Volvo: 82 Volvo 245 A/C question, r12 freon, r134a freon

Question
I have an '82 245.  The air conditioning doesn't work, although when I turn the a/c knob, the engine "idle up" relay kicks in.  It has never been changed over to the newer freon.  I can't see anything through the window for viewing.

I perform most of my own mechanical work and am fairly accomplished backyard mechanic.

How hard is it for someone to change out the compressor, etc. for the newer freon along with what else will be needed?  I'm thinking it would be cheaper to replace the components and have a shop charge the system.  That is unless that that the charging is the easier part of the operation.

Any words of wisdom?

Thanks.

Answer
J.W.,
You should have a "York" compressor see if it runs and is fairly quite. If it works and all the hoses look good (check for oil spotting, sign of leakage) try charging the system. Diagnois and repair any problems.If I were you I would just stay with the R12 freon. The R134A freon runs at an increased pressure and that older style compressor does not handle that additional pressure so well. The idle up works well so that is a plus with the A/C on. If you want to make an improvement to that system add an electric fan in front of the condenser. If you need to replace the compressor it is not too bad doing that job. You must make sure the system is empty so seeing a service shop maybe in order to have any freon recovered. Charging the system is not to bad, however you will need some special tools, like a vacuum pump and a set of A/C manifold gagues and enough freon to charge the system.