Abstract: A rotary servo fluid pump and a rotary water pump for an internal combustion engine have respective drive shafts which are both drivingly coupled to the rotor of the servo fluid pump by splines, keys, dogs or by having non-circular section shaft portions engaged in complementary non-circular bores in the rotor of the servo fluid pump. Flow passages of the two pumps are preferably formed in a common pump casing part which can be directly mounted on the engine block with the flow passages in open communication with respective flow galleries in the engine block. The casing part can then serve as a mounting bracket for the pumps on the engine.