Here's an illustrated example of how I rig a motor for wheel removal. First I support the underside of the motor frame at two points on opposite sides of the axle. A good assortment of wood scraps is very useful here. You can see that one side is clamped, one clamp suffices.
For driving out the axle you need a round piece of steel with a flat end and diameter slightly smaller than the axle. A 8d nail is about the right size. I use 1 1/2 inch roofing nails that are an inch and a half long. You can see how I hold it in the photo. As I don't have a third hand, I can't show the hammer because the second hand is holding the camera.
Holding the nail I tap it lightly with a large hammer and gradually increase the force of my hammer blows until the axle begins to move. Be careful with the force, it takes less than driving a nail into a pine board. And be very careful to keep the nail vertical and centered.
The final photo shows the modified nail that I use. I cut the tip off with a hack saw and file to be sure the end is flat.
