I pulled the wheel off and visually checked the brake-wear indicator. It is a good distance away from touching the disc. So that is definitely not the source of the squeak. When I hand-turned the wheel I did not hear the squeak. But that does not surprise me since, while driving, the squeak disappears when the weight of the car is shifted away from that wheel such as in a turn. The squeak also disappears when braking. Any other ideas?