Originally Posted by Charles Wahl

I don't know (without trying it) why the method I suggested wouldn't work: put the dropout side of the pivot (3563L, 3561, pivot body, together with the spring (3885), wind the spring up from the outside, hold the wound end of the spring in the slot at the edge of the pivot hole deftly with a blade, and insert the pivot bolt, engaging the keyhole in 3563L and trapping the end of the spring in the slot at the same time. Then 3561 is just a sleeve, and its keyhole isn't used.