R12 isn't illegal. It is getting harder to get though the price has come down from the crazy days. You need a license to get it.

https://www.macsw.org/WEB/MACS/Section_6...dd-27fd9b9153f6

As for someone's definition of drop in, whatever. R12a requires no parts changes, no oil changes to run, though a new receiver drier is always a good idea. The EPA requirements and definition makes it clear that nothing is considered, by the EPA, to be a drop in substitute.


They say there are no such thing as a stupid question.
They say there is always the exception that proves the rule.
Don't be the exception.