Hy oldsoul-65, you will have to find out what kit or parts were purchased, there is no way to tell, that I know of from the outside whether you have a drum/drum, disc/disc, or disc/drum master cylinder. You said you have bled the system till the cows came home, so you should have all the air out. Drum brake systems must have residual pressure valves, either built into the master cylinder, or added as inline valves. Have the three flex lines on the truck been replaced, they may be causing some of your problems, if they are collapsing from the inside. It may be the best idea to take the master cylinder off and dissassemble it to see what you have. then you can reassemble it, bench bleed it, to make sure both primary and secondary systems are functioning correctly, then reinstall and rebleed the system, good luck
