Now I understand. Thats a tough one - They normally just slide out freely so yours must be galled or seized to the bearing. If I recall it correctly you have the stud that the impeller bolts to. You might have to build some type of slide hammer out of scraps that will thread onto the stud and tap it out. I built a similar one for removing the air valve on the shock, built out of old pipe fittings. Might work. Soak it is some penatrating oil first. Gun powder solvent works great too. Pics in my gallery of the puller. Hope this helps. Cam.
PS it could also be possible to knock the bearing balls out with a punch so you could at least get the thing out of the case to work on it. If I recal it is a blind hole (someone correct me if i am wrong) so the balls wont go anywhere. Ca,