Modifying brackets for body lifts will vary depending on how the bracket attaches to the vehicle and the shape of the bracket. Brackets that attach to the underside of the frame will be harder to modify than brackets that attach to the side or front of the frame, in general. For example a dual-tube front bumper such as the SmittyBilt bumper on the '84-'88/9 4Runner/pickup is easy to modify for a body lift, since it mounts to the front of the frame, using 2 vertically-aligned bolts. Take a piece of flat steel bar, drill two holes to fit the bracket then slide up a distance to match the lift and drill 2 new holes. On shorter lifts, it may not be required to lift the bumper, or rather it may not be worth the effort to raise the bumper and it may look OK as-is. For custom applications, it may be possible for 4Crawler Offroad to design bracket extensions or modify brackets, please forward photos/sketches/dimensions of the part in questions for a quote. Pictured below are some examples of modifying bumper and brush guard brackets for body lifted applications:
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