From demolition derby to daily grind, there are all kinds of reasons to want a massively strong rear bumper. Functional considerations aside, a visually large bumper can make tailgaters think twice before getting too close and can protect your vehicle should they make the mistake of doing so. DIY bumpers like this don't require professional levels of skill or experience to fabricate; a welder, some basic fabrication tools and the know-how required to use them are the primary requirements.
Remove the stock bumper cover and unbolt the bumper from the supports. Hold a straight-edge up to the flanges on your bumper supports and mark the bumper support flanges on either side where they line up with the frame rails. Cut the support flanges in the vertical axis so that the sides of the flanges are flush with the frame rails.
Cut the heavy duty replacement bumper to about 6 inches wider than the vehicle. Have two assistants lift the bumper and align it. Take your time here and position the bumper exactly where you want it. If possible, use a couple of C-clamps to hold it in place. Otherwise, have your assistants hold the bumper while you crawl underneath and tack-weld the back of the bumper to the bottom of the support flanges.
Cut four 6-inch sections of 1 by 3 tubing. Hold two of them up on either side of the support flanges, sandwiching the supports and frame rail and butting the ends up against the back of the bumper. Tack-weld the fronts of the supports to the back of the bumper. Repeat for the other side. Drill two to three 1/2-inch holes all the way through two of the 1 by 3s, through the frame rails and out the other side of the opposing 1 by 3s. Temporarily install the bolts and washers.
Grind the tack welds off of the support flanges. At this point you could unbolt the bumper and remove it but don't . Leaving it bolted to the vehicle will prevent warpage while you cut and weld the license plate recess.
Mark the center of the bumper and center the license plate on that mark. Trace the sides of the license plate onto the bumper to leave two vertical lines. Measure 1/4-inch outward from these lines and mark two more vertical lines. Measure along the top and bottom of the bumper and scribe a line 1/2-inch from the front face of the bumper.
Cut the two outside vertical lines and the horizontal lines on the top and bottom with a thin cut-off wheel. After you've cut the vertical and horizontal lines, you'll be left with a C-shaped cut-out measuring roughly 12-1/2 inches wide and 6 inches high with tabs measuring 1/2-inch high. The license plate should fit into the recess in the bumper with 1/2-inch to spare on the sides.
Flip the cut-out piece over so that the part facing outward before now faces the inside of the bumper and insert it into the recess in the bumper. Weld the license plate recess onto the bumper along the top and the bottom of the bumper. Use a thick filler rod to create a thick bead to fill the weld channel.
Cut two pieces of steel plate measuring roughly 5-3/4 inches by 1/2-inch. Fit and weld them into the sides of the license plate recess to fill the gap between the face of the bumper and the flat of the license plate recess. Weld the fill plates to the recess panel and use a grinder to trim the edges where they protrude past the face of the bumper. Finish welding the fill plates onto the bumper face.
Cut end-plates for the bumper that measure 6 by 2 inches and tack-weld them to the ends of the bumper. Grind the excess away and weld all the way around the perimeter to secure the plates to the bumper. Remove the bumper and complete the welding job around the bumper supports. Grind your welds so that they're flush. Coat the bumper with a quality spray-on truck bed coating to seal and protect it.
Reinstall the bumper onto the truck. Slide the bumper supports onto the frame rails and install the bolts into the holes with washers on both the head and thread sides. They may or may not line up perfectly, so you might need to tap the bolts through with a hammer. Once the bolt heads are seated against the frame rails, place a drop of blue threadlocker onto the exposed threads before installing the nuts. Torque the nuts to about 100 ft.-lbs.
