What Causes Lug Nuts to Break?
1 Answers
Tire lug nuts will not break when tightened with a torque wrench. Broken lug nuts are typically caused by previous over-tightening with an impact wrench. To improve efficiency, repair shops often set the impact wrench to maximum torque, which gradually stretches the lug nuts and eventually leads to breakage. The following steps outline how to handle a broken lug nut: 1. First, clean the surface of the broken lug nut and use a center punch to mark the center of the broken surface. Then, use a drill with a 6-8mm bit to drill a hole at the marked center. Once the hole is drilled through, replace the small bit with a 16mm bit to further enlarge and penetrate the hole. 2. Use a welding rod with a diameter of 3.2mm or less to weld from the inside out within the drilled hole of the broken lug nut. Start welding at about half the length of the broken lug nut. Continue welding until the upper surface of the broken lug nut is reached, then build up a 14-16mm diameter, 8-10mm high cylinder. 3. Use a hammer to strike the end of the welded cylinder, causing vibrations along the axial direction of the broken lug nut. 4. When a small amount of rust is observed leaking from the fracture after striking, place an M18 nut over the welded cylinder and weld them together. 5. After welding, let it cool slightly, then while still warm, use a socket wrench on the nut to twist it back and forth. You can also lightly tap the end of the nut with a small hammer while twisting to help remove the broken lug nut. Once removed, use an appropriate tap to clean the threads inside the mounting hole to remove any rust or debris.
