No rear brakes 72 Swinger

Hi, I have a problem with no rear brakes on my 72 Swinger.

Technical

74 front spindle Actually replaced the whole K Member
76 Cordba 11-3/4" front disks and calipers
using a manual brake set up 2 bolt master cylinder from later model Mopar
New disk brake proportioning valve
81 dippy rear brakes
All new brake lines
All parts listed are NEW

Problem no rear brakes.

I have bench bled the MC
Bled the brakes starting with RR
tried resetting the proportioning valve
Good hard pedal

Every thing seemed OK till I noticed the the front disks worked fine but I had no rear brakes.

When I remove the rear brake line from the proportioning valve and apply the brake I get no fluid coming out of the proportioning valve.