How is the wheel replaced

A handy person from florida says:

date: 10-22-09

How to you remove the old wheel?

date: 10-23-09

You probably need to replace the whole wheel assembly. If you need to replace just the wheel you will still need to remove the whole wheel assembly from your sliding door. Once you get the roller assembly out of the door you should be able to work the wheel out of the housing for replacement.