Did you try to adjust it where there was no free play in the pedal? This would help prove it is disk friction causing the problem. Then to figure out what is causing the friction?
The cause could be pilot bearing.
A bad pilot bearing could spin the shaft and cause the problem...but would not have much ability to apply power to the wheels. Push in the clutch... put it in gear...then bump the starter and see if the car rolls. If it does I would say it is related to disk friction for sure.... not pilot bearing.
