1997 toyota corolla 5-speed manual transmission clutch problem

[fisherbuck]

So, I bled the system and got immediate results. There was plenty of pedal and it seemed like the problem was resolved. But then after a test drive of approx. 30 minutes, the problem re-ocurred. Once in a while, again, the clutch would engage when pedal was fully depressed. But I also noticed that if I shifted into neutral and pumped the clutch a few times, I would again have a good amount of pedal and a smooth shift like it should be. Is this still the master and slave cylinders going bad? I was told if the master was going, the pedal would go all the way to the floor and it would be a constant problem. Is there a remote possibility that I only need to replace the slave cylinder? Thanks again for any input!!