[M 4 FUN]

Hi everyone.
I bought a M3 this winter. I have a brake issue. the pedal has a long travel before the brakes are activated. We have bled the system several times but the symptoms are the same. the car had been stored for 17n years before i bought it and i wonder what the issue could be. the pedal is not sinking to the floor but it takes too far down. I have no fluid leakage either.
Any ideas?