Abstract: A hydraulic master cylinder formed by telescopically fastening together a pair of cylinder housings to form a cylinder. A piston in the cylinder is operative to transfer hydraulic fluid to a slave cylinder connected to the master cylinder. The pressure or power stroke of the piston is effected by exerting a pull on the piston by a pull cable attached to one side of the piston. A body, attached to one of the cylinder housing, provides a reservoir for hydraulic fluids. A cap on the reservoir closes a fluid filling opening. Expansion bellows in the reservoir accommodates changes in the fluid level in the reservoir as the piston is being reciprocated. The bellows is connected to the cap so as to be removed as a unit with the cap when the reservoir is being filled.