1911 Thumb Safety doesn't work anymore

[marklbucla]

I've got a thumb safety that will fail when the trigger is pulled about 3x the force with the grip safety pressed. It used to be the case that it would do it when the slide was off and the thumb safety was pushed higher than it should be, but would still function properly when the slide was on it.

Does it sound like the thumb safety needs replacement or does it likely need re-fitting?

 

[VHinch]

It sounds like it is worn to the point of not fully blocking the sear. Nothing to do but replace it.