1st, if a clutch goes stiff you have fitted a wrong clutch assy to a wrong flywheel, up to 2004 a luk flywheel required a corresponding clutch assy. After 2004 both a flywheel and clutch should be changed. If you mix and match the depth the clutch adjusts is too great therefore locking the pressure plate and no further travel. Hope this helps. williamsdiesels.com
Deano
June 2009