This is a quick guide on replacing a faulty joystick on an N64. If you have a controller with a wobbly joystick, this is the way to resolve your issue.

This can also be considered a mod if you are upgrading the joystick to a redesigned replacement. Upgrading is recommended because the Nintendo 64 has a poorly designed joystick that is prone to breaking and because the redesigned joystick has better control.