This section will show the working of the hydraulic savety valve as used in the Citroën ID/DS cars.

hydraulic savety valve The savety valve (distribution block); preserves hydraulic pressure for the brakes in case of a leak in the hydraulic system. It does that by blocking the hydraulic flow to the suspension in case the pressure is dropping (below 90 kg/cm2). The switch (present on the ID cars) is connected to the red STOP lamp on the dashboard indicates there is low pressure in the system. It switches around 70 kg/cm2. For the DS the electric switch is located below the brake pedal and the hole for the electric switch is blocked with a plug. On the right of the valve, the return hose is connected, to return leaked fluid back to the main reservoir.
Savety valve internals During the years mechanical changes have been made to this valve, however the basic principle is the same. The valve displayed is used after 1967 in the ID, Dspecial/Dsuper.

Thanks to Dick Tjalkens for the show model of the savety valve.