i got a problem with air in my brakes i think. the pedal is real spongy, and goes tot he floor. i bled them a million times, and even used one of those pumps that hooks to the bleeder and pulls air thru. and i always get air bubles. i inspected the lines and connections, and i dont see anything loose or any leaks. i replaced the master cylender, and it didnt do anyhting. is there something im missing? the brakes stop the truck, but they will never lock up, and it stops really slow. thanks for any help.