Fender bolt question

[welder47]

I have a stripped out nut for the front drivers fender, Its on the top rear of the fender. I can make one up easy enough, BUT what thread is that thing, not one single tap I have seems to be the right thread for it, 1/4 is too small and 5/16 doesnt seem right either???

 

[68sportsatelliteragtop]

Pretty sure it is a 5/16". Bolt has a 1/2" head right?

 

[welder47]

I thought 5/16 was it, the bolt is rusted right away so I am going by the thread on the pass side of the car, just doesnt seem to fit right and its not fine thread, dont have a bolt to go off of either, both are missing. I dont think there is a size in between the two and it sure cant be metric in 1968.

 

[rrunner]

5/16 18 tpi

 

[Meep-Meep]

It's either 5/16 - 18 or 24. I think one of these locations has a stud originally so it might be 5/16 - 24 in the body with a 5/16 - 18 nut.