I am getting ready to pull the engine on a 67 BB with factory air and I still need to purge the AC system. How do I do this.
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Re: Purging AC system ?
Jerry,
You will need a vacuum pump to evacuate the system. Connect it to either of the charging ports and let it run. If you have a new drier and it is not very humid 30 minutes or so should be fine. If there is any question about the moistue, let it run for 24 hours. It won't hurt anything.
The reason that you evacuate the system is to pull 100% the moisture out of it. If there is any moisture in the system, it will freeze in your expansion valve and block it so that you won't get any cooling.
If you live around So. California you can borrow my pump. Or, Harbor Freight used to sell a cheap A/C vacuum pump for about $20. I don't know how well it worked, but it is probably worth a shot. Or, take it to an A/C shop and have them evacuate it for you. It cannot cost very much.
What refridgerant are you going to use? There are some new ones seem to be much better than the R134 and R12. Freeze 12 is one of them. It is 100% compatible with R12, has similar performance characteristics, costs about $8.00 per can, and is not a CFC. If you are filling a new system I would HIGHLY recommend that you NOT use R12 or R134. Go with one of the new non-CFC refridgerants. Even the new R134 is probably going away soon.
good luck,
Dave Christensen -
Well...
I'm not familiar with the '67, but if there are valves located at the pump, you could simply close them, disconnect the pump (with minimal loss of refrigerant), and tie back the hoses. If not, the only "legal, environmentally friendly" way is to have a licensed facility evacuate the R-12 from the system.Comment
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Re: Purging AC system ?
Dave,
I need to replace the refrigerant in my system. Where can I purchase thw Freeze 12 product? Anyplace where there is more information about it? I have tried to stay away from the exotic substitutes for R12 but, this sounds like something worth switching to.Comment
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Re: Well...
I need to disassemble the whole system because there is damage to the evaporater box. I plan to have a compressor rebuilt and have other elements pressure checked.I am not sure how much damage has been done. The system was not cooling when I got the car.I have been told to block all openings to protect the system. I am not sure if there is even gas in the system. The car cannot be removed from my garage.I need to do it myself or have someone come to my house.Do I need to purge the system since I'm removing all the components?I am starting a restoration and it will be several months before the system will be reassembled.From reading the posts I will probably use the company in Tampa Florida to help me get the system going when I'm ready.Comment
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Re: Purging AC system ?
In some states, Texas is one, the parts stores such as Pep Boys and Napa sell it. I am in California and they look at me like I am from outer space when I asked about it here.
I bought it from Sherco-auto.com http://www.sherco-auto.com/fr4012.htm
You can get more information about it on the Freeze12 website.
There are quite a few of these products now - Duracool 12A, FR12, Glacier Gold, etc.
No, I don't have anything thing to do with any of these companies. I found out about it when installing an A/C system on my XKE.
Dave ChristensenComment
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Re: Well...
Jerry,
In you first post, I thought you were ready to fill the system and needed to evacuate it to remove the moisture.
To purge it legally, you need to be a licensed refridgeration specialist and use the recovery equipment so that the Freon does not escape into the atmosphere and destroy the ozone.
In the old days, before the Freon Police, you would just open a fitting and the Freon would escape. The oil will come out with the Freon as they are completely miscible in each other.
A wise person would not be smoking, especially when doing this operation. The burning Freon creates phosgene (mustard) gas. Passing the Freon gas through a lit cigarette is enough to make smoking even more hazardous to your health.
good luck
Dave ChristensenComment
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Thanks, Dave. That was helpful! *NM*
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If the charge has leaked already...
then your problems are over. Just cap off the disconnected components to keep out moisture, bugs, etc. When repairs are complete, you will need normal evacuation and charge. BTW, exposure to air for even a fairly short time will destroy the drier function of the filter drier, and it must be replaced.Comment
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Re: Purging AC system ?
Dave
There is another product which I have used on my '69 and on other modern cars using R-12. It is produced by Enviro Safe Refrigerants, Inc of Pekin Il. I have ordered it over the internet. They also make all of the accesories needed such as the correct oil, die charges, fittings etc. It works even better than R-12- less is needed, it is environmentally safe (n CFC's) and actually blows colder air. It can be added to existng R-12 charges or substituted.
Hope this helps.
Jeff SalzComment
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Re: If the charge has leaked already...
Dave, I have never replaced a filter-drier before so I have never seen a fresh one up close. How do they preserve the drier media while they are on the shelf waiting sale? Are there foil seals on the connections that have to be removed before installation?Comment
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Re: Purging AC system ?
John,
Before going with anything other than R12 or R134a, check out this web page to see what you are getting.
Freeze12 is a blend made up of 80% 134a (and 20% 142b). Since it is 80% 134a why not just go with 134a? Much simpler and easier.
tom...
EPAComment
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Re: If the charge has leaked already...
The ones I have bought just have plastic caps on the fittings. I did not think they were "sealed" though.Comment
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Correct....
plastic plugs to prevent atmosphere for entering and no special 'seals'. The active ingredient in receiver dryer isn't rocket science, fellas. It's simply silica (remember the old salt shaker lids that absorbed moisture, changed color and you baked the moisture out in the oven?).
The original receiver dryers were meant to be serviced. The sight glass was removable. You could pop it off, dump the contents, replace with off-the-shelf fresh silica (in sealed packets available through GM service), and completely rebuild the jar. In fact, that's what those offering 'restored original' receiver dryers do using scrap yard donors.
Heck, you can do yours yourself at home! Take it off, fill with isopropyl alchol, swish, and dump. Repeat as necessary until the effulent comes out clear & clean. Now, plug the holes and mask the sight glass. Media blast the exterior and lay down a fresh coat of paint. Pop the sight glass and lay in fresh rubber refigerant gaskets for the next 25-years. When all is done, put the finished receiver dryer in your kitchen oven on 'keep warm' setting overnight to force absorbed moisture out of the silica pellets inside and PLUG the inlet/outlet holes when you take 'er out of the oven to cool. You're done!Comment
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Well, Gee...
I wish I had known that before I bought a brand new NOS receiver drier. Maybe I can redo my original and sell it on ebay. :-)
Jack, would you bother "regenerating" (that's the ChemE's term for heating a dessicant drier to drive out absorbed moisture) a new receiver drier before installation? I guess the plastic plugs prevent ambient air from circulating through the drier, but it seems like after 30 years of setting on the shelf, it would absorb some moisture from the air without positive seals. Suppose GM still sells the silica and the gaskets? What does the isopropyl alcohol do, wash out the old refrigerant oil?Comment
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