HOW TO CHANGE THE REAR WHEEL ON A MCCULLOCH RIDE ON LAWNMOWER?

Ive got an old yellow Mcculloch ride on and the rear tyre has come off the rim, ive taken the bolt out of the wheel but its still stuck on there ? Tried wd 40 etc, dont know what to do next. Looked on e-bay for a manual but no joy there. Any thoughts out there? Richie