I took out my factory automatic brakes and put in some fourth gen manual brake/clutch pedals but the top bolt hole is empty and there's nothing to thread to. The original bolt came out of something threaded so I was just trying to figure out how I'm supposed to bolt it up all the way. I figure a palnut would be the answer but I'm not sure which one would work or how to even get one up in the hole it came out of in the first place. My uncle says that it's necessary to avoid warping the firewall so I figure I need it in a daily.

Sorry if this isn't the right board to post this on, I couldn't figure if it'd be in interior, transmission, or brakes since it's about the brake/clutch pedal assembly.