No fluid to rear brakes.

[oldie67]

I am a newbie so bear with me. I am the new owner of my dad's 67 chevy stepside 2wd. I am having problems bleeding the rear brakes. I had to replace both wheel cylinders plus new brake shoes and I also replaced the master cylinder. I have removed all the lines from the distribution block (prop valve) and blew air through all the lines. Still no fluid. I have also tried gravity bleeding but still no fluid. I read on another thread that my valve may need to be reset. I removed the distirbution block and removed the pin from it. When I look down inside the block all I see is a bar of some sort. So how can tell if the valve needs to be reset or replaced? My brake light on the dash is not on. It only comes on when I first start the truck but then it goes out. My truck is all four wheel drum brakes. Any help would be greatly appreciated.

Thanks,

Oldie67

1967 Chevy Stepside 2WD
350 engine
T350 Tranny
600 cfm Edelbrock carb
Edelbrock Rpm camshaft and intake manifold