What I did was to chuck the spindle nut/seal assy. up in my vice. *Don't lean on the vice handle too hard, you don't want a oval spindle nut when you are finished*. I took an old wood chisel and ground it down so the blade was the same width as the groove in the nut. I also ground the edge so the blade was sharp. I then went to work cutting the old seal out. This is an exercise of FINESSE not brute force. Even though you won't hurt the nut, you don't want to be chasing it across the garage floor after every swing of the hammer.
After the seal had been successfully removed, I used the correct 6 point castle socket for the installation of the nut/seal assy. onto the spindle, to press everything back together. I inserted the seal into the socket, lined up the nut with the seal and socket. I then put everything down vertically on my work bench, (nut/seal down), and protected the top end of the socket with a short length of 2x4 wood. I then bumped everything together with a 4 pound sledge hammer. Again practicing finesse so I don't risk damaging the seal. Make sure you line the nut and seal up correctly because once the seal is in, it's in. I destroyed a seal with my first attempt at this.
The whole process took around 10 minutes for each assy. after I got the hang of it. I bought 20 seals and rebuilt 14 nuts for myself and some friends.
1941 G-505 Dodge WC-6, Command Recon.
1943 G-518 Ben Hur Trailer
1943 P.E. 75 Generator, 120 V. A/C, 2.5 K.W. - 4 K.W.