Doh!! I knew that. Or used to. As many times as I have fooled with these things -- adjusted, repaired, replaced -- I should have got this straight. Been riding on discs too long, memory fades. Also the age thing . . .
knocking off that block would have been a MAJOR PITA, and likely not possible. Would have led to a whole new backing plate in a big hurry. So... Um, no, gonna bust my britches getting this stubborn SOB lose, or know the reason why not.
i'm Still looking for the picture of the fire-hammer . . .