Several years ago, I bought a ball joint separator tool from Harbor Freight. It was the best $20 I’ve ever spent there. I don’t use it that frequently, but it works great. It’s finally failed on me, but not so badly that I can’t keep using it.

While attempting to get a stubborn ball joint to come free of a control arm, the pivot pin sheared. Despite not being the thinnest part of the tool, it makes sense for it to be the part that broke first.

The pin sheared at the part that contains the spring and ball that lock it in place, so it was the weakest part. While I can just go to Harbor Freight and pick up another of these tools, to keep working on the car at the time, I needed to replace the pin with something, and the obvious, most easily attainable solution, is a bolt. That’s when I learned a little more about bolts.

The first bolt I grabbed was the same diameter as the original pin, and was an 8.8 rated metric bolt. I started using the tool, but before I was able to get the ball joint popped out, I noticed that the bolt was just bending. It’s the bolt in the middle in this picture. I replaced it with the bolt on the right, which is a 10.9 rated bolt, and as you can see, it didn’t bend at all. I knew that 10.9 bolts were stronger than 8.8, but I didn’t expect such a difference.

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-Dan