My pump started humming today, no water. It cuts on, hums then cuts off which made the casing hot so I unplugged it. I am picking up a new (same kind, sears 3/4 hp shallow well jet pump) tomorrow. I have never installed one. My set up is a pump about 300' down that pumps water into a huge holding tank then to the pump I am replacing (which pumps the water & air to the pressure tank) then to a pressure tank then to the house. When (and if) I get the pump off, am I suppose to let the pressure out of the pressure tank before I take the pump off? What kind of thread sealer do I use when I reinstall? The only well service I found wanted $375.00 to install a $300.00 pump that has 2 pipes on it. Thanks in advance for any help with this, it is appreciated.