I don't remember that well just how the clutch failed, but a couple of years ago there was a rash of new clutch failures from one particular brand of high performance clutches. It turned out to be from installing the wrong slave cylinder at the time of the installation. The slave cylinder was furnished by the clutch company as part of the package. Evidently the Zetec slave cylinder is very similar but enough different to be not compatible. You may want to search back and see if any of those experiences fit your problem.
