Hydraulic cilinder, especially trow-out cilinder for hydraulic clutch actuation in vehicles

The hydraulic cylinder has a housing with a cylinder wall for receiving a longitudinally moveable piston. The piston and the cylinder wall define a pressure chamber. The piston has a surface for a sealing element which cooperates with the piston surface in an operating position of the piston to seal the pressure chamber. In the start position of the piston, the pressure chamber is connected to a back lash region by means of equalizing grooves. The cylindrical wall is profiled recesses particularly at the lower end. These recesses each have an upper limiting surface which rises to the grooves when the cylinder is in place.