After three years, the bracket locking the snowblower’s muffler bolts broke, but this time I saw the bolt pop out of the muffler, fall to the driveway, and lie there sizzling in the slush. I tightened the remaining bolt and completed the mission.
The OEM bracket was thin sheet metal and broke across one bolt hole under the head. I sawed a rectangle out of a defunct PC case, then drilled clearance holes:
Bending two corners upward locks the bolt heads in position. I started the bends by clamping the bracket in the bench vise and whacking the corners, then finishing the job with a drift punch after installing it:
Of course, I renewed the Never-Seez on the bolt threads; they obviously weren’t corroded in place!
For whatever it’s worth, the many spot welds joining the top bracket to the muffler are doing just fine.