Centering screw working itself loose
I have dual-pivot brakes on my road bike, and the other day I started to hear the brake rubbing against the rim. I was towards the end of a group ride on a new route and didn't want to stop for fear of being dropped, so I kept going and the sound kept getting worse. When we finished and I saw that the brakes weren't even close to being centered, so I whipped out my multi tool, tightened the centering screw, and though the problem was solved.
The next night I was out riding and started to hear the pad rubbing again. I stopped to check the brakes and found that they were off center again. I checked the centering screw and it had worked itself loose, so I retightened it and was back on my way. It keeps happening, and now part of my pre-ride ritual is to check the brake alignment. I'm sure there's a way to fix this, but I just don't know how... Any help would be greatly appreciated.