Try tapping on the flat side of the stud or turning the adjustment. If it stuck hard don't mushroom the end by beating on it. Heat it up red hot from the shoe side and cool down with wet rag like the screws. You'll burn out the leather seals that go in the holding washers shown but they are normally junk anyway. You can either recut some leather or I like to use really large O rings that completely fill the space. they are like 3/16" in diameter and the studs OD.
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