What is the maximum recommended pressure used for leak testing? I have a small leak around the shaft seal at test pressure of 175 PSI.

When I reduce pressure to 100 PSI I cannot pick-up the leak with electronic leak detector. Because crankshaft seal is on low side of system where pressures should not reach 175 PSI, should I be concerned?

I plan on using R-12 to re-charge to get back to factory performance. I will be changing compressor oil back to mineral oil as well. The 134-A conversion just doesn't do the job.