I don't know. [stop - your mower may be under warranty and may qualify for free repairs. check with your owner's manual for a free number to call for information]. before working on it, make sure the battery is removed. consider turning it upside down to inspect the wheel. if there is no physical blockage stopping the wheel from turning, you could try spraying the bolt with WD40 or a few drops of motor oil. if the wheel turns, lubricate it again and do the same to the other wheels. if it does not turn, the wheel will have to be taken off.