The operating experience of hoist units for underground and overhaul of wells in the fields of the Bashneft oil campaign and their technical maintenance at the departments of technological transport have shown that, upon expiration of their service life, they are written off as scrap metal. For the reliability of sufficient residual safety margin and maintainability of hoisting units by the end of service life, certain manufacturers examined each unit separately by type of work when performing scheduled preventive maintenance schedules for the period from 2013 to 2018 in a specialized workshop of the oil company Bashneft. Analysis of the repair of individual parts and assemblies during the implementation of the schedule of preventive repair shows that the hoisting units for the most part have a large margin of safety. It can be confirmed the reliability of the large residual margin of safety and maintainability of the masts of the hoisting units that have worked out their factory life. The advanced technologies in the field of heat treatment and spraying with carbide powders of the mating working surfaces of the parts (in the design of the winch braking mechanism) of the hoisting unit have been changed. Particular attention is paid to mast construction elements that are subject to cyclic loads, corrosive effects (the mast post area at the wellhead) and even shock loads. Based on the results of an in-depth analysis of wear and its causes, using non-destructive testing technologies for parts and assemblies, appropriate technologies for restoration of unit parts are selected, such as chemical-thermal heat treatment (nitriding) in electric shaft furnaces, gas-thermal spraying with hard-alloy wear-resistant powders.