Old post. No replies? I snapped off the same bolt this morning. Stuck a grade 8 in there until I can track down the OEM bolt. Since a bolted connection is designed to clamp the load, with the amount of holding power due to friction directly proportional to the torque of the bolt itself, clearly it doesn't matter what bolt is used. (In this case, it's only torqued to 40 or 45 foot pounds.) Keep in mind that torque wrench accuracy is ~30% off. So, what is special about the OEM bolt? Well, it did have a taper on the button head side, keeping the bolt from clanging around in the bore if the force impulse applied to the connection exceeded the clamp load. Just say'in.