The steel chain slider screw and oval washer (items 12 and 27) sit on top of the swing arm and form a little well to colllect muck and moisture causing mine to go rusty. Maybe worth a look on your bike to see if they are also rusting up.   Before it rusted up completely and wasn't able to be removed from the swing arm (Lyn's observation when he saw my bike) I decided to replace top and bottom with new ones. They cost peanuts (was <£3 for 2x 12 and 2 x 27) but they ar