I have replaced MOST of my brake components Master cylinder Brakebooster Wheel cylinders pads and shoes spring and self adjuster kits. I have bench bleed master cyl. bleed all lines cheaked for leaks found non. When the truck is on and i press the brake it loses presure till on the floor.Any ideas?

 

You didn't give the year of your truck , therefore we don't know if an anti-lock system is involved.
Some things you might check;
Did you adjust the self adjusters as close as possible before putting the drums back on?
Did you bleed the brakes in the correct order, RR,LR,RF,LF?
Of course when bleeding , you kept the master cyl full so it couldn't draw in any air?
Usually when you lose pressure as you describe, either you have a leak somwhere or there is air in the system or the master cyl is questionable. Let us know what you find.

 

yes and its always a good idea to bleed master cylinder be hooking up the lines to it