Need help on my 1990 Ford F-150

I replaced my brakes. (front) got them all good to go turn on my truck back out of the driveway and no pedal. so i thought.. okay guess i have to bleed them. did that, still nothing. bled it again a few hours later. had a front rubber line blow in my face. replaced the front lines (hard/rubber). bled them again. had the back lines blow. Replaced the back hard lines and rubber hose. went to go bleed them and couldnt get one of the bleeders out... decided to replace my rear wheel cylinders. While i had it ripped apart i replaced my rear shoes and drums. got all that one. Bled all 4 wheels in the correct order. Still no pedal pressure. then i went on and replaced the master cylinder. still nothing. replaced the power brake booster. Still nothing. in the end i gravity bled the whole thing for 45 minutes. no change.

so.. as a recap these parts are brand new:
Front brakes
Rear shoes/drums
Rear Wheel cylinder
ALL front/rear lines steel and rubber
master cylinder
power brake booster.

any idea why i'm still not getting and pressure in my pedal?

when the engine is off i get perfect pressure. soon as i turn the engine on, i instantly lose all pressure in the pedal. i dont know what's wrong because everything is brand new and there's nothign left to replace accept for the front callipers, but they're not leaking.

 

its possible you got a bad master cylinder or booster its happened to me

 

i don't think they're bad. because i replaced the two of them one at a time. and i have the same result before and after replacing them.

i just dont know what happened. all i did was change the front brakes and all of this kinda turned into a chain reaction. i understand why the lines broke they were so brittle and rusted. but i still dont understand why it wont work now.

 

what about the equalizer or the line goin to the booster

 

equilizer?

and by line going to the booster are you talking about the vaccume line that goes from the booster to the engine? that ones fine.

 

there is usually a box that the brake lines run to under the master cylinder or you might not have bled the master cylinder all the way