How much vacuum leak before replacing a shaft seal

Hi everyone,

I am attempting to leak check an automotive rotary compressor with a micron gauge and vacuum pump with bungs before installing into the vehicle (used parts), testing each component one by one to pinpoint any leaks.

I understand most HVAC electric compressors are hermetically sealed and so can be drawn down to much lower levels, but how much vacuum should I expect a belt driven compressor to stabilise at with a healthy shaft seal?

After half an hour of vacuuming it got down to about 250 microns, closing the valve and stopping the vac pump it goes up to about 800 and when I checked it 24hrs later it seemed to have stabilised around 7000 microns.

What is acceptable here? I don't know how much compressors with these seals are used in the main HVAC sector, whether there is rules of thumb for this stuff?

I wanna get this right because I don't want to be polluting the environment with leaks, getting maybe 5 years without having to get it regassed, the auto AC machines seem a bit crap at finding leaks, and from what I've heard, the 30 minutes they usually vacuum for isn't always enough for evacuating moisture.

Thanks in advance!

submitted by /u/Iamnotanumber28
[link] [comments]