Ac refill questions

[yellowcat]

After much study and calling around I have more of an up to date ac understanding. I have a 1991 ford explorer with a five speed 4x4, 4.o liter 6 cylinder. It was never converted to 134a, which, from what I read is mostly good. Being that the 134a is not as cold as the old r 12. Among other problems 134a presents. But, it would have also been nice if someone would have spent the money, and properly fixed the ac.
I was simply going to put r-134a in, and hope for the best. Then, I heard about freeze 12, and autofrost 406a. I am leaning towards the autofrost because it sounds like the best deal, as far as compatablity, and performance. But I have not ruled out freeze 12.
I still have some questions. From the factory exactly how much freon(r-12) was put into my system? Second question is, how does that transfer to freeze 12 or 406a. But if I at least have the factory specs I can have a converstion done by the place where I order it.
I was told by someone that the system should be empty, then, just put in the required amount of refrigerant, otherwise, I would need to be a profeestional to get it right.

 

[cculter]

Most auto parts stores sell everything you need to do it yourself. Cans of freon, a good set of manifold guages to read the pressure and you are set.

 

[91exploreron37]

You can just put r134a into an r12 system. You will need a new reciever/drier with a dessicant bag compatible with r134a, flush the system and replace the oil with a r134a compatible oil such as PAG oil, also since the molecules of r134a are smaller than r-12 nylon lined hoses and new gaskets are needed to avoid the new refrigerant from seeping throught the pores(especially if the hoses are old and dry-rotted), and replace the fittings with quick disconnect-type r134a fittings and caps. And then you will need to have to system put under a vacuum to check for leaks and remove all the moisture from the system.

 

[marragtop]

When converting to 134a, you should also replace the orifice.

 

[91exploreron37]

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