Kargo Master Single Drop Down Ladder Rack E-Series/GM (40953) - Manual (Page 9)

Attach ladder pan stiffener, in the closed position, using 5/16”x5/8” bolts with lock and flat washers. Confirm that
distance between passenger side feet and driver side feet are still EXACTLY the same. Now you can tighten the gutter
clamps for the front bow assembly. The installation is complete.