Miata seat belt bolts
 

I am looking for a set of seat belt bolts for a 92 miata. Or if someone could tell me the thread pattern and size that would work to. I did some searching on the web but found nothing. I am looking for the bolts that hold in the seat belts to the trans tunnel and the loop to the outside of the car as well as the large bolt that holds teh ratcheting assembly into the seat belt tower.

If I remember correctly, one or two of those seat belt bolts are standard, I could be dead wrong though.

Anyways, grab another bolt from the car (like the other seat belt) go to the hardware store, and find a nut that fits them. Look at the label on the nut box, and find the corresponding drawer of bolts. Get the correct length, and buy it. I also think seat belt hardware is hardened.

I would go to the hardware store and pick some up if I had not traded my factory belts with all the hardware for a set of 5-point harnesses. I have a box full of metric bolts and a decent amount or standart bolts laying around the garage but none of them fit. The side bolts are almost the same size as a 14mm but they are a little bigger and fine thread. The other bolts also have a weird bolt size on the seat belt tower I tried all the bolts I have and nothing. If anyone knows the thread size I will go buy them tommorow.

a little bigger than 14mm would be 9/16 then, if it is indeed metric. Different pitch bolts of the same size (such as 14x1.25 and 14x1.0) are drilled with different size bits, so if your 14mm bolt seems a little small, it's probably 14mm still, just a finer pitch. If you have calipers, I bet you'd find the I.D. is either .4724 (14x2) or .4921 (14x1.5). Those are the only 14mm sizes my chart has, if it's bigger than .490, it could be 14x1, smaller than .470 would be 14x2.5.

The reason for all this is because I highly doubt someone has a list of all the seat belt hardware sizes, it's a bit of a weird question, ya know? I'd love to be proven wrong though, it'd make it much easier on you.

Thank you that information is going to be very help full. Ill go to the hardware store tonight and pick up some 14 mm bolts in diffferent threads and if they don't fit I will mic them and post the readings if so you could possibly help me find the size. My buddy is a machinist and I am going to see if he can let me borrow a thread gauge tonight and go from there. Thank you curly for the help so far.

When you say 14mm, are you referring to the major diameter of the threads or the bolt head size? A 14mm bolt will generally have a 17mm head.
I may be mistaken, but I believe the belt hardware is standardized among all manufacturers to be 7/16" SAE fine thread bolts.

I was talking about the size of the bolt head I didn't know the actual bolt size I think the major diameter of the threads is 12mm but I am going to measure tonight. If the bolts are 7/16 fine thread that would make good sense. that is why the standard 7/16 bolt I have will start but won't go in you can tell they are not the right thread. I will post more info tonight.

Oh yeah, good call about the bolt heads. And I was right about the standard hardware! Sweet.

Ok I measured the inside diameter of the bolt hole it is .410 or close to that the 7/16 bolt I have is .432 outside diameter and .360 inside the threads. Dose this seem correct or am I way off. Also dose .410 sound correct for a standard size bolt.

.390 is the drill size for 7/16-20, I bet that's it. Measuring the minor diameter on bolts is always wrong as it's at an angle. So that 7/16 bolt you have doesn't fit? It's probably 7/16-14, get the fine thread edition.

Ok it is snowing like crazy here in MD so maybe sunday I can get out and get some bolts the local hardware closed early tonight so I could not get any bolts to try.

I've been through this before. Definitely 7/16-20.

Sweet thank you now as soon as the plow trucks make it to the back roads I can put them in.