Brake problem?

[nismo1003]

I have some brake problem, I bleed for all 4 line for all 4 wheels Properly ( fill up before it get emty) so I am sure no air in side the line. but the pedal still can reach to the floor? but the reservior hold the fluid so I don't think there are any leak? what other problem can cause that? no matter if the engine is on or off, the pedal still can reach to the floor? what does that tell me? do I have a bad brake booster? I have a bad master cylinder? if so? can I service them? or I have to get a new one? does anyone of u had the same problem before? please share what u know ?? what I should do? I took off the brake cylinder , I touch the brake booster?is the brake booster piston suppose to be loose like I can move in and out? or is it a broken one?