Just did this service on a ZT HD 60 with 960 hours. I found that the 1-1/8 socket I used for the nut was the perfect size for gently tapping out the lower needle bearing and the seal underneath. The seals are only lightly pressed into the frame and came out easily without damage. Since the lip seal rides on the outside of the spacer at the base of the spindle I wire wheeled them clean and smooth before reassembling with a touch of grease.
That's because it didn't need to be replaced. But it's easy to do, just take an extension bar and drive it out from the top it should fall out the bottom and the seal will fall out first.
