How I converted to 134A

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ghcoe
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Joined: Sun Nov 03, 2013 6:39 am
Location: SW Idaho

How I converted to 134A

Post by ghcoe » Fri Jun 26, 2020 1:53 pm

I have been keeping my A/C working in my '77 for a few years now. Here is my story.

First the system was stock. This was early 2000's when conversions were not well received. I converted the ports with screw on 134A adapters and replaced the receiver dryer with a unit that had a low pressure switch screwed into it. This was to keep the pump from being damaged if the system should go low on Freon. The result was better than no a/c but really was only good on the road. Cooling in stop and go conditions was not optimum.
This system eventually went out when the system over pressurized and blew out a hose.

Back to the drawing board. I found that there is a switch that not only shuts off the pump with low Freon, but also shuts the pump off if it senses high pressure in the system. You will want one of these. So replaced the receiver drier again and replaced blown hose. Results, still cooled on the road, but was nearly worthless in town. This system worked till I parked the Jeep in 2004.

Fast forward to 2013. Got the Jeep up and running again so it was time to get the a/c working again. Checked the system and it still had some pressure so recharged. This ran for a short time before the compressor locked up. Or so I thought the compressor was locked up. I found a 1989 Wagoneer with a Sanden A/C system still on it. Took the chance that the compressor was good and installed it. It did not work so I ordered a new Sanden and it did not work ether. I finally did some more reading and found that a possible issue was the system was clogged with the old refrigerant oil. So I went to Autozone and rented a flushing kit to flush out the system. Sure enough I got to the evaporator and it was clogged solid. I finally got it to clear by back flushing, and boy when it let go it LET GO! So come to find out I replaced two good pumps thinking they were locking up mechanically when they were hydro locking (if that is a word in the a/c world). Once flushed again the a/c was up and running. Cooling a bit better, but still not good enough in town. Hey it cooled for longer trips so I was good.

Next step was I lost Freon again on a trip. Turned out the fitting that went into the top of the condenser was rubbing on some metal. Over the years it finally wore through. Well thought I would just replace the hose. Not to be I damaged the condenser trying to get the fitting off. I forgot I needed a wrench on both sides of the fitting and twisted the condenser tube. It might have been still good, but instead of finding out the hard way I opted to order in a new universal unit. This meant that I was going to need to change out the hose fittings or get converters. I had to replace on already so I figured I would just have some hoses made up with compression fittings on one side and o-ring on the other. Found out they wanted $80.00 per hose so started reading again. Found out I can use regular clamps! So I ordered in some barbed o-ring fittings and some heavy duty clamps. I cut the old fittings off an installed the new fittings and condenser. Was nearly a bolt in for the new condenser. Charged the system and WOW! I had 38 degrees at the vent, doors open, at idle, with 93 degree ambient temperature. I couldn't be happier....

Well this is my story. It took me a long time to get to here. I hope it helps those out there to get here faster.

A quick breakdown to make it easier.
-First the condenser was the biggest change in cooling. I picked up a 24"x14" universal condenser for $35.00 on Amazon. It was nearly the same size as the one I removed from the Jeep. This was the major game changer to the system.
-They make compression to o-ring adapters so you don't have to change out your fittings/hose if you don't want to. My receiver drier has these converters installed. They work.
-Make sure you flush the system to avoid the old oil from clogging your system. Because it will! You can find YouTube videos on how to do this. It is simple...
-Install a low/high pressure switch in the system so you don't blow a hose or run you system low on Freon. It's simple to do just cut the compressor wire from the in dash unit where the switch is installed. Install two spade wire connectors and clip onto spade connectors on switch. Done!
-Hoses do not need to be replaced.
-Replace your receiver drier if you don't know if it has been compromised. Older receiver driers do not have ports for switches so it is a good time to replace the drier and install the switch, and flush the system at the same time. I picked up a drier with switch for $25.00 on ebay. They even threw in the compression to o-ring converters for free.
-Barbed o-ring fittings can be found. I used heavy duty hose clamps with my conversion.
-Pump down the system and charge. I rented the equipment from Autozone and watched YouTube videos on how to do it.
SW Idaho Overlanding Facebook: https://www.facebook.com/SWIdahoOverlan ... page_panel
SW Idaho Overlanding Youtube: https://www.youtube.com/channel/UCYuRx2 ... wVwZJ5oztg
1977 Jeep Cherokee WT
All-Terrain T/A® KO2
Safari Kit
Factory Brush Guard
Factory Tire Carrier
Custom Roof Rack

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Topic author
ghcoe
Posts: 1013
Joined: Sun Nov 03, 2013 6:39 am
Location: SW Idaho

Re: How I converted to 134A

Post by ghcoe » Sun Jul 05, 2020 9:31 pm

To help others I will list what I purchased to do the conversion.

Condenser used 14"x24" crossflow https://www.amazon.com/gp/product/B01CK ... UTF8&psc=1. It was very easy to convert the existing brackets to work. I think I had to cut of about 1/4" of the bracket and then used what I cut off as a guide to redrill the bolt holes. The bolt holes are spaced exactly the same as the one in my "77 Cherokee. The Condenser was the same size as the original condenser, but works much better because it is crossflow and has more cooling surface.

I ordered in these fittings Steel AC Barb Fitting Straight O-Ring Female Thread https://www.aliexpress.com/item/3282914 ... 4c4dnBtPpx and Stainless Fitting Barb Fitting Elbow 90 Degree Female O-Ring https://www.aliexpress.com/item/3283105 ... 4c4dnBtPpx with Assortment Kit Car A/C System Air Conditioning O Ring Seals https://www.aliexpress.com/item/3300928 ... hweb201603_
You will also need T-bolt clamps in the correct sizes https://www.aliexpress.com/item/4000295133389.html . You will need to measure for what you need or purchase a few different sizes that are close. This will allow you to cut off the existing compression fittings to the old condenser and let you install the new O-ring style fittings. You could also use these adapters https://www.walmart.com/ip/Factory-Air- ... =101002903 . Make sure to order the right sizes.
You can make up your own hoses with the above items by purchasing your own hose as well https://www.amazon.com/AGS-ACR053-Reduc ... 41&sr=8-30 . I was quoted $85.00 to build a hose locally. I found it more economical to build my own.

You will want to replace your receiver drier with one capable to accept a binary switch https://www.amazon.com/Vintage-Air-0732 ... 159&sr=8-1 . You will want the binary switch for 134A operation otherwise you will run the risk of blowing out a hose. The switch is easy to splice into the compressor wire. Again you will run into hose end differences on the receiver drier. On mine I have a o-ring drier, but have it converted with the compression fitting to o-ring fitting adapters. They were supplied by the vendor who sold me the drier. You could convert the hoses to o-ring fittings, use the adapters, or make your own hoses.

You will need a R-12 to R-134a Retrofit Parts kit https://www.walmart.com/ip/Certified-A- ... /656777458 . This converts the existing R 12 charge ports to 134A. It is simple to install.

At this point you will want to flush the system out. There are YouTube Videos walking you through this https://www.youtube.com/watch?v=Lnu8hA9F9S4 .

And then you will want to pump down the system and then charge https://www.youtube.com/watch?v=V31hmNA_Ogo . I watch a few videos so that you get a good feel on how to do it on both of these procedures. I actually just pulled down vacuum and then used a tool similar to this that I got at Walmart to install the Freon. It seemed a lot easier than fiddling with valves on the gage manifold.

As said in previous post the condenser swap was the game changer. All the rest was simple to do except maybe the flushing. By time I flushed the system though I had to pull out the evaporator from under the dash so I could get to it. It was completely clogged up with the old oil. Hose fittings where simply cut off old one clamp on new one and/or install compression to o-ring adapter or you can build your own hose if you order new hose. A bit of mods to the condenser brackets. Screw on the R12 to 134A adapters. Install the receiver dryer is a snap with the right parts. Cut compressor wire from under dash unit and install spade connectors to attach to the binary switch.

Well I know that some of these links will not work in the future so I tried to describe what I used too. Hope this helps, George.
SW Idaho Overlanding Facebook: https://www.facebook.com/SWIdahoOverlan ... page_panel
SW Idaho Overlanding Youtube: https://www.youtube.com/channel/UCYuRx2 ... wVwZJ5oztg
1977 Jeep Cherokee WT
All-Terrain T/A® KO2
Safari Kit
Factory Brush Guard
Factory Tire Carrier
Custom Roof Rack

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