A/c compressor

On my '91 240 the cluch went out and is in need of replacement. It now runs on the old freon and am wanting to change over to the new stuff. Is the an easy operation if i follow the book.

When I tried to do this myself, I found out that the fittings for R-12 and R-134 are different, which makes sense so you don't try to fill your system with the wrong stuff. Just go to the local station and get them to top off your system. Usually AC systems have a check window where you can air bubbles if you need a charge. On a Volvo 240 the check window is on the evaporator part on the passenger side of the car next the radiator. Run your AC at full blast for 5 minutes or so and check for air bubbles. In the end I went to the service station and got my system topped off for about $70.