I had the same problem once (upon the time...). The workshop people told me that without the push rod 'play' the fluid can't return to the reservoir. Every time the pedal is pushed the system will fill up until the pads/shoes stays solid aginst the disc/drum. Exactly what happend to me.
Goog luck with yours smile

-99 4/4, 1.8 Zetec, Indigo Blue, 2-seat, Suplex RS
-04 Citroen Pluriel, 1.6 Sensodrive, Met Orange