The pump seems to run a long time before cutting off. I have pressure and water for about 3 min then loose all water and pressure. After a while ,sometimes longer than others, the pump finally kicks on and I have water again. This repeats over and over. We found another leak. Fixed it then We changed the pressure switch. No help. Changed the pressure tank. Still we are getting burst of air and it starts another leak. What can cause the system to drain down and shut off for periods. The well , switch and pressure tank are about 100 yards from the house with a hydrant between at the stables.

The first thing I would have checked is the check/foot valve. If iut's bad the pump will pump to pressure and stop. Then the check/foot valve allows the pressure to bleed back down into the well and it starts all over again I don't know about the time lag but let's get your pump to hold pressure and if that doesn't cure it we'll look into it. Good luck, Tom

We have tried everything else. After he repairs this new leak, I will have he check it. Where do we find it and how will we know if its bad? If it is where can we find a new one? Most of what I have been getting has been at Lowe's.

Where do we find the check valve and how will we know if its bad? If it is where can we find a new one?
You symptoms would indicate the check valve's allowing the pressure to bleed back down into the well.
Check valves come in two flavors. A check valve mounted downstream from the pump or at the bottom of the well in the form of a foot valve, (see images) The up side to a faulty foot valve is the you can install a check valve topside and get the same results.
You can pick up a check valve at any Pump sales and installation company.
Good luck, Tom

We pulled the pump up and found no valve, just the pump on the end of the line. Hubby added a check valve, but we still have the same problem. When we turned the power back on the pump ran for about 3 min to fill the pressure tank that hangs in the top of the well and the lines then cut off. We went back to the house and ran the water. It ran for about 3-4 min then we lost pressure and water. It didn't kick back on. It comes on randomly and runs for just a couple min then off again. We fixed a leak, changed a pressure switch, changed a pressure tank ( we made a mistake and bought a smaller one than we already had). And added a check valve. And the water level seems fine. I am about to just jump in the well !

Hokie, before you take the leap, let's try this. Have someone turn on the water in the house while you and hubby are at the pressure tank. There should be a gauge there. Watch the gauge. This is what should happen. When water is used, pressure starts to drop. It goes down to some point, then you should hear the switch click, turning on the pump. Write that pressure down. Even with a faucet on, the pump should be able to slowly build up pressure to the point where you hear the switch click again. Write that pressure down. Those are you cutin/cutout pressures. You need to know those. All of this should only take 5 or 10 minutes.

This process will repeat itself over and over again. Watch until you see the gauge go down to around zero, which you seem to indicate it does by saying you lose pressure in the house. Did the switch click on? If it did, did the pump start pumping? You can generally tell that by feeling the wellpipe as it exits the well. When the pump is on, you can feel a gentle vibration in the pipe.

Now turn the faucet off. Once the pump pumps up to the cut off pressure, will the pressure hold steady? If not, then you have either a checkvalve problem or a leak between the pump and the house. Since the checkvalve is new, you would probably suspect a leak.

Get back to us with that info.

BTW, you said your pressure tank "hangs in the top of the well" and that you bought a smaller one than you had. What size do you have now?

There is no pressure gauge. When we turn the power back on it ruhs and builds pressure then cuts off. The problem is when we run the water and the pressure goes down the pump doesn't kick back on. But after awhile, like an hour or two I can go back to the faucet and there is water. Then we start all over again. We had a 15 gallon pressure tank that hung in the top of the well with just a pressure switch, but when we bought a new tank we got a 5 gallon. Didn't realize it was that big.

Your tank, to put it mildly, is WAY too small. I am assuming you are in a cold climate... thus the tank is in the well??

I would put a bladder tank (40 gallon) in the basement of the house. Put a checkvalve between the well and hydrant. Honestly, I don't really see the point of a 5 gallon pressure tank, in the well or anywhere else. So, you will go pump/well pipe/checkvalve/hydrant/basement/pressure tank. Switches are generally put alongside the pressure tank so you might need to look at some wiring issues there.

If you don't want to do all that, try to replace the 5 gallon tank with a 15 like you originally had, then look at the little pipe leading to the switch. That pipe can become clogged with crud and make the switch "buggy". And put on a pressure gauge!! That is a useful little device for diagnosing problems.