I think I saw this on another thread somewhere, I don't know if it was your typewriter or someone else's.  But what his machine had was a crack on that side between the front and rear parts of the carriage.  I think the carriage had something like what we sell here--JB Weld.  The machine was doing fine after that.  I recommended welding as a more permanent repair, but alot of work is involved getting it done.