1988 Chevy Suburban no brake fluid getting to the wheel cyl

I just replaced the rear bearings and seals then moved on to the brakes, the reason I took the rear axles apart in the first place, I replaced the shoes, wheel cylinders and the short brake line to the drivers wheel from the back of the rear end.
After I put the drums on I started to bleed the brakes. I now have no brake fluid getting to the wheel cylinders. I took the line off that goes into the valve on the rear end and when the brakes are applied no fluid comes out. I went to the master cylinder and, removed the lines, got fluid to squirt out when pumped. I found another valve box under the radiator. I was able to get fluid to come out of it on all of the lines. Went back to the rear and got no fluid, but now a soft pedal to the floor. I kept the master cylinder reservoirs full the whole time while following the general brake bleeding rules.
Short of ripping out all of the brake lines and replacing all the valves I don't know what to do. Is this bis expense the only way to go or am I missing something in my work? Could you tell me how I should have done my brake work from start to finish for this vehicle?