It's fairly easy to replace the fork from the top. You will have to remove the bolt that holds the fork in place (if it's still there). Once you remove the bolt you can slide the rod to the rear of the tractor. Be careful here, as the popet ball will fly out. (
Once you have found the ball and retrieved it from the floor
). Seriously just hold your hand over the hole when you're sliding the rod back to save yourself the grief. Don't ask ya'll know
If you loose the ball not to worry it's 3/8" dia.
Slide the rod back as far as it will go and remove the fork.