R134 AC Conversion kit - New '73 Vert Owner

7173Mustangs.com

Help Support 7173Mustangs.com:

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

Animal Lawyer

Well-known member
Joined
Sep 3, 2020
Messages
279
Reaction score
37
Does anyone make an R-134 conversion kit for the 73 factory ac? Mine is currently inop (belt removed) so I will need to test the entire system, and probably recharge, seems like the conversion to 134 will be necessary no matter what. 

 
There is not really a kit. You get the green o-rings from your local parts store in an assortment. There are O-rings at every fitting connection. The expansion valve at the fire wall will have two o-rings on the firewall side and two on the hose side. You need to clean the seats for the O-rings, wire brush, steel wool, and put a little mineral oil or new compressor oil on the rings as you go back. I also put some anti seize on the threads on the fittings to prevent them from sticking next time. You will need to use a wrench to hold the expansion valve as you loosen the connections. 
You should pull the heater box AC box and install a new heater core. Do an air pressure check on the new core before you install it at 15 lbs. of air. I have had a couple bad out of box. You might want to have the evaporator flushed and the condenser also.
The compressor has two plugs one in the top and one in the bottom both have O-rings, fill / drain. There is also a vent valve in the rear of compressor has O-ring. 
The hoses have O-rings at the compressor. If your fill valves are original on a 73 you will not have the isolation valves like 71 - 72. There are shrade valves in the fill ports get new ones and install, like in your tire fill valve. You need to buy the R134 adapters any parts house has them.
Now the hoses to to the filter dryer and you need to get a new one. O-rings there also. O-rings where the filter dryer hooks up to the condenser. 
When you tighten any of the fittings you need to tighten and loosen and tighten several times to seat them. After together you pull vacuum on the system and let it set for an hour or so to see if you have a leak. If it leaks then you have to loosen and tighten all the fittings again. When you fill put a bottle of the UV dye so you can find leaks with black light in future.

I use Duracool myself out of Canada. It is a highly refined propane product and is way more efficient than R-12 or R134. There is no danger of an explosion. Propane cannot burn in a closed system has to have oxygen to burn. There are millions of vehicles on the road today that run on propane or CNG, compressed natural gas. They do not blow up and have 20 gallons not just 8 or 10 ounces of propane like the AC will have. 

Here is link to the Duracool site. http://www.duracool.com/Duracool/refrigerants.html

I have two cars with it in them no issues been in 4 years in one. 

If you do not have the Ford manuals you need to get or download to understand the system and how it works. I cannot tell it all here you need your reference in hand. I just got gauges and vacuum pump from harbor freight for less than one visit to an AC shop.

It is not a black science but leaks can run you crazy. Can cost you hundreds at AC shop also.

 
I've converted a few and never had any problems. You'll read that a larger condenser is needed with R134, but I just used what was already on them and never had any cooling problems in 105° Northern Nevada summer weather.

 
Thank you. I just ordered the shop manuals, depending on the state of the hoses I may just replace them along with the dryer & expansion valve. Would I have the condenser and evaporator boiled out (radiator shop?) or is there a better way to clean them?  I am hoping the compressor isn't toast (belt was removed 2 p.o's ago).

 
I'd pull a vacuum on the system now to see if it holds. There may be a leak in the system somewhere. If there is, it is better to know now. Chuck

 
I'd plan on a compressor rebuild.  If it isn't good, it will fill the rest of the system with trash and everything will need to be cleaned and or replaced.

It is probably more effective to put in a modern system if you aren't restoring the car.

 
Back
Top