JD LX277 parking brake wont lock

My JD LX277 wont lock the parking brake. i can pull out on the handle and nothing happens. I've looked at where the rod goes and it's not moving the mechanism. I'm still not sure how the lock is supposed to work. I think the problem is because the parts are too rusted up (and rusted out). Does anyone have the same problem? Any suggestions will help. I am willing and able to modify to degree if needed. Thanks!