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Has any one done this on the older mustangs. I have a 67 fastback with factory air. I wwas wondering what would need to be done to convert to R134a and still keep it looking as original as possiable. http://f1.pg.photos.yahoo.com/bc/dougs289/vwp?.dir=/house&.src=ph&.dnm=Picture+949.jpg&.view=t&.done=http%3a//f1.pg.photos.yahoo.com/bc/dougs289/lst%3f%26.dir=/house%26.src=ph%26.view=t
 

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As I understand it, the r-134a doesn't mix too well with oil, so can starve the old compressors like you have on your stock setup. The result is a fried compressor.

To make a switch in refrigerants, there are a lot of hoops to jump through, and you really need to know what you're doing. If you have leaks in your system, I'd recommend fixing them and recharging with r-12. Just my $0.02 worth.
 

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I've read where to change the refridgerant, you MUST also replace the oil in the compressor. A kit built for this will contain new oil for this. You must also replace evey "O" ring on each hose connection, really no big deal.. I'm not sure about the outward appearance of any items as it relates to "Stock appearing". Consult the vendor on that.
R-12? It's really hard to find, they don't make it, and some of the substitutes are explosive.
 

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It's not necessary to convert to 134a. There are other products on the market that are compatible with R12. About 18 months ago I charged the system on my parents 88 Mustang using a product I think was called Mr. Freeze. You'll have to forgive me but I'm not 100% sure of the name as I use my remaining R12 for my fleet. If your interested get with me and I'll get you all the info. It was recommended by a friend who uses it at his business. I wanted something that was R12 compatible and was available to them on the west coast if they had a problem later. They haven't had any problems with their system, 225k miles and I heard this week they are driving it to the midwest! Not bad for an all original 88 Mustang with a 2.3/5spd. :)
 
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(snip)
I was wondering what would need to be done to convert to R134a and still keep it looking as original as possible.
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IIRC, the old-style York/Tecumseh compressors were used in a few truck applications after the R-134a change-over kicked in, so you might be able to find a compressor that "looks" original, while having upgraded seals, bearings, etc. to deal with the new refrigerant and the required oil.

Ask your question over on the www.aircondition.com message board; you'll get responses straight from the people who install and repair A/C systems every day.

I do know that to properly switch to the new refrigerant, you need more than updated o-rings. All the system hoses must be replaced with new ones which have a nylon barrier layer (not as expensive as it sounds), and the condensor and evaporator coils must be throughly flushed to get rid of the old refrigeration oil. I think the receiver/dryer must be R-134a compatible, too (different dessicant?), but that's got to be changed whenever you open the system to the atmosphere.

R-134a is only 80% as efficient as R-12, so the car will cool down a bit more slowly than before (Unless you buy a higher-efficiency condensor, which seems to help).

If you would prefer to stay with R-12, the aircondition.com website will lead you to an inexpensive online certification site, where you can obtain EPA certification to legally purchase "the good stuff". A certain online auction website which shall remain nameless usually has the 1-pound cans of R-12 available; buying the $$$ 30-lb. cylinder is not necessary.
 

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this is what i did to my 92 mustang, went to napa, got this kit that they sell. "legally" let the r12 out of my car. put on two nozzels, installed the r134 stuff. didnt replace anything at all, no o rings b/c you dont have too. its cold as can be and i love it COLD. put it on the lowest setting on max and away i go and it was 100 degrees outside. did it to 3 different cars also, all work great.
 

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I'm sure that you recovered the r-12 as required by federal law since it's a serious violation to release it to the atmosphere intentionally. Otherwise, you wouldn't be talking about it on a public forum?
 

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I converted my 1966 convertilbe with V8 and air conditioning to R134a in 1998. These systems use compression flare fittings at all the joints so there are no O rings to replace. Now in 1967 Ford installed the evaporator in an integrated heat/air assembly in the dash. You need to check and make sure all the blend air doors are working and sealing properly. This needs to be done irregardless of which refrigerant to use. The York compressor on these cars has adequate displacement to compensate for the lower heat capacity of R134a refrigerant versus R12. I would not use many of the other supposedly substitute refringerants on the market for R12. These are blends; have differenet vapor pressures and will leak at different rates. That means the proportion of the blends can change over time and a simple adding of a few ounces of refrigerant won't properly restore lost cooling capacity. I would strongly suggest changing the AC condenser to one that is a multi-flow model. It has more paths for the refrigerant to exchange heat with the air and helps compensate for the lower heat capacity of R134a. Some have had success with minimal work but the best and most foolproof installation is to remove and drain the mineral oil from the compressor, replace all hoses with new barrier lined hose and flush the evaporator. Use ester oil in the compressor. Do not use PAG oil. PAG oil will break down and have diminished lubricating capacity due to reaction with chlorine residue left behind by R12 refringerant. PAG oil should only be used in systems that have never had a chlorinated refrigerant such as R12 in them.
 
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