sunds like what was happening to the rx7, i reckon that was the master cylander lettin fluid back up to the resivoir when your foots on the clutch. could be miles of not but might be on the ball
i dont think this is the problem as its getting good pressure when the pedal is down its just all the free play before it.there is absoutely no pressure on the pedal 3 quarters of the way down at all. then it all comes on it at the end