I have seen standard bolts break. Even a grade 8 bolt broke on me.
The square tubing hole was honed out which help to wear out the bolt.
My solution was to cut off the end of the square tubing and drill a new hole, then I used a hardened clevis bolt. Here is a picture. The washers were necessary to cover the gap between the cotter pin and the tubing.
2007 Country Coach Tribute 260 Sequoia
40' DP w/Cat400, F494513, Lithium Battery & Solar
Live next to Yosemite