There's some crap in the wedge pin springs and the general area, Here are some good pics of a rubber mud flap protection for that area.Spray pins with penetrating oil and tap with hammer. If that doesn't work try heating them with a torch and tapping with larger hammer. If you have to beat it lot use a piece of softer metal between the hammer and pins to keep from mushrooming them over. Sometimes several heating and cooling cycles may be required to loosen stuck parts.