Mechanical WW Elgin 760 (761) barrel - seeking advice

[klevay]

I'm servicing Elgin 761 automatic movement that has a mainspring barrel and a ratchet wheel as an assembly. Anyone familiar with this movement knows that the ratchet wheel is mounted underneath the barrel and the movement does not use a screw to hold them together. I tried to pull the ratchet wheel from the barrel's arbor but it doesn't come off. The Elgin service manual recommends to leave the barrel alone and do not disassemble it during service, but the ratchet wheel still has to come off. Please advice on how to proceed in this case? Is there a special tool needed to take apart the barrel and ratchet wheel?

 

[flynwill]

I've serviced these, and I have pictures of the disassembled barrel, so I'm pretty sure the ratchet wheel just pulls off. I certainly don't remember doing anything special. I believe that there is either a flat on the mainspring arbor to prevent ratchet wheel from rotating, or the arbor and center hole of the wheel are tapered.

If you put the assembly ratchet wheel down on your bench and then press down carefully the barrel itself I think you will find that both the barrel cover will pop off, and the ratchet wheel will be free.

When replacing the mainspring mind the fact that it winds the reverse of most watches.

 

[klevay]

I'm pretty sure the ratchet wheel just pulls off

Will, thank you for the encouragement. I was able to take it apart by using the flat nose punch and carefully pushing the arbor pivot through the ratchet wheel hole. Turned out that the wheel has a "neck" (or whatever its name is) that sits firmly in the arbor hole of a barrel (see picture). Pushing the arbor opens the lid of the barrel on the other side and the mainspring can be removed.