If the shaft isn't too badly scored by the seal you can use emery to restore the mirror finish. Start with something like 400 and
work up to 1200 or so. Chuck the shaft in your drill and it's a quick job. The
water pump on my
2GM has over 500 hours leak-free since I did this.
Don't overdo it though or the shaft diameter might end up too small for the seal. I did this on a
gearbox rear seal and had to fix it with a Speedi-sleeve.
If you do fit one to your WP you may need a longish piece of pipe or tube to press it on, and this will require lots of care to avoid scoring the sealing surface of the sleeve.
Cheers, Graeme