The pin that holds the retaining clip on my Shimano R550SPD-SL pedal has somehow come out of its socket, well, not completely. But the result is that it doesn't clip the cleat properly, and it does so very, very loosely. I can squeeze it back into place with pliers, but invariably it comes out again.


This isn't my pic, just one I found with the same issue. You can see the pin coming out. On my 105's this pin is replaced by a threaded bolt, which is a much better solution.

Any ideas on how to keep that pin from coming out?