73 Cuda-no fluid to rear brakes

[YellowstoneYeti]

I've got a 73 Cuda that I have had since I was a teenager. I made it into a nice ride and then life got in the way and she went into storage. Fast forward 30 years and I'm finally getting around to working on it again. My present project is the brakes. I have basically replaced or rebuilt the entire front disc/rear drum stock setup. New master cylinder, lines, hoses, calipers, discs, etc. My problem is that I cannot get any fluid to the rear wheels. When I put the new lines on, I pulled the stock proportioning valve apart and cleaned/inspected it. All the o-rings, gaskets, etc. were in good shape so I did not replace them. Even with the rear line removed, I can't even get a drip while pressing the brake pedal. If I loosen the lines from the mc to the proportioning valve, they will leak, so I'm getting pressure from the mc. I suspect the proportioning valve is bad? Did I miss something when I was in there? Searched the internet and can't find a stock replacement. I found this one on ebay-http://www.ebay.com/itm/390486260576?_trksid=p2055119.m1438.l2649&ssPageName=STRK%3AMEBIDX%3AIT Has anyone used one of these with success or failure? I know about the Wilwood adjustable but would like to remain as close to stock as possible for now.  Thanks for any help or suggestions.

[Chryco Psycho]

if fluid goes into the proportioning valve but not out it has to be that , so either it was assembled wrong or wrong parts inside , something ....
I have not tried what you are looking at .

[Bullitt-]

There's a fail safe feature in the proportioning valve that could be causing your issue...
 
Service manual says to make a tool to hold the valve open... similar to this pic I found

[YellowstoneYeti]

There's a fail safe feature in the proportioning valve that could be causing your issue...
 
Service manual says to make a tool to hold the valve open... similar to this pic I found

So if I understand correctly, I leave the spring on to extend the rod, fill and bleed the system and then release the spring?

[Bullitt-]

So if I understand correctly, I leave the spring on to extend the rod, fill and bleed the system and then release the spring?

That's the way I get it... the device holds the valve open so fluid can get to the backside till there's enough pressure to hold the inner spring back.
 

[Zero]

Also you can pruxhase a tool called a proportioning valve bleeder that virtually does the same thing. "Death to prop valves!"

[73440]

Photos taken from 73 manual, looks like that tool is not needed if gravity or pedal bleeding is used due to low or high pressure.

[YellowstoneYeti]

Thanks for all the info.  It is much appreciated!