R-12/R134a AC Retrofit - the truth??

I've got an '87 MJ without AC that's in great shape otherwise. I've got a '90 XJ Parts Rig (thanks to Lawn'Chero) loaded with options including AC, but since it doesn't run I don't know the true condition of it. I'm looking to swap one to the other, but don't know if it's worth the hassle. I've got FSMs so getting it all apart and back together shouldn't be too much of an issue and the years are close enough that wiring and such should be similar. I have guages and can get access to a vacuum pump.

I've heard (and read here, and on the 'net) so many conflicting stories of converting from one refrigerant to the other. I've heard that I'll need a new drier, o-rings, and refrigerant (total $100)at the very least. I've read that most likely a new compressor ($150) is in order since many fail shortly after the refrigerant change. I've also read that a converted R12/R134a yields 80% of what the original system could do. Since I live in hot and humid MO this will be marginal performance. To get some of that back I've read that a "parallel flow condensor" ($180) will be needed. So $450 seems to be the true conversion cost??

AAPAK quoted me a price of $720 for a complete bolt on R134a Kit with all new components. I'm tempted to go this route even though it's quite a bit of coin. I'm also not a candidate for OBA right now and when I am he York is sitting on the shelf waiting

So what's the smart money play on this??

Thanks,

- JP

I just did the 50$ autozone conversion and my AC is icy cold when its 90+ degrees outside, and humid as hell too/

Sorry to but in, but could you please explain the $50 Autozone way, as I'm also interrested. What's involved.

Thanks
Rob

Yea, I did the Schucks/Autozone whatever way too. It cost me $39.99 and worked great. I did it on my 90 Ford Country Squire. It is a kit that has 3 cans of R134a and 1 can of conversion oil. All you do is drain out the old, pump in the new(follow directions included). I did it a year ago and it still works great.
I figure that even if I have to redo it every 2 years it is still worth the money. So far no bad side effects. And believe me, I am one of the biggest skeptics of the "quick and easy", but this really works.
Even if it only lasted one year, it was worth the $39.99.

At the very least, when doing the quick, easy way, have a shop suck it out, then put it in a vacuum for about 30 min. This boils all the moisture out of the system.

I'd also recommend replacing the reciever/dryer. It's a desicant pack and absorbs moisture, plus it filters particles out. This would be done between the drain and vacuum. You want the system to be in a vacuum when you install the new refrigerant.

Steve

I added A/C to my MJ from an XJ.

I also converted to 134a

never had it vacuumed out or anything, just swapped all the parts in, filled with 134a and it gets so freakin cold that the little cubby hole under the glove box gets a coating of condensation on it when the A/C's running.

I just used it again for the first time this season, and it's still just as cold as it was last summer (which is pretty freakin cold!)

I did the swap on my 87. The old system had a hole in the high pressure line so I had to replace it. I did the Auto Zone method but I also replaced the dryer and expantion valve. It worked ok. The compressor gave out about 3 months later. I should also tell you that my rig had about 230,000 miles on it and I live in Fresno CA where the temprature rivals the surface of the sun. I put a new compressor and dryer on, recharged it and it works fairly well. I'm not overly impressed. Instead of vacuuming the system I "ran" a can of R134 through the system to "push" all of the air out. (I can clarify if you need) It's a trick that some of the old A/C guys used to use on the R12 systems. HTH

Neil

Wal-Mart sells the same kit for $35. I just found one on their clearance shelf for $25. Although it's recommended to change the drier (which will be easy for you to do, since you have to install a drier anyway), it isn't totally necessary and I know folks who have had good results just having the old R-12 evacuated and pumping in the R-134.

neil do you just run an extra can thrugh the system? I think i cracked the condeser and I am going to replace it if thats the case, but what else could I do ? run a 134a thrugh the system? please clarify

We use the inexpensive 134a conversion kits regularly in the shop, we never fill anything with R12 anymore. Like has been said, you want a thorough evacuation of the old regrigerant, and any moisture, but we don't have any trouble with the conversions.

93GRNXJ said:

neil do you just run an extra can thrugh the system? I think i cracked the condeser and I am going to replace it if thats the case, but what else could I do ? run a 134a thrugh the system? please clarify

Click to expand...

All you do is open the valve on the high pressure side and add the 134 to the low pressure side. This uses a whole can. Basically it just replaces the air in the lines with the R134. It’s not the preferred method but it’s better than just adding the R134 to a system that has air in it.

Neil

Well, I appreciate all the input. The consensus seems to be that the $50 kits work well enough.

My donor has about 200K on it, so unless the compressor look like it's been replaced I'll be putting on a new one and a drier at the minimum. I guess I'll swap everything else over and run it.

If it's anything like the heater in my MJ, maybe the AC will be the same. I swear you could bake a cake inside if you left the heat on high. I wonder if AMC used seperate AC Components on the MJ since it has a smaller interior volume?? If not, then I should be OK even with the reduced capacity of a converted system since there's less space to cool.

- JP

I was also told to replace the expansion valve as they may retain some of the old oil. The old oil is supposed to turn to a gel like consistency after it is mixed with the new oil. The old oil clogs the valve and makes it stop working.

Neil