I am rehabbing my A/C system, which has been inoperative for five years. The last mechanic to work on it noted "A/C compressor leaks."

When I removed the compressor I found that the high-side o-ring was pinched; I suspect that this was the leak that the rocket scientist found and didn't fix.

Any suggestions for testing the compressor itself for leaks with it out of the car? How much pressure / how much vacuum should I apply to make sure things are working properly? I have a powerbleeder I can use to apply pressure and a mityvac I can use to draw a vacuum.

 

Look at this a/c replacement parts supplier's web site, they have technical service bulletins that discuss replacing seals and mention a 40/300 psi leak test with nitrogen or helium.

http://www.sunairusa.com/downloads.htm

But, if you use new seals, prep sealing areas, lubricate and install them correctly, you probably don't need this test. Maybe your local a/c shop can reseal and pressure test for you at minumum cost.