The wear on the inner surface and bore of the distribution plate stems from the same cause as the wear on the rotor: friction between the two components resulting from the rotor's axial movement.
The repair method for the distribution plate should be determined based on the extent of wear on its flat surface. Minor scratches can be remedied by lapping on a precision surface plate, whereas more severe wear requires machining on a lathe to restore flatness. The depth of the cut should be just enough to remove the damage-minimizing material removal is crucial to avoid compromising the plate's structural integrity or causing deformation. After machining, the non-parallelism between the two flat surfaces and the non-perpendicularity between the flat surface and the bore's centerline must not exceed 0.01 mm.