Abstract: The invention relates to a master cylinder with a pressure chamber formed in a housing of the master cylinder and a reservoir bore for accommodating a pressure fluid reservoir, a valve with a closing element being provided which due to a pressure difference prevailing between the pressure chamber and the pressure fluid reservoir can be moved into an opening position or a closing position, the valve in its opening position allowing a pressure fluid flow from the pressure fluid reservoir into the pressure chamber and throttling or preventing, in its closing position, a pressure fluid flow from the pressure chamber into the pressure fluid reservoir. Means are provided which maintain the closing body in its opening position when it is acted upon by a closing pressure difference during vacuum filling of the brake system.

Abstract: The invention relates to a master cylinder, in particular for a hydraulic brake system, with at least one pressure chamber formed in a housing of the master cylinder and at least one reservoir bore for accommodating a pressure fluid reservoir, a valve with a closing element being provided which due to a pressure difference prevailing between the pressure chamber and the pressure fluid reservoir can be moved into an opening position or a closing position, the valve in its opening position allowing a pressure fluid flow from the pressure fluid reservoir into the pressure chamber and throttling or preventing, in its closing position, a pressure fluid flow in the opposite direction to the pressure fluid flow from the pressure chamber into the pressure fluid reservoir.

Abstract: The present inventive relates to a master cylinder (1 ) with elastomeric central valves (20) which can be opened in opposition to a relatively high pressure in the pressure chambers (8 and 9) without damage. The sealing face (29) of the valve member (26) is in the form of a hollow cylinder protruding slightly from the broad head portion (24) of the valve pin (21). The valve member sealing face does not, as has been conventional practice, extend radially inwardly past the head portion (24) in the direction of the central bore (13) to avoid being drawn into the bore (13).