A wellbore assembly is provided that can include a first motor housing assembly member and a second motor housing assembly member that can bend relative to the first motor housing assembly at a bend location. The assembly can also include a magnet positioned to emit a magnetic field. A sensor can be magnetically coupled with the magnet and positioned to detect the strength of the magnetic field emitted by the magnet. Based on the strength of the magnetic field detected by the sensor, the amount of bend or bend direction of the second motor housing assembly member relative to the first motor housing assembly member can be determined.
