01 2500 brake issues
 

ok brakes pretty much quit on me. pedal would return real slow and just had the bottom of pedal for brakes. took advice and changed master with no luck at all. so changed booster and after bleeding was getting brakes when all of sudden pedal went to floor and wont return . took mc back off and tried pushing booster back and it will only go half way and is spongy. all lines are clear and off when im doing it. could this be bad booster out of box, or do i have other issues. this is my farm truck and need it going badly. not sure where to go from here

Should have hydroboost. You've got air in the lines or dirt....