Abstract: The die-casting mold and the die-cast brake master cylinder housing comprise an axial master cylinder piston bore and a compensating bore, whose latter axis extends parallel to the axis of the master cylinder piston bore. The compensating bore has one end terminating in a compensating reservoir port oriented transversely relative to the housing's longitudinal axis and its other end terminating in a sealing chamber that is formed by an extension of the master cylinder piston bore. To render the casting process for manufacturing a die-cast brake master cylinder housing simpler, the mold comprises a core for the compensating bore whose longitudinal cross-sections containing the longitudinal axis are of conical construction, with the narrowest point being adjacent to the compensating reservoir port and whose cross-sections extending vertically to the longitudinal axis are of substantially reniform construction, while the concave sides of the cross-sections are close to the master cylinder piston bore.