Can't help with the size but mine broke two years ago and I did an emergency fix with a cotter pin. It is still in there, never did make it more permanent and it has worked fine. Now that I have said this it will probably break next time I use it. If I do go more permanent I'll use a bolt. The linkage is sloppy enough that it won't know the difference.
Either option will get you moving until you can fix it right.
Paul