The impact of enforced oscillations of the free surface of fuel in the car tank on the stability area of a closed digital brake force distribution system is considered. The object of the study is the process of stabilized movement of the tanker during the emergency braking. The subject of the study is a large tanker with a gross weight (3-3.5) *104 kg, equipped with a tank with a volume of (17-20) m3 and a system of direction stability. The goal of the work is investigation of the impact of transported fuel fluctuations on the stability of the refueling vehicle during the emergency braking and introducing of methods for selecting values of variable parameters of the electronic brake force distribution system to minimize it. Conclusion. Considering the oscillations of the free surface of the liquid in the mathematical model of disturbed movement of a closed system of stability significantly reduces the stability area of the system in the low frequency range due to the loop, the size and position of which depend on the filling level of the tank. Need to choose an envelope loop that according to different levels of tank filling.