Abstract: Disclosed are a method of and a device for repairing a damaged upright spindle which is vertically movable, in a tubular attachment secured to a flange of a valve housing interconnecting two pipe sections, for raising and lowering a slider to block and unblock a flow through these sections. The attachment is removed and the damaged part of the spindle is cut off, preferably just above the housing flange, by a tool temporarily supported on that flange while the slider is left in the housing in one of its two limiting positions. Next, with the aid of a sleeve partly surrounding the remaining spindle stump, a replacement for the cut-off spindle part but of greater length is fitted onto the stump and is rigidly connected therewith. The attachment is then reconnected with the flange and is supplemented by an extension of a height exceeding that of the sleeve, the height of the extension substantially equaling the difference in length between the cut-off spindle part and its replacement.