The steps of rocker panel replacement include removing the existing rocker panel, making the mounting surface of the panel smooth, and affixing the replacement rocker panel on it by welding. Wear protective gear and take someone's assistance when doing this task.
To remove the existing rocker panel, open the relevant door of the vehicle, take out the trim plate of the door sill using a Phillips screwdriver, and drill the spot welds securing the panel using an electric drill. Drill only via the top metal layer.
If the spot welds are stubborn, grind on them using a grinder to which a grinding wheel is affixed. Wear the required safety gear including safety goggles, gloves and ear plugs, and ensure that the grinder does not cut through the vehicle's body.
Once all the spot welds are drilled out, the rocker panel should be released. Pull the panel away to detach it.
After removing the existing rocker panel, use the grinder to remove any rough edges present on the panel's mounting surface. Position the replacement rocker panel on the surface, and affix it using a welding machine and electrodes.
Have two people assist you in holding the replacement panel in place while welding. Wear a welding hood, gloves and safety glasses when welding, and ask your assistants to do the same. Alternatively, have the replacement panel welded by a professional welder.