okay what i did was just took the pads out and pushed the pistons back in to the calipers,then just put new pads in.Made sure brake fluid was topped up and put everything back together then went to try brakes(with engine running) no pressure at pedal whatsoever.So bled brakes as well as could still no pressure.Bought expensive master cylinder(thinking old one probably blown seals).Put that in changed vacuum pipe from servo as well,now only a little bit better, i am sure it,s just air in the system but shouldn,t the pedal be hard due to the pads taking up extra space.If i,ve missed something plz help.