Here's an interesting one. On my 85 300td wagon, the seat belt mechanism locks up about halfway when I pull it from the door frame. It locks up and I cannot pull it further and it will not retract. Stops when its about at mid chest length. I usually remember to put my seat belt on after about a block from home (I know, bad habit) and the only way to get it to work properly (rarely) is pull over and jiggle the heck out of it to allow it to retract and then retry or.... towards the end of my commute I go over a pretty steep bridge and the seat belt releases its lock by itself on the downward slope of the bridge. Strange but true

I have yet to go into the mechanism to search for clues. Any first hand experience with this type of issue?

With a recent change in Florida law, where LEO's can pull you over for just not having a seatbelt on, I find it troubling to have an "sometimes" inoperable seat belt assembly