[Gav]

The problem that you have is that you need to match the master with the calipers.
It sounds like the front calipers are not getting enough fluid (cylinder too small) and the tears are doing most of the work.
Try ringing racebrakes, hoppers stoppers or a reputable brake shop near you, tell them what you have and let them make a recommendation.
Personally, Howard from race brakes ph 03 96877222 is fantastic to deal with.