[quattrodave]

Pump the pedal method usually works better than bleeder tool (be that a push with air pressure or a vacuum pull tool) bit daft but have to ask you have you checked that the master cylinder is actually pushing fluid through both circuits as could be faulty on one of them ?

In fact have you bled the master cylinder if its got a bleed valve, you would need to do this if fluid went too low and a chamber emptied.