I'm trying to nail down a fairly fast leak on my Cleansweep compressor.  It leak at a rate of about 8 PSI/minute when filled to 125 psi.  I've isolated it as far back as I can while still having a gauge to watch and have no visible leaks anywhere with soapy water.  The compressor is 5-6 years old I think (I've replaced it a few times because it quit!).  What are the chances its leaking back through the compressor where I can't see it?  I have a new Viair 350 to put on but its a pain in the rear!