back brakes wont bleed

yeah i,ve tried to bleed with a front nipple cracked and with em both done up,just no fluid to the back,i,ve taken off the prop valve and disassembled it not sure how far that little pin at the top(valve)should move up and down,i swear its a proportioning valve problem,i reckon its seized or something,a company called inline tube sells them new on ebay for $80 i might just buy one