Cut one section of the plastic protective shroud on the back of the pump assembly–this will expose the motor shaft. Use a hacksaw blade, a jig saw, a rotary bit whatever you can come up with

Next with the pump cover removed drill a small hole all the way through the impeller and through the back of the motor housing. Drill the hole at least halfway out from the center of the impeller to keep from drilling into the seal seat.

Stick a screwdriver all the way through both holes. This will keep the impeller from turning without damaging it.

Loosen (not remove) the bolts that hold the pump assembly to the motor.

Use something that can really get a grip on the motor shaft and unscrew it from the impeller.

Now for the seal:

Sometimes the seal is impossibly locked into the impeller seat and you’ll break the impeller trying to pry the seal out before you get the seal to budge.

Inspect the seal and find the solidest part. Carefully measure from the center of that part to either the center of the impeller or to the outside edge of the impeller–or both.

Turn the impeller over and drill two very small holes 180 degrees from each other in the area you measured. Take two small nails and drive the seal out. I lay the pump face down and put the impeller on top of it to give the seal somewhere to go.

Seal all the holes with your favorite sealant and reassemble.