Vendo 81b

I recently restored a Coke vendo 81b. All was working well until last night when the vending mechanism seemed to bind up. The vending handle of the coin mechanism (which is set on "free play") has lost the ability to travel through the path without binding up. I attempted to inspect the inner workings through the door liner inspection ports and all seems to be in place. Any suggestions out there as to what may be the problem before I have to pull the entire door liner off? HELP!!  Thanks, Kevin