Hawk 250 rear brake "failure"

[Redbookaudio]

While enjoying massive acceleration after getting the carb tuned up, I needed to apply brakes and the rear brake pedal went to the "floor" with no response. Now I know why they say to check your nuts and bolts before every ride...and yes I will get some Locktite... the bolt on the rear brake lever had come out at some point on the ride and I can't find it.
My question is, does anyone know what size bolt, nut, washer I need to get the rear brake pedal hooked back up? Something I can get at the hardware store? Thanks! Chuck