Abstract: A device (10), and a method for forming such a device (10), for a fluid system for a vehicle, comprises first and second members (12, 13). The first member (12) is adapted for direct mounting on the chassis or engine of a vehicle (11); the second member (13) defines at least part of a leak tight fluid chamber (15) of the device (10). The first member (12) is of a thermoset material suitable for withstanding operating conditions and loads associated with direct mounting of the device (10) on the chassis or engine (11), and the second member (13) is of a thermoplastic material suitable for welding to ensure leaktightness of a fluid chamber (15). The second member (13) is interlocked with the first member (12) during moulding thereof.

Abstract: A vacuum pump comprises a casing body (11,12) having a cylinder liner (16) therein which defines a primary exhaust passage between the outer wall of the liner and the inner wall of the body. The exhaust passage includes restrictors (20,21), which permit the spaces (37,38) in the interior of the body to be used as silencer chambers.

Abstract: An apparatus and method for controlling an electrically driven vacuum pump (16) for a motor vehicle provides that below a predetermined level of vacuum (approaching atmospheric pressure) the pump (16) runs at a first speed, and above that level of vacuum the pump (16) runs at a lower speed or is stopped. Pump control is by switching of a single pressure switch (21) between two states, switching from the first state to the second state being accompanied by a time delay to ensure a minimum running period at the first speed.

Abstract: A reciprocating vacuum pump has a disc shaped piston (22, 122) having a peripheral elastomeric seal (52, 152) with oppositely directed, radially outwardly extending skirt portions (54,56); the piston is driven axially by a rod (34, 134) reciprocal in a lubricated bearing (42, 142) and a lubrication flowpath (50,48; 150,148) is defined between the bearing (42, 142) and the side of the piston (22, 122) opposite thereto.