Bleeding brakes...

Not a Mopar, my 02 Cheby 2500. But with the smart folks on this site I am sure someone will be able to edjewmakate me. ABS module needed to be repaired. Torx screws were stripped so I had to remove the ABS pump. Looked like someone was already in it, 3 of the screws were stripped, bolts that mounted the pump were far from tight...same for the brake lines. Brake lines were open for 2 weeks. Filled m/c and pumped the pedal. No fluid. Tried my trusty vacuum pump...nada. Lost my pressure bleeding tank, so I got another one. Manual says to use 25-30psi. Pumped it to 30psi. Got lots of air. Keep at it til I had good, bubble free streams.
Here comes the huh?...
Set tank at 30psi. Open left rear bleeder. Get a stream...about double what you would if you were pumping the pedal...then it stops. Crack the right rear bleeder...nada...crack the right front...same stream as the right rear. Crack the left front...nada. only way to get fluid from the left is to lightly pump the pedal...did this while leaving the pressure on it. After pumping the pedal both lefts will bleed. Just out of curiosity I tried the rears...nada. My scanner software has the ability to perform the automated bleeding procedure...which I did several times.
I thought that with a pressure tank applied you could push all the fluid out of the m/c just by opening a bleeder and waiting...
Sorry for the length..