I was faced with a similar problem, and resolved it by making my
own keys.  I found some old keys that fit the locks, but would not
activate the lock.

Since the locks themselves are easily removed, one can get a good view
of the lock mechanism with the key inserted and visualize how it is
supposed to move the lock mechanism.  Simply file the old key so that
it will move the lock, and you will have keys that work perfectly.

Bruce Clark