Having read the manuals it seems like a seal driver tool is necessary and often the manual suggests using a cast-off fork leg or something like that for the job. Since I have no fork legs to spare I take the fork leg to a shop. This saves on the disassembly labor and I don't have to search high and low for something that will work (or not).
Current: 1988 BMW R100GS (the 'numberplate' model)
Past: 1987 Yamaha XT350
1983 Honda CB900F
1980 Honda XL185S
1979 Suzuki GS425E