Trying to put on new brakes. The 18mm pivot nut is too short to reach the bolt through the fork and the 27mm one can't fit all the way in because there's some kind of lip deeper in the fork blocking it. Afraid if I take it to the LBS niggers they'll do something retarded like try to bore out the fork to make the long one fit. Wat do?
https://bike.shimano.com/en-EU/product/component/shimano/BR-R451.html