In order to protect agricultural machinery from atmospheric corrosion during the nonworking period, it is possible to use bitumen primers (BP), which are compositions of petroleum bitumen with the addition of solvents and, possibly, other additives. The protective properties of compositions based on the bitumen primer "Orgkrovlya No. 1" diluted with white spirit with modifying additives on samples of 08kp steel were studied in the work. Accelerated corrosion tests in 0.5 M NaCl solution showed the following: dilution of BP with 40 wt. % white spirit when applied in one layer leads to a decrease in the protective efficiency to 75%, 67 wt. % - to 37%; the introduction of additives (5 wt.%) of P2 paraffin into the diluted BP with 40 wt. % white spirit increases its protective efficiency (Z) to 98%, KO-SZhK - up to 87%, Emulgin - up to 94%; When diluting BP with 67 wt.% white spirit, the maximum Z = 60% is provided by the addition of 1 wt.% drying oil +1 wt.% POOM. Accelerated tests in the G-4 heat and humidity chamber and the salt spray chamber showed the best results for BP coatings diluted with 40 wt.% white spirit and with the addition of 5 wt.% P2 paraffin. The highest values of protective efficiency in the G-4 heat and humidity chamber for BP diluted with 67 wt.% white spirit are provided by coatings with 2 wt.% drying oil (Z = 97%), 5 wt.% POOM (Z = 97%), 1 wt.% drying oil +1 wt.% POOM (Z = 96%). According to the 9-month results of full-scale bench tests of modified BP diluted with 40 wt.% white spirit, the best results are provided by the coating with the addition of 5 wt. % paraffin P2 and Emulgin. These 2 additives effectively protect steel in a concentrated solution (200 g/l) of mineral fertilizer borofoska.