Water pump seal/rebuild

[RSSSfan]

I have had a correct date coded water pump and rebuild kit for the L35 396 in my 69 Camaro for many years. A buddy gave this to me a long time ago, and I am just now getting around to rebuilding it. I pressed the old parts out of the housing without issue, and successfully pressed in the new shaft and sealed bearing assembly. However, when it came time to install the spring loaded seal, I had a problem with it coming apart. I used a socket that was just large enough to fit over the outer edge of the seal where it seats in the housing, but the other part of the seal is an interference fit on the shaft. It pulled apart and ruined the seal when I did this, so my first question is where can I source another seal? My second question is, should I press on the inner sleeve that presses over the shaft this time? It would be great to talk to someone who has rebuilt these pumps before. Thanks in advance!