The Lock Nut is used to secure and lock parts in place. This is a gold, metal, individually sold part which can be installed with a wrench set, and socket set, and attaches onto various locations on a variety of equipment. If broken, damaged or worn, the part may be loose, and there may also be physical damage to the nut, at which time it...Read more should be replaced. Refer to your make, model and diagrams to ensure this is the correct part.