How to aquire and fit a new bearing on the tub?

At the rear of the tub there is a large wheel with a belt. This is sticking and is hard to turn when switched off. It will turn then go stiff again. It is evident that the motor is free turning. Sometimes there is a grinding noise from the bearing. This tells me the bearind requires replacing. I am a retired field service engineer (optical industry) so I am quite capable of carrying out the repair. If I can obtain the parts.