1963 GMC K10 stock BRAKE question-problem wont stop

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Again , I went through 4 master cylinders, new wheel cylinders and rubber hoses ( I realize that new doesn't mean its working) although I checked the function of each part , disassembled cleaned and went through everything at least twice. Front metal lines were blown out , ran a wire through them with no sign of any resistance or crud in the lines. Did my best to make sure the shoes all made contact with the drum and checked that they were expanding without the drum on. This is why Im simply going to the later setup and if there is still something not letting it stop, I know I missed something , although I doubt it. Might get the truck out one more time and pull the drums.