JB weld won;t hold for long.
I’m having a hard time envisioning this, but it sounds like you might be able to thread and helicoil the 21/64" hole and accept a nonperpendicular bolt. You could use a washer under the bolt to better distribute the bolt’s load on the (I assume) cast bracket. I’m saying helicoil because 21/64" is slightly larger than 5/16", and I’m assuming that you’ll need a bit smaller bolt to go through the bracket hole.