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post #1 of (permalink) Old 08-23-2002, 03:58 PM
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Incomplete R134A conversion - What to do?

I bought my Bronco about a month ago and I'm just getting around to doing work on it. I discovered that the previous owner(s) put a R134A compressor on what appears to be a stock A/C system. What will happen is that the A/C blows cool for about 15-20 minutes and then starts warming up. I guess that there's probably a lot of head pressuring building up.

My question is:
Should I put an R12 compressor back on and cough up the money for the high dollar R12 charging or complete the conversion? Has anyone tried using an R12 substitute like R406-A( or even found a shop that handles substitutes?

If I went ahead with the conversion what are the minimum components that need to be replaced? I guess I would rather go this way but I've heard quite a few complaints about the performance of conversions.
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post #2 of (permalink) Old 08-23-2002, 04:12 PM
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Re: Incomplete R134A conversion - What to do?

Here is what you need and how to do it. I did mine about a year ago it it runs great I live in Florida and it keeps my truck pretty cool with no tinted windows. I got all my parts at Discount Auto, you need to get a new dryer/accumaltor, orifice tube, all new o-rings, a cleaner for the system, some 134a a/c oil 2-3 ounces at most, about 4 or 5 can of 134a and one can of 134a oil charge. I found it eaiser to remove all of the a/c componets flush them with the cleaner, clean the fittings with some real fine steelwool. I took the compressor out and set it upside down for a day or so, so it could drain fully then I flushed it with the cleaner. I reassembled everything being sure to put a little a/c oil on all of the o-rings. After everything was back together I put a vaccum pump(got this from a rental store I had my own gauges if you don't check with the rental store be sure you tell them its for 134a) on the system to check for leaks then I let it stay on for about 4 hours to get all the moisture out of the system. After this you need to start the truck turn on the a/c and add 2 cans of 134a(don't worry about the knocking it will knock until you add the oil charge) after you add the 2 cans add the can of oil charge then top off the system by checking your gauges check with a local a/c shop for the right pressures on the day you do this because current temp has a lot to do with the pressures. Be sur you tell whoever you get the parts from that you are upgraded to 134a so you get the right parts. I left out so step by step directions to make this as brief as possible if you have any question feel free to ask. This was not that hard of a job and it saved me about 1,000.00 doing it myself. One place that I found leaks all the time is the tube that connects to the condensor it looks like the condensor is all one piece but, it is not there is about a 4 inch piece of tube that connects to the condensor with an o-ring I have had 4 Ford trucks that all have leaked here I guess nobody ever replaces this o-ring cause it is kinda hidden. Hope this helps and Good Luck,
post #3 of (permalink) Old 08-23-2002, 05:49 PM
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Re: Incomplete R134A conversion - What to do?

Any compressor will work fine, and the stock system (with a different orifice tube) will work fine with R-134a - you're just low on refrigerant. Wal-Mart sells a hose that connects to the low side fitting to add some for less than $15, and they sell R-134a and oil charge also.

Pressure building up isn't why it's not working; it needs pressure to work. What's happening is that the small amount of refrigerant is getting compressed and then the clutch starts cycling because there isn't enough low-side pressure.
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post #4 of (permalink) Old 08-23-2002, 06:33 PM
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Re: Incomplete R134A conversion - What to do?

Get a set of gauges and see what your pressures are reading.I agree with steve,your suction pressure is probably low.If the clutch cycles on and off pretty quick that's a good sign.Still I would find a friend who can loan you some gauges or rent some.It will come with a charging attachment.

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post #5 of (permalink) Old 08-23-2002, 09:59 PM
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Re: Incomplete R134A conversion - What to do?

Thanks guys....I'm off to fish in Montana for a week so I'll fix it up when I get back and report back on the results.

Thanks again!
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