A method of manufacturing a valve rotor with a wear-resistant, low-friction surface, wherein a disk having angled edges and a shape which correspond with the surface of the rotor is formed from a sheet of polytetrafluoroethylene (PTFE). The disk is placed at the bottom of a mold cavity, and a plastic material is injected in the mold. The plastic fills the mold cavity surrounding and covering the angled edges of the disk. Once hardened, the plastic is locked together with the angled edges of the PTFE disk. In a preferred embodiment, a method of manufacturing a water treatment valve rotor with a PTFE rotating surface is shown.