Success, but not what we thought
First, the unit that I broke is broke for sure. Nothing wrong with the replacable cam - the little crossbar behind and above the cam on the stationary base is what broke.I took my two sticky units completely apart and cleaned, but it made little or no difference. By swapping each piece from a brand new unit into an old sticky unit, I pinpointed the problem. Then I did the reverse: put the bad piece into the otherwize brand new unit and proved that it failed.The problem piece was the U-shaped spring (S-shaped on each side of the U). It took awhile, but I finally bent them back close enough to the operating shape and now they work again, almost as smoothly as the new unit.Somehow after a year or more of use these springs seem to have elongated such that the units would hardly open and close. This seems impossible, since it seems to me that these spring are only ever under compression load. It's this spring that makes it click open and click shut.Careful - I broke one of the springs by bending it too much and then straitening it again. Fortunately, I had an extra spring from the unit that is broken.I'm going to try writing to Spinlock. Maybe they'll send me a handful of spare springs......RickM...