Abstract: A master cylinder reservoir for use in a tractor hydraulic braking system has a pair of separate compartments, each adapted for connection to a respective one of a plurality of pressure cylinders. The compartments are interconnected by a flexible connector such as a convoluted tube, and the reservoir is advantageously made in a single piece by blow molding enabling the relative positions of the cylinders to vary so that the reservoir can be readily mounted by spigots engaging bores in the cylinders. The reservoir also has a flanged rigid tubular connection component molded into it during the reservoir molding operation, the material of the reservoir closely surrounding opposed surfaces of a flange of the component to resist longitudinal withdrawal of the component.

Abstract: A helical thrust bearing (14) is arranged between two rotatable cam components (12 and 13) of a brake actuator. The cam component (13) is turned first while the brake slack is being taken up and the brake-applying force is relatively low, the reaction to such force being transmitted to the body (10) at a plain axial thrust bearing (17,18). Only the cam component (12) is turned when the brake is actually being applied with the relatively high brake force which is transmitted to a thrust member (15) at a roller axial thrust bearing (16). This enables the pneumatic force motor or the prime mover to be used more efficiently. Also a greater angular displacement at the helical thrust bearing (14) is obtained for a given angular displacement of the cam components (12 and 13) relative to the body (10).In a modification, the plain thrust bearing (17,18) is replaced by another helical thrust bearing.