Steve--------I think you have been doing some fabulos work/design-----------your choice of materials and some methods are just not what I'd do--------but I do believe that your use of those tie rods for 4 link bars are over the line-they were developed for steering purpose/loads and not vehicle pushing /stopping rear end bars-they have a definite point of fracture at the end of the threads in the tubes and the lengthy ones you used put this point in a more fragal area

What airline do you fly for?????? I haven't seen Bob D since last century-----