strange clutch pedal feeling when driving for a while

[igralec]

Mate has a ACT organic clutch, it was ok last year when he last drove it but now after he been driving for a while, the pedal starts biting at the end and it's very soft and slow to disengage (almost doesn't want to return). He bled it a couple of times and it's not slipping, can't see any leaks from the cylinders either, any ideas what it could be?

[Jon]

My guess would be a failing slave cylinder. Even if there is no leak, the piston can get worn and gritty in its movement. I'm on my 3rd now.