springfield model 67D pump issues

[Stewienb]

This shotgun has been a great gun over the years but it fails to pump when the trigger is pulled every time. Sometimes when its fired you have to use the button to allow it to pump. Seems like something simple but if anyone has any ideas then let me know. Even if you have dissasembly instructions, that would be great.
Thanks

 

[smoji]

It's likely the slide lock spring has been bent out of alignment or, less likely, broken.
Your best bet is to take it to someone who is familiar with the model and have the spring adjusted or replaced.