I did bearings and seals on the hubs of my 1951 77 row crop last year. I have the big heavy hubs. I got the seals and wear cups from AGCO.
K738 wear cup
163101A seal (my seal measures ID 3" OD 3 3/4" width 1/2")
you can find the seals else where but the wear cups (from what I found) are AGCO only