[burnin oil]

Over travel or wrong throwout bearing can cause damage to the pressure plate. Where does the clutch grab? If it is really high on the pedal and you push the pedal to the floor I am betting this is the problem. Like someone else said funny things happen in operation. My trucks clutch pedal refuses to return all the way up and will let the throw drag if you don't tap the pedal up with your toe. I unhooked the linkage and everything is smooth in the pedal and has full returns. Zbar and linkage seems fine and not to worn considering age. Hook it all up and the bearing will drag. Sometimes you need to look real close.