Originally Posted by photostudent

Actually my LBS ordered me a new Shimano return spring a couple months ago. You just need someone who knows how to read their parts book. If there is no physical damage dried prawl pivets are normally the problem as noted in several replies here. As a "flipper" I get a lot of practice working on these. Just applying a penetrant, (PB is the best), rarely works. Penetrant and rocking the prawls with a pointed tool will eventually free them. It has never failed for me. On some models you may need to break away a piece of the plastic cover to get to the prawls. A small Allen wrench works well as the pointed tool. The same procedure works on "Rapid Fire" shifters.