I am with Tim, find a mechanic to set the seals in and replace the shaft, bite the bullet, you will only have to redo the work again, which means new seals, again if you re-install that shaft. Take the pump to a shop. I think I was charged $25 to install the seals. And the water seal will or might leak just a wee bit at first, takes a couple of turns of the shaft to set it in place. Clean the whole thing and area up good.
Remember if you bite the bullet now, you can get another 20 years and countless miles out of it. cheap in the long run