brakes on my 02 pontiac aztek are bad?

[Dave M]

i just changed the brake caliper, i put all bolts back on, i used caliper lube, every bolt is tight and correctly placed. i bled the brake lines and the brakes tightened up really good. i proceeded to test drive my car, but when i started the car the brake pedal immediately lost pressure and went right to the floor. it can brake but only if i press the pedal all the way down and when i lift it up a centimeter, the car moves. what is happening???

 

[melsg5]

assuming you have no leaks, how did you go about bleeding the brakes, it sounds like you have air in the line or the master cylinder may have failed.