Very timely, good information. There are other issues as well regarding brackets that only attach at left and right frames. You observed the spider cracks around the bolts. In another brand, the brackets were very thick but still caused metal fatigue that allowed a portion of the box frame to be ripped off. As a result, the mfg requires a horizontal ‘spreader‘ that connects the left and right bracket. The spreader bolts to the towbar and prevents it from easily collapsing for storage. (search JLwranglerforums for more)
Demco makes a baseplate with integrated ‘spreader’ which is what I installed. The through bolts would benefit from the fix you describe to spread the force by using a large washer under nut and bolt head. Mine does not have the inside tube that would prevent ‘frame crush’.
I used a paint pen to ‘index’ the position of nut and bolt head against the frame. That way at least I can take a look with a mirror and spot any movement.
Another issue on a 1500 mile trip to the mountains in September was my new towbar‘s triple lug swivels becoming really loose, floppy loose. Whlle the center connection became so tight I could not collapse the legs. A call to the mfg told me to simply wash and rinse the connections with soap and water to remove road grime on the overly tight connection while ‘slightly’ tightening the swivels on the triple lugs. (I was not comfortable with this as it is obvious the lugs could become warped or the bolt stretched. I spoke with the mfg and wound up getting it rebuilt even though it only had 2000 miles and 4 months on it). This model has teflon washers that provide a tight swivel without requiring lubrication.
You are right on target with these warnings, we can all get complacent. I looked at the mfg ratings and kept well under those limits. But I began to question the ‘authorities‘ and learn a lot about them.
There are forces on our vehicles which are mostly box frames and these tow forces are not completely understood by tow equipment mfgs.
It seems as if the tow equipment mfgs do not think about vehicle frame loading forces. At the same time, the vehicle OEMs may say the vehicle may be flat towed but do not specify detailed connection procedures for the tow equipment mfgs.
Thanks