When tightening lock nuts with recessed nylon, you do not need to tighten
very much. These type of lock nuts will not loosen due to vibration so you
only need to make them a little snug. Tightening these too much will cause
problems. These are the kind of nuts that are on the underside of pop
bumpers that secure the ring and rod assembly. Overtightening these will
cause the threads on the rod to snap off--and then you'll have to completely
disassemble the bumper to replace the broken ring and rod assembly!