Master cylinder for vehicle brake system

A master cylinder for vehicle brake systems, comprising:

• a housing having a first cavity defining a cylindrical sidewall surface, the first cavity defining an inner end and an outer end;
• a stem disposed in the first cavity and extending from the inner end of the first cavity in a cantilevered manner and defining a distal end;
• a plunger having at least a portion thereof moveably disposed in the first cavity and sealingly engaging the cylindrical sidewall of the cavity, the plunger having an inner end and an outer end and defining a second cavity, the second cavity having an open end at the inner end of the plunger, and wherein the stem is aligned with the open end of the second cavity;
• a fluid reservoir configured to contain brake fluid;
• a first fluid passageway extending from the reservoir through the stem and forming an opening at the distal end of the stem and fluidly connecting the reservoir to the second cavity;
• a second fluid passageway fluidly connecting the first cavity to an outlet opening in the housing;
• and wherein:
• the plunger is moveable relative to the stem between a first position wherein a gap is formed between the plunger and the stem, the gap fluidly interconnecting the first and second cavities, and a second position wherein the plunger sealingly engages the stem and substantially prevents fluid flow between the first and second cavities.