How to pressure-bleed the brakes on a B-van?

You gave me an idea, redfish. For my purposes I could just tie the Mity-Vac directly into the lines and pressurize them. I don't actually need to pressurize the master. Thanks a lot!

The rear brakes are in good condition and adjusted. The problem is that I'm not getting any pressure to the rear to speak of. It's gotta be either a bad master cylinder, bad or blocked proportioning valve, blocked lines or bad body-to-differential hose in the rear. I would like to diagnose it properly rather than firing the parts cannon.