John,
The increased preload was applied to the bearing from new. The engine and box were removed for other reasons there was no indication that the bearing was deteriorating before the strip down. In view of how its been overheating and thrown most of its grease I doubt it would have lasted much longer before starting to make some complaining noises. The worrying thing is what to do now as all my previous CRB`s have failed by way of the bearing coming away from the plastic slider section with little or no evidence of loss of lubricant. ???????????// Have I made the situation worse by applying more preload, it would seem so ??????????/