Abstract: The invention relates to a process and an apparatus for repairing worn labyrinth seal flanges. The seal flanges are repaired by spin-forming them to increase their radial height to at least equal that of an unworn labyrinth seal. A tool for carrying out the process has a pair of parallel rollers displaced a constant distance which is advanced radially inwardly over the seal flange so as to deform the sides and cause the material to creep in a radially outward direction to increase the height of the flange. The flange may be ground to remove any residual defects caused by the spin-forming operation.