76 450slc Brake problems
 

replaced front brake hoses, unable to loosen rear hoses,
new front and rear calipers and rotors. bleed fluid until old dirty fluid was clear.
brake pedal still goes to floor unless pumped.
car won't stop with brakes just slow down.
could the car need and master cylinder or booster?
how can you diagnose what the problem is at this point?
please help?:(