Rebuilt brake calipers and headlights go out / high beams

It's usual for the low beam filament/light to be turned off when the high beams are turned on. It may be as simple as the high beam filaments being burned out. It's also possible that there's a blown fuse or malfunctioning relay or other component in the high beam circuit. It would be relatively rare for both high beam filaments to burn out at the same time, though quite often they do burn out at around the same time since they're both exposed to the same use and abuse and often both get replaced together.