Knock in the floorboard

[Lummix]

SO i noticed something today while driving, when i get on the brakes, i feel a slight knock in the floor board just in front of my drivers seat. It's not loud, or really even hard.

I got under the car and nothing seemed out of the ordinary...

Anything i should look for??

[Lummix]

Ok after a bit of trial and error...i think i've isolated the area of the problem to the pan directly below the driver seat area. Any idea of what is in there? I'm wondering if i broke a mounting bolt for the seat and if it's rolling around in the pan hitting my foot area when i brake.