Abstract: In a servo booster in which the rear part of the valve body is slidably guided in a guide in the rear end of the booster housing, the rear part and the guide have non-round cross-sections to prevent the valve body from turning relative to the housing. This is of particular benefit when a tie extends through the movable wall for transmitting braking reaction forces. Such a tie has to be sealed to the movable wall by a suitable seal, and any turning of the movable wall might damage the seal.The interior of the valve body is of circular cross-section so that, due to the non-round external shape, a radially thickened portion of the valve body is formed to carry a fluid conduit.

Abstract: In order to reduce the distortion of a servo booster housing in use the booster is provided with one or more ties which extend through the movable wall for transmitting reaction forces directly from the master cylinder housing to the vehicle bulkhead between which the booster is mounted. This enables a housing of lighter weight, such as a plastics housing, to be employed, and an overall saving in weight may be achieved. The front or rear housing wall, or both, is provided with a sleeve which encases part of the tie within the housing. The sleeve may perform various functions: it may be keyed to the tie to resist turning of the tie, it may be arranged to support a rolling diaphragm sealing the tie to the movable wall, and its free end may locate a peripheral bead on the rolling diaphragm.

Abstract: In order to reduce the distortion of a servo booster bousing in use the booster is provided with one or more ties which extend through the movable wall for transmitting reaction forces directly from the master cylinder housing to the vehicle bulkhead. This enables a housing of lighter weight to be employed, and an overall saving in weight to be achieved. A diaphragm support plate of the movable wall is sealed to the tie by a rolling diaphragm, and the support plate is provided with a tubular extension co-axial with the tie.

Abstract: A disc brake having a caliper member which straddles a minor portion of the periphery of a rotatable disc and which is displaceable with respect to a fixed torque-taking member of the brake for applying friction elements to opposite sides of the disc. The caliper member is slidably mounted on the torque member by means of a pin secured to one of the members and slidable in a recess in the other of the members. The torque member also slidably carries the friction elements and restrains the elements from movement radially of the disc. In order to prevent the caliper member from pivoting about the axis of the pin, the caliper member is held by at least one of the friction elements, this being effected by an interengaging projection and recess, the recess opening in a generally radial direction relative to the axis of the pin.

Abstract: A reservoir of synthetic plastics material for a master cylinder is constructed from a base and a lid which are permanently connected together at their mating faces, for example by welding, along a join line which lies in a single plane. A partition is upstanding from the base and a passage defined by a wall and including a portion of the lid provides limited communication between chambers on opposite sides of the partition. At least one end of the passage lies outside at least one edge of the lid and the join line passes through the partition.