Brakes acting strange

[Anzee]

Hello!

My 74 manta (and myself ) has this weird problem - brake fluids is transferring from the front to the rear reservoir; letssay for 60 miles of driving and braking (mostly city) the level of fluid in front reservoir drops and rear rises for around 2mm ...

brakes are stopping the car quite normally, only the travel of the pedal is a bit long (it does not become hard almost to the very end of the travel)

i guess this is a leaking master cylinder problem... am i right?

thanks for help!

Anze