I had a bolt pull through the frame on one side of my receiever hitch on my way to Canada pulling my boat one year. I did not notice it until I got to my destination, then noticed that one side of the receiver was hanging lower than the other side. Lucky for me it did not fail completely while driving. I went to a friendly local garage in CA, and had them fabricate a steel U shaped bracket that they drilled and bolted into the frame from the side. They then tack welded the new bolted bracket onto the frame of the hitch. It took them about an hour to do the work, and it only cost me $100 US to give me peace of mind for the next 5 years pulling my boat many more thounsands of miles.
The hitch was fine, it was the frame that rusted and allowed the bolt head to pull through the rusted frame member.