Nylon locknuts differ from a standard hex nut in that they have a nylon insert secured within the nut. The nylon insert is located in a tapered section located at the back of the nut. When you install the nylon locknut onto a bolt or threaded stud, the nylon insert wraps around the threads and locks the nut in place. This gives a nylon locknut a distinct advantage over a lock washer when the bolt or threaded stud is subject to vibration, as the nylon locknut is unaffected by vibration.
Examine the nylon insert of the nylon locknut to ensure that the insert is not damaged.
Thread the nylon locknut onto the bolt or threaded stud and turn the nut clockwise with your hand until it no longer turns. This will be the point that the nylon insert contacts the top thread of the fastener.
Place the socket that matches the nylon locknut onto the 3/8-inch drive ratchet.
Slide the socket onto the nylon locknut and turn the handle of the ratchet clockwise to turn the nylon locknut onto the fastener. You will feel some resistance from the nylon locknut as you turn it onto the fastener. This is created by the nylon insert and is completely normal.
Continue turning the ratchet handle until the nylon locknut seats tightly against the surface of the material you are securing with the nut.
Inspect the nylon insert of the locknut to ensure that it is intact after installation.