When I did mine I ordered an extra washer that goes under the seal, put it on top of seal than a long peace of exhaust pipe and rubber hammer drive them home.
With alittle oil on them I was able to push the bushing in with the washer and pipe first by hand.
Thanks for the tip! I don't have an extra washer, but I just read a suggestion about using a 1-1/2" coupler. Same concept, different component and one I can pick up at the store today
I did mine last week and used a 1 1/2 schedule 40 coupling and ground it down to fit inside leg. used it and washer to gently slide bushing in place then washer and seal and tapped it home.
What I would up doing was getting a 2-ft piece of 1-1/2" ABS pipe and, because it was slightly too small to slip over the upper fork leg, I cut a slit down the side of it with a circular saw which allowed me to spread it open enough to get it over the leg. I drove home the bushing first, then the seal. It worked out great.
Be sure to clean out the retaining ring groove, and the retaining ring itself. I did this by holding the fork leg upside down and taking som steel wool to the groove, then wiping with a paper towel.