The bumper is installed using the factory bolts and large 9/16-inch Grade 8 bolts (not shown here) through the frame into the nut plates. Expedition One relieves their bumper for the body pinch welds. Remember the noise I was chasing on Project Trailrunner? It turned out to be the body hitting on a bumper that wasn’t clearanced here. We trimmed the body below the flare for more clearance.