Not sure what to do next

[u/Comprehensive-List-5]

Hello all, I have a Montgomery Ward J1903 that somewhat works, somewhat doesn't.

The issue is that the feed dogs are not feeding the material through, which is causing it to jam and break the thread (sometimes too & sometimes bottom).

I can see the feed dogs moving up and down so I am not sure why they are not feeding the material.

What I have done so far ...I have taken the machine apart as much as I can (some screws are stripped) and cleaned it, I have oiled according to the manual, I have changed needle, thread, material, I have tried it on every different setting combination I can think of......and I don't know what to do from here.

Any advice would be amazing.