1、First check whether the inlet & out let are correctly attached. If the out let is attached to suction section, reverse the order. Fill water from pump inlet right up to the foot valve,& then start the pump. If it doesn't lift water, you will have to check whether the foot valve is properly working. Whether there is a leak in the pipe from flange to foot valve, or air is drawn anywhere from pump to the pipe. Plug all these faults.
If still it doesn't work, check whether the pump itself is leak proof. For this one may have to replace the gaskets of the pump & screw them tight. If still it doesn't work, baffles inside the pump would have been wrongly arranged, in which case the position has to be corrected.
2、Checking water pumps in what way.because it has two meanings
when you go for buying- you need to check quality , brand, price, and its ok or not for your work.
when you use it- you need to check pump and its nozzle time -time for leakage and other problems that occures depending upon work of pump.
3、Look for leaks or a stain from a leak just below where the shaft comes out of the housing behind the pulley. Use a small mirror on an adjustable handle and a bright flashlight to get a good view. Many if not most water pump failures are of the shaft seal at that location. Also check around the perimeter of the water pump where it attaches to the engine block. A leak there would be the water pump gasket. Finally check the hose for leaks where it is clamped to the pump outlet headed to the radiator.