hey guys, im having problems bleeding the brakes in my 1991 7.3 f250 .

when i bought it the guy mentioned that he had purchased and installed new calipers and master cylinder and what not but never bled the lines, i cant tell the parts are new and i have no leaks that i can find along the brake lines.

i attempted to bleed the lines with my pneumatic brake bleeder and have had no luck pressurizing the lines but the tool seems to work perfectly fine.
i have gone round to every wheel but still am getting bubbles in the lines while using the tool.

i read other posts on forums about people having this same issue and having some luck here and some luck there but never read from anyone that it worked perfectly.

non the less i cannot get any pressure out of my lines and feel that anything i try now is a stab in the dark..

anyone have any ideas? i am not sure where to continue now and have a big heavy truck being used as a daily driver with poor breaks.

the peddle goes all the way down to the floor, works(applies breaks), but when pumped a few times to build pressure in the peddle the breaks lose majority of the stopping power that its already hardly holding onto.

any help is greatly appreciated