brake clyinder doesn't pump to REARS!

[vanguard]

i just put on a new s13 booster and a s13 brake cylinder, i bench bled the cylinder with lines and put it on carefully back into the car, started bleeding and nothing would come out the rear driver caliper, so i moved to the passenger rear, and still nothing, im aware that a single line from the cylinder splits into two for the rear brakes... and the cylinder isn't pumping fluid or air or anything through the rear line, this happened to 3 clyinders it only pumps to the front right and left calipers..... what am i doing wrong???

P.S. Im looking for responses from REAL TECHS,... ive trouble shot everything... if questions i have all the details but basically the clyinder pumps out to the front right and left lines only and the line for the rears nothing...

[projectRDM]

Was the cylinder bench bleeding fine from all ports? I just had an S14 do this, the proportioning valve went bad, cutting off fluid flow to the rear chamber. S13s have an internal valve so you may need to exchange it.

[vanguard]

hmm none of the 3 cylinders seem to bench bleed and/or flow from that last hole which is the rear brakes hard line.