I've been thinking of doing an AC conversion on my truck. The current system is completely empty and probably has a leak somewhere (there was no pressure when I took it apart for the engine swap).

So I know to do the conversion you're supposed to convert to 134a you're supposed to replace most of the parts. I was wondering if I could shortcut on expenses and buy parts from a newer F150 or other 5.0 vehicle that came with 134a already. Assuming I luck out and find a compressor that isn't already seized. Then maybe I just need to buy new hoses and some o rings or something and fill it up.

Any suggestions? I figure if I'm looking at an interchange guide, it's going to assume I'm keeping with the R12 and not show compatible R134 parts (if they exist).

Thanks,

-Dan

 

You don't need to change anything unless something is broken. 134a will work fine in an R12 system.

 

So if I buy a can of 134a with stop leak in it, I can put that in my R12 system and it should work? Cause all that's wrong with mine is that its got a leak somewhere. Prolly a hole in the condenser, but I don't wanna spend the money on the pressure test.

 

It has to be converted to 134a, you can't just add it in to a R12 system that has R12 in it still. They're not compatible with each other but they're both compatible with the system.

 

So if my R12 system is bone dry, and all the R12 is gone... I could simply add 134a? Or is there no getting around changing parts? Just wondering, don't know much about a/c

 

My understanding is that the oils in the two systems are incompatible and will gel when mixed. You apparently have to use some kind of cleaner to remove the old oil from the system, particularly the compressor, before you can fill it with the R134a.

I'm not sure what kind of magic happens in one of those retrofit kits. Maybe there's an additive to prevent the gelling? Of course then I'd think you'd have to use that specific type of refrigerant forever.

 

Yes once you convert you don't want to switch back. You did say convert, and part of the conversion is blowing out the lines which blows out the oil. Change the orifice tube, add new oil, etc read the instructions on the kit. I never had a problem with residual oil.

 

+I have an 87 F150 XLT. The system was empty and a friend thats a Mech told me to go to the auto store and get a conversion kit. They are to convert an R12 system to R134a. It has a valve that screws on to the old low pressure side and one for the high pressure side. It comes with three cans of 134a with stop leak. When you attached the hose it tells you that freon will be released so if there is any in it there want be. Then attach the hoses as in the instruction sheet and fill it up. Mine has been working and blowing cold air all summer. The cost of the kit was about 50.00. If it works all summer here in the south and next year I may have to add more it is well worth it. its better than 4-500 dollars that most AC shops want to charge you.

 

^^^^ You didn't follow the instructions.