The cylinder has an annular groove (5) connected to the follow-up reservoir (14), and the bore (2) of the cylinder is stepped. A sleeve (4) made of synthetic material is fixed solely by the step (3) in the bore. A further bore (19) is located in the housing of the cylinder and runs from a follow-up reservoir connection (17) to the annular groove, and in which is located an element (20) axially fixing the sleeve. A floating piston (10) is formed in one piece with an intermediate piston (9) and forms the boundary of the first pressure chamber.
