Help! Installing Andersen No Sway WDH

The third challenge I have had was installing the brackets, as soon as I start tighten the bolts they slide forward, resulting in uneven distance from the RV coupler

When tightening the hardware, always hold the bolt steady with one wrench and turn the nut with another. This will prevent the bolt from acting like a roller sliding the bracket on the trailer frame.

Where ever possible, it is always a good practice to turn the nut, rather than the bolt accept when special purpose nuts are used that bite into the metal.

And do use a torque wrench to tighten all hardware to the specified torque. With out a torque wrench, what is "tight" is all suggestive according to one's physical strength.