Seat belt bolt sizes
 

I recently ordered a Retro Belt system for my 86 Custom Deluxe. The previous owner removed the bolts where the buckles are with no issue, but broke off the bolts where the retractors are. I drilled and tapped those to 1/2" so I'm good there. The threads on the buckle bolts need to be cleaned out, but I know they are not 1/2". They provide a couple different sizes of bolts in the kit, but none of them seem to fit. I thought they had switched to metric for these bolts, but I'm not sure what size they are. Any help?

Re: Seat belt bolt sizes
 

I may be wrong but seems like I remember them being 7/16 Fine thread

Re: Seat belt bolt sizes
 

Re: Seat belt bolt sizes
 

That was it. The threads were pretty dirty, but once they were cleaned the bolts went right in. On the last retractor one now. I can't get the stupid tap started in the hole I drilled out. I used a 3/8" bit, but I was supposed to use a 27/64" bit. 3/64" you wouldn't think would make that much difference...