Originally Posted by Homebrew01

If your brakes do not have the flats for adjusting with a cone wrench, then 1 other way is to place the tip of a flat blade screwdriver on the spring near the center of the arm that is too far from the rim. The give the screwdriver a few taps with a hammer until the spring moves enough to center the brake arms. (Same as Andy's "punch" method above). I don't see any downside, other than possibly a tiny scratch on the spring.

New pads, a little tap, and you're good to go.