The fuel pump on the early Daihatsu hijet had a diaphram that was replaceable. The newer fuel pump is a complete unit that does not even come apart. There are two types of fuel pumps. The first is mounted on the cylinder head of the Daihatsu Hijet and is driven by a pin that pushes the diaphram by the movement of the cam shaft. The second type of fuel pump is an electric fuel pump that is mounted inside the fuel tank. The water pump is mounted to the engine block and driven by the alternator belt. The Daihatsu S80 and S81 water pump look almost exactly the same as the Water Pump on the S82 and S83 Model. The S82 and S83 water pump has a larger diameter outlet for the radiator hose to connect and the neck of the shaft that the pulley mounts to is slightly longer.