splitty CSP dual circuit brakes

fitted a CSP dual ciruit master cylinder kit to my 1960 splitty pickup,2 new front brake pipes and 1 to the rear t-piece+2 rear flexi pipes,fitted it due to my old single cylinder leaking and with the intention of fitting disc brakes(eventually) which you need dual master to make em work right,tried to fit it using the drums all round set up(which i have been told will work by the supplier)iam sure the push rod is set perfectly,there is no fliud leaks at all and plenty of fliud coming through the wheel cylinders with no air bubbles just clear fliud but still have a crap pedal!!,u can pump up the pressure and pedal is hard half way down(suppose needs brakes adjusted,shoes all ok)then let off and pedal hits the floor likes air is in the system,just wondering if anyone else has done this and made it work or had trouble getting it to work