I think that a lot of slave/release bearing problems are caused by sitting, with the engine in gear and the clutch pressed. "Old school" driving instructors told us to disengage gear and sit with the vehicle in neutral, with the handbrake on. I've always driven that way and have never (touch wood) had a slave/release bearing problem with any of my vehicles. ( I know that modern driving instructors tell students/learners to be in gear, at the ready to move off when road conditions allow. ) IMHO The pressure generated on the release bearing, in that extremely hot environment would soon lead to loss of lubrication and failure of the materials, particularly plastics.
