greygoos wrote:Is there an adjustment nut inside the hitch?
There is no adjustment on this older style. The pivot arm on the top simply swings the locking collar forward to wrap around the ball and then the arm drops down with two teeth that drop into slots to keep the release mechanism from operating until it is lifted again. This type also has a hole to install a lock to keep the pivot arm from being accidentally disengaged very similar to the new style couplers.