See stevebfl's solution: http://www.peachparts.com/shopforum/showthread.php?t=53165&highlight=cut+screws

If the tumbler is out (don't know from your description), use a screwdriver to turn large slot behind tumbler kinda vertical.

__________________
The Golden Rule

1984 300SD (bought new, sold it in 1988, bought it back 13 yrs. later)