Braking corrector dependent upon deceleration, for the braking system of a vehicle, comprising a body (10,11) defining a chamber (13), an inlet port (26) connected to the chamber (13) and intended to be connected to a source of fluid under pressure, an outlet port (42) connected to the chamber (13) and intended to be connected to the brakes of the vehicle, a mass (34) which is slideably mounted in the chamber (13) ' and which is sensitive to the deceleration of the vehicle, a valve means (44) capable of cooperating with the mass (34) so as to close the passage between the inlet port (26) and the outlet port (42) when the mass (34) moves under the effect of deceleration, a first spring means (38) normally urging the mass (34) towards a rest position opening the passage between the inlet port (26) and the outlet port (42), and a second spring means (20), characterised in that the second spring means (20) is stronger than the first spring means (38) and opposes the movement of the mass until a condition exists which is determined by a combination of the deceleration to which the mass is subjected and the pressure in the chamber.