[BRENT in 10-uh-C]

My "approved method" for the easiest way to install them is to place them inside of a large socket that supports the cap only around the perimeter. Use a ball-pein hammer to tap into the concaved section to increase the crown (-which decreases the circumference of the outside of the cap). Once the cap circumference has been decreased, the cap will fall right into the counterbore. A couple of taps on the crown of the cap will flatten the convex and increase the circumference size wedging it into the counterbore of the A-2040 Brake Adjusting Bracket.

FWIW, the finished counterbore size of the A-2040 Bracket is 1.215"-1.218 according to the factory print.