Inherited a 1960's era JD AWR disk a couple of years ago. Decided I needed to pull it out of the fence row where it had been sitting since 1989 and see what condition it was in. Well to no great surprise the back two gangs would not turn. I've pulled them off and started to disassemble the gangs. One bearing, the one away from the gang nut, of course, is frozen on both gangs. I've encountered a short spool next to a bearing that is frozen on the gang bolt which is 1-1/4" square. This is the spool after the second bearing. All the spools, blades and first two bearing came off with almost no effort. This spool appears to have twisted slightly on the gang bolt and is wedged. I've been soaking it daily for the last month with penetrating spray. Spools are cast, so excessive heat and direct beating aren't a good idea. In addition to being wedged the void between the bolt and spool is packed with rust/very fine dirt. I used a small pick and removed maybe a quarter inch of this dirt/rust, then hit it with a high pressure water stream at the local car wash. The high pressure water didn't appear to remove any additional rust/dirt. I tried to rotate the spool with a chain wrench, won't budge. I'm thinking the next effort would be to apply rotational pressure with the chain wrench while someone else beats the nut end of the gang bolt. Nut in place and block of wood used to protect end of bolt. If anyone has other ideas or first hand knowledge I'd really like to hear from you.
By the way my dad and I replaced the blades on this disk in the late 1960's and this was the last time the gangs were disassembled.