I have a 314 Cat that has been breaking the rod that holds the swivel in place #7 in this diagram. I have broken 2 in the last 500 hrs and noticed when I replaced the first one it had broken on a previous owner who used a bolt instead of the rod from Cat. I’m an owner op that tries to treat the machine easy and with respect. I haven’t hit anything while swinging. Has anyone else had issues like this? Could there be something else wrong that would make this rod break?
Something is causing the swivel not to swivel freely. Something is making it bind. I don't know if it's greaseable or somehow getting pushed out of alignment. If it greaseable maybe it has old hardened grease causing the binding?
It might be fair to think that a previous owner has had the center joint (swivel) resealed at some stage. I've little experience on the Cat make however I know many other makes have shims at the base of the center joint. Perhaps remove the belly pan and the base from the center joint and inspect that area. It sounds as though the center joint is binding within its housing causing these to snap. A simple case drain test will prove that the inner workings are OK but 100% sounds like it has been assembled wrong.....
One other thought. If you were to remove the pin that locates the center joint, you should be able to get a lever bar into between the hydraulic hoses and turn the center joint back and forth a 5 or 10 degrees.....with the machine shut down of course. If it takes a heap of effort then the internals need inspecting.