A/C System Refill R12 or convert to ???

[Celica91STX]

Am trying to figure out what to do about Freon in my 91 STX Celica??
Can't find R12 locally or easily; so looking at refit to r134a, of Freeze12, or one of the other sort-of-134 products .... What is the best/most economical and least complicated for this generation Celica?? Do you need to change out te drier and expansion valve, how much oil and what type is needed (this is the 1.6 4 cylinder engine) and do you need to have this done in a A/C shop?
Thanks in advance for your help

[PittsburghCeli]

I converted mine to r134a just by screwing on the schrader valve adapters to the high and low side. They come in a kit along with a can of a/c oil and 2 cans or r134a from autozone for like $30, but I wish I would have got the more expensive kit that comes with the gauge so you know exactly how much to put in so you don't overfill it, because you can ruin it it you put too much in. They also have cans of r134a with stop leak at autozone.

Just make sure you follow the directions. Basically you start the car and turn the a/c on high, connect the hose to the can of r134a and then connect the other side of the hose to the low side on the car. Then puncture the can by twisting the knob on the hose connected to the can and then untwist the knob to release the r134a and tilt the can which should get cold. Fill it to 3/4th full depending on the capacity of the a/c system (check the manual). I only put the 1 can of oil and 1 can of r134a in just so I didn't overfill it. It has been working fine for a couple of summers but I could use another can and that is why I wish I bought the gauge because you just never know how much is in there.

You can also buy the r12 off the internet fairly cheap.

An a/c shop will do a better job because they can release and flush out any old r12 correctly on the high pressure side and fill it to the correct level.