peugeot 206 brakes?

the neighbour got me to look at his 206 with only one brake circuit working we tried bleeding the circuit in question but no difrence , we changed the master both circuits work to the point of locking but the pedal is almoast on the floor at the point of lock up, my 306 has plenty of exces space between the floor and pedal at lockup, is this a cause for concirn i am sure theres no air left in the system as we used over half a galon of fluid.