A hydraulic clutch clutch is used in some cars, e.g. GAZ Wolga, it differs from a mechanical decoupler only in that, that the lever system, rollers and rods is replaced by a hydraulic system. The hydraulic clutch decoupler makes it possible to reduce the pressure on the clutch pedal to a minimum and facilitates the constructional solution.
The function of the hydraulic decoupler is as follows: The clutch pedal is connected to a small diameter piston located in the pump cylinder. The cylinder is filled with fluid (hydrolem) topped up from the tank and connected with a hose (tube) with a second larger diameter cylinder, in which the piston connected to the lever also moves, disengaging the clutch. Pressing the clutch pedal causes the piston to move, which covers the opening of the fluid inlet from the tank in the pump cylinder and, with further movement, forces the fluid into the cylinder located on the clutch housing, which moves the piston connected to the clutch release lever in the last cylinder. The clutch is disengaged.