Loosing brake pressure on Vito -97
 

Please if anybody have any advice for me.
The brakepedal goes nearly all the way down to the bottom and if I push it again the pedal stops erlier. I have changed the mastercylinder and I have bleeded the system as usual with preessing pedal - open bleedervalve - close and so on but without result. The car is equipped with ABS - could that be a problem? The ABS-unit works properly on ice.
/Marcus