When you press the pin in, it should retract the pawl like so



This is a bad tumbler that the key won't turn. I just soaked it in soapy water and jiggled the key a few times and it turned. Soapy water works great as a lubricant in certain situations.

__________________
85 300D turbo pristine w 157k when purchased 161K now
83 300 D turbo 297K runs great. SOLD!
83 240D 4 spd manual- parted out then junked