Does anyone know what the markings above the 2 mean? The bolt is used to hold on the horns to the fender. A body shop replaced the bolt with another one and I wondered if it was even worth my trouble to put this one back in. They used a 9.8 grade bolt which I assume is overkill for the application but otherwise fine.

 

Here is what the back looks like.

 

WAG but i'd say it's a makers mark or IDs the type of fastener and not a grade mark. i wouldn't worry about it if it requires any effort at all to replace.

 

Ed is right on again. And oddly enough, it may be from his neck-of-the-woods. If I'm correct, St. Louis Screw & Bolt (Wellington, Ohio) uses marking similar to that. I don't know thier markings that well, so I have no clue what the "2" is all about, but I seriously doubt that it is a grade marking.

OEM fasteners rarely get grade markings (except the metric ones. In all my years in the fastener industry, OEM hardware almost never got grade markings (such as hardware store consumer variety fasteners get).

 

Thanks guys that gave me a little insight. As for other bolt markings, I've seen suspension bolts have 10.8 markings and fender bolts with 9.8 and those are OEM. So if it has a grade on it does that mean it's metric?

 

Those are ISO/metric markers for bolt grade, indicating minimum shear and elongation strengths. 8.8 is fairly common, and is similar in characteristic to SAE grade 2. 9.8 is better, more like am SAE Gr. 5, and 10.8 is better yet, more like an SAE Gr. 8. Of course, there are fasteners even better than that. ISO markers use higher numbers in some of those instances, while most SAE are graded "Super" or have no grade markings at all. Since the head markers tend to create stress risers and in such high-strength applications any potential weakness is avoided. The bad part is that unmarked fasteners can be either plain junk or superior to anything you'll find at the hardware store. The only way to find out is through destructive testing.

 

Destructive testing? Sounds fun.