Finally junked it when the driver's seat literally fell through the floor,
    due to massive-- you guessed it-- rust.

My first car was a 1964 bug.  Junked it (actually,
sold it!) when the driver's seat fell through the
floor (not with a bang, but a whimper).

Different story, same car:  Driving a washboard
road in rural Maine for hours.  Stopped for lunch.
Car wouldn't start.  Pulled up the back seat and,
you guessed it: a hole in the floor where the battery
had been.  Roll started it, drove on.

--dan