Thanks for getting back to me,unfortunatly the bearings were rusted solid so I just through the lot away.I sent mine back to Alko because I thought that they were crazed but they returned them cleaned up as new with the instruction that they were contaminated with diesel fumes and to clean regularly the ball and pads with emery.
It may be worth a try with emery or send them to Alko and see if they think that replacement is needed.(Very quick service)
They aren't cheap but are supposed to last 30000miles of towing