I tried something tonight .I took a bicycle inertube cut it stretched it over the hub of the brake drum put a hose clamp over that , poured P B Blaster Down the tube crimped the end and put some air pressure on top of the liquid hopefully forcing it in the splines better it ran out the Backside...
I found them a the local John Deere dealer . The 4 seals all the same , 2 to the side turned back to back at least that’s what I’ve read they really look large , but they went by the serial number. All 4 was about 24$
Did your drums come off easy? I’m still soaking the splines with P B Blaster...