool slightly. When the liquid line is "warm", but not "hot", then you have reached the point that you are feeling "subcooling", that is, the lower few rows of the condenser is delivering a good column of liquid to the thermal expansion device. If you have a sight glass, do as mentioned above, when it runs clear, add a tad more and feel the liquid line at the same time. When it starts to cool, you are DONE ! Good luck.
Dont use R12 to find a leak, there’s a reason they stopped making it. The system in my car is an original Mark iv with a York compressor. When I had a new condenser they converted it to use R134A it only involved a new drier, new oil, new fill fittings and ensuring the system was free from R12, maybe worth thinking about.
Another problem is finding a set of R12 gauges and a can tap that still work...the rubber seals on mine went bad, and they seem to be different from 134 service equipment. If you can suck it down to 30 inches, and it holds for a day after you close the valve and turn off the vacuum pump, it'll probably work ok for a while. But yeah, having millions of people dumping R12 into the atmosphere was a problem. Now that only a few people do it, I think the serious danger is past us.
This will tap R12 or 134 and also the small cans of dye and stop leak with the included adapter. It punctures the side of the can, so no messing with the valve on the can.
If the system has been apart you do have to pull a vacuum on it before filling it. The shop I worked in last in Texas had a compressor out of an old fridge or freezer for a vacuum pump. The thing was mounted on a cheap little hand truck that was probably older than it was and they had put the correct fitting on the suction side to connect to the gauges. My gauge set will connect to R 12 systems but I bought the adapters for R 134 for it and now the screwball who runs this state has outlawed the sale of R 134 and we have to use what ever they call for or bootleg it in from out of state. My gauges aren't all that old though probably 12 years.
The best way to charge, in a pieced together system, is by using pressure gauges. Both low and high. That's after you vacuum the system, and it's not leaking. Vacuum does two things: remove any residual moisture, and removes non-refrigerant gas like nitrogen and oxygen. Look up the Pressure-Temperature curve for R-12, and at your temperature. High pressure is approx 2-2.5x ambient (degrees F) for R-12; i.e. at 80F the high pressure is around 160-200 psi. Low pressure around 15-20 psi. Those numbers will get you in the ballpark, and you can tweak the charge for lowest vent temp. Remember to use max on air, and use a fan in front of radiator to ensure adequate airflow. Just as a comment, R-12 is less sensitive to charge amount, especially if a little overcharged. R-134a is much more critical on charge amount for best performance. R-134a uses POE ("ester oil") or PAG (factory fill oil), whereas R-12 uses mineral oil. The R-134a will not dissolve mineral oil, that is why you need to flush the old R-12 systems to remove mineral oil before you replace with ester oil and convert to R-134a refrigerant. If you leave the mineral oil, and just add ester oil. you have mineral oil in your system doing nothing but decreasing efficiency.
If you do switch over to R134a Do not overservice- unlike R12, R134a will lockup your compressor if overcharged
https://en.wikipedia.org/wiki/Thomas_Midgley_Jr. Scroll down to Legacy. Not how I'd like to be remembered. No legit shop will have or use R12. So if you can't DIY, your only real choice is a substitute. Seems there was a kit, but it's not in stock now. I'd check the big companies for this if yours is going to require a bunch of stuff. https://www.macsautoparts.com/1963-...t-fit-air-conditioning-system-60-83980-1.html
R12 can be legally used and a lot of old commercial coolers(food cases/pop boxes etc) use it and are regularly serviced by repair guys. One should not use it in a known or suspected leaky system though. That's why I recommended a high pressure. leak test with inert gas earlier. Making sure that no leaks are present. Systems can hold a vacuum test and still leak under operating pressures, after all it is less than 14.7PSI differential if a perfect vacuum. All that said, I would prefer to switch to 134 if assembling a new/used parts system.
We used this method often when designing new mobile HVAC systems. Issue is system needs to be under full heat load. Meaning maximum expected ambient and “maximum” expected compressor speed (assume Hwy cruising speed”) for passenger vehicle. If you can’t mimic this, then chances are the system will be under charged. Tested lots of systems we built, where discharge pressure started to rise rapidly once you surpass the “critical charge”. To do A/C “properly” you really need the requisite tools, and knowledge. Sure, people “wing” it all the time with varying degrees of success. We don’t have any info from the OP on much of anything, so can’t really add too much. Older vehicles typically took more refrigerant than modern vehicles due to the design of the heat exchangers (copper tube/alum fin) than today’s designs. Also, longer hoses due to the size of the car/engine compartment. If I were to guess, I would start with 2 lbs and go from there, as others have stated, once system is buttoned back up and can hold a vaccum of no less than 29” Hg for at least an hour. Might take a while to achieve this if system was left exposed to atmosphere for any length of time (i.e. longer than 1 hr). This is because of any moisture that had been absorbed into the system will need to be boiled off during the vacuuming/evacuation process. Fresh compressor oil, new o-rings, new filter drier/receiver drier are mandatory. Chances are the expansion valve (TXV) is stuck, so might need a new one of those. If it were me, I’d be throwing in a new/rebuilt compressor as well.
Fill and pressure test with nitrogen. Then when you think you’ve fixed all the leaks, vac it down and use the real refrigerant.
Hello, We had a 327 powered 40 Ford Sedan Delivery. It came with an old York compressor. The cold air was a good unit for the times and was very cold inside the back cave, too. It worked well in the warm So Cal arena. But, eventually, began to lose its “cold” power. So, refilling took a couple of freon cans. That lasted the whole Summer, but as fall began, the hoses were old and needed replacing as leaks kill the whole process. (Remember, we bought it as a finished car, but, it turned out to be a "project car.") At this time period of hot rod building, the old York vertical compressor units were the mainstays of A/C for custom installations. No rotary units as yet and no Vintage Air Company. When the rotary units came out, the York units were old hand and not the first choice of custom installations. But, leaks do happen. Usually a couple of cans would charge it enough to get the cold back inside. Like burning oil, it was as an ongoing process and a repair from an A/C repair shop took place. Jnaki That was our first A/C unit and it worked so well that driving the sedan delivery for my wife was number 1 and she always had first choice. Either that or a funky 62 Corvair… that made the choice simple. Currently, all of our daily drivers have A/C and with the new tech, almost problem free. If a repair is necessary, the dealer or A/C repair shop has all of the tools and “stuff” to get it right. New hoses, parts, etc. Yes, a hot rod guy should know what goes on the motor or in the motor compartment, But, sometimes, it is easier to just let some other professional take care of the problem. Despite having an old York compressor, the 1940 Ford Sedan Delivery 327 powered with A/C was a pure gift for the both of us. We eventually had to replace some seals in the vertical unit, new hoses and a leaky fitting. But, those early A/C units were usually from GM junkers in scrapyards, so, who knows how it was taken care of in the build or from original owner(s) I usually got stuck driving the Corvair… what a choice in comparisons… But, a happy wife… and that direction, lasts forever. YRMV DEC 23 MON JUST SOME RANDOM
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