Lane, a friend of mine suggests that once you've gotten the fan case off you might want to go ahead and replace the rear bearing and finger spring.......or at least “re-spring” the finger spring while it is torn down that far, clean all the dirt, dust and grime out of the motor housing and stator windings, and put an ohm meter on that armature and do a commutator continuity check as well as a check for short to ground. As for the stuck fan case, when looking at the machine from the front, there are two guide pins in the fan case. One is situated just above the safety/speed switch wiring pass-through and the other is situated just above the most outboard screw hole on the opposite side (the left side as you are looking at the fan case from the the front). It is best to focus on separating the case halves at these two points, since that’s where there is most likely to be the greatest amount of adhesion, and splitting the case halves elsewhere will likely result in bending or breaking these guide pins. So, as someone has already suggested, a sharp, flat blade instrument is needed, but I’ll caveat by limiting it to no more than 3/16” wide. Gently tap it into the case half union just above the safety/speed switch wiring pass-through, and give the instrument a 90 degree turn. Use a second instrument and gently tap it into the case half union just above the most outboard screw hole identified earlier, and give the instrument a 90 degree turn. The front case half should fall off easily. The remainder of the task should proceed as normal. Hope this helps.