The Citroën SM has four powered discs brake system, triggered by a DS like pedal gear using two independant circuits: front/rear with an important reserve of energy. The front break circuit is fed by an accumulator linked to the main pressure reserve. The rear break circuit is directly connected to the rear suspension system. An hydraulic fluid corrector triggered by the rear suspension balances the effort from two distributing pistons according to the variation of the load on the rear axle. This improves the braking ability whatever the load variations and allows the best grip and the best roadholding. The hand brake acts on the two front wheels with pads and callipers that are independant from the main braking system.