Hi,
I just joined the forum and noticed you message.
I hope I am not too late to be of help.
To change the PTO seal just unbolt the flange around the PTO shaft and it pulls right out.
The seal can be easily changed once the shaft Assy is out and on the bench.
It is really easy to do.
I am restoring a 9N and just did it on my tractor.
Good Luck!
Herald