Citroen flywheel & release bearing

[Geeman]

My US spec '84 Turbo presented me with this exploded release bearing.  It appears the bearing came away from the centering tube it should be fitted too.  It's only held on by that sheetmetal ring that has tabs pressed around the tube flange.  I have no idea why it exploded like that but the rest of the system is OK.  Spigot bearing is good, albeit pushed back maybe 2mm from the crankshaft face, the nylatron thrust washer is still in place on the input shaft, the input shaft is in place by the circlip (I think the previous owner upgraded that).  The retaining clips for the release bearing to the fork had come off and only one was in the bottom of the bellhousing.

I have a complete new clutch kit coming from a UK supplier, including hydraulics.  Any thoughts on what could have caused this?

I am also getting the flywheel re-faced.  Question on this...there is no step to be machined on the flywheel?  Its a straight flat surface across its face?  I have read that its the Renault gearbox that requires a 0.5mm step, correct?

 

[Gis]

I had a similar issue some years ago Gordon. Cracked release bearing housing. It was caused by an incorrect pushrod (too long). Must have been changed by a PO for reasons unknown. That stuffed up the kinematics and overloaded the bearing housing over time. Especially so with the correct slave cylinder length adjustment setting as recommended in the service notes. It manifested in distinct shuddering on the clutch pedal before it eventually let go. Swopped the part for the correct one, replaced the complete clutch and release bearing, issue resolved. 

[Gis]

In other words, incorrect slave length adjustment and pushing the release bearing in too far/hard over a period of time, will eventually overcome the weld points of the bearing housing.