A reservoir tank for a vehicle brake system has a tank body including upper and lower shells joined together along mating surfaces. A float and a fluid level sensor are mounted in a fluid level detecting chamber defined in the tank body. The float is fitted on a shaft of the fluid level sensor. A partition plate is fitted in the lower shell to restrict a flow of hydraulic fluid into and out of the fluid level detecting chamber. The partition plate is disposed near the top end of the shaft of the fluid level sensor to restrict the distance by which the float can move vertically. A filter, the fluid level sensor and the partition plate are all set in the lower shell. The filter and the partition plate having their top ends pressed against the bottom ends of partitioning walls of the upper shell. Thus, the filter and the partition wall are held in position in the tank body between the upper and lower shells.

A tank intended for an electrohydraulic braking system comprises, according to the present invention, a first chamber (7) for the supply of a primary hydraulic circuit of a master cylinder with brake fluid, a second chamber (9) for the supply of a secondary hydraulic circuit of the master cylinder (not shown) with brake fluid, a third chamber (11) for the supply of a hydraulic pump with brake fluid, and a fourth chamber (13), a measuring one, which accommodates a detection device, indicating when the brake-fluid level inside the tank is too low. The tank has a flow path for the interconnection of the first chamber (7), the second chamber (9) and the third chamber (11) when the hydraulic-fluid level is higher than a safety level, and for the fluid-tight separation of said chambers when the hydraulic-fluid level is lower than the safety level.

A hydraulic fluid reservoir and hydraulic pump combination has at least one hydraulic fluid port and includes a container with a hollow body having a top and a conduit having a bottom within the container and a top above the bottom. The conduit has an opening adjacent to the bottom of the conduit. The opening is spaced apart below the top of the container. A closure member is releasably, sealingly connected to the top of the conduit. Hydraulic fluid can be added to the container via the conduit up to the level of the opening of the conduit. Addition of further hydraulic fluid fills the conduit to the top thereof and the conduit overflows if additional hydraulic fluid is added after the top of the conduit is reached by the fluid. Preferably the container has a main interior chamber and a smaller chamber which is adjacent to one of the side walls of the container. The smaller chamber is has a bottom opening near the bottom of the smaller chamber which communicates with the main interior chamber. Hydraulic fluid enters the smaller chamber through the opening and reaches the level of hydraulic fluid in the main interior chamber. Bubbles in the hydraulic fluid within the main interior chamber are isolated from the smaller chamber and accordingly do not impair the reading of the hydraulic fluid level by a photo detector.

A hydraulic fluid reservoir apparatus for an automotive power steering system comprises a filter chamber, and a filter parallel to a vertical axis and dividing the filter chamber into an upstream region and a downstream region. The reservoir apparatus also includes a stagnant fluid well apart from the filter chamber, and a de-aeration zone overlying the filter chamber. A vent is provided between the upstream region and the de-aeration zone. Fluid recycled to the reservoir apparatus contains entrained gas. The filter separates the gas from the fluid within the upstream region, whereupon the gas is vented to the de-aeration zone and separates from the fluid circulated to the stagnant fluid well.