Brake Disc service and repair need a disc resurfacing kit (J 41013) and wheel hub resurfacing kit (J 42450-A). The brake system team does not need to refinish disc brake discs during normal vehicle maintenance. Technicians should avoid refurbishing new discs for things such as brake noise, uneven or premature pad wear, surface corrosion, minor scoring, or to fix high lateral runout (LRO). Workers must inspect the disc thickness first to make sure refinishing does not decrease the minimum approved thickness. When thickness issues, significant corrosion, fractures, blue stains, or deep scoring show up the parts call for a refinishing process. Start by removing all dirt and rust from the hub/axle flange and Brake Disc surfaces using the wheel hub resurfacing kit part j 42450-a and the disc resurfacing kit part j 41013. Make sure the brake mating surfaces are free from particles before doing the disc installation onto the brake lathe. Please let the lathe run while you introduce cutting tools to touch both disc friction areas and check the mark to make sure the parts attach correctly. Install the disc onto the machine like indicated by the lathe manufacturer. Sand using defined methods before measuring the disc thickness at regular intervals. Replace the disc and start new rebuilding work once thickness falls below specified limits. Replacing the disc is necessary if its thickness is above the specified limit. Set the device to its recommended speed setting and sand the disc surfaces with either 120 grit aluminum oxide sandpaper on the non-directional tool or 150 grit sandpaper on the sanding block. Wipe friction surfaces with denatured alcohol or an approved brake cleaner. After taking the disc out of the lathe use measurement tools to check if the entire braking system performs properly for specific tolerances.