The machine 'knows' how much water is inside because there is a pressure switch (two usually) - as the water level rises the pressure in the switch unit increases and then when it is at the right level it switches the solenoid (electric tap) off. It sounds to me that in your brush replacement activities you have disturbed the connections to the pressure switch. If you get the back off it again so you can see what is where you can probably fix it. Look for a round metal/plastic unit about the size of a crumpet (!). As I say there will be two and they will be high up at the side of the machine probably. they should obviously have electrical connections to them which may have been disturbed - check that. Also and very importantly there will be a narrow plastic tube running from low down on the drum, along and then up to the switch. As the water in the drum rises, water trapped in the tube also rises and increases air pressure in the round bit. Check the tubes are both connected securely and not kinked or punctured at all. If there is nothing obvious that you can fix then you can pull the tube off the drum (assuming there's no water in it) and let out any water in it. If you blow down the tube you should hear a click from the round bit - that's the switch working. Hope that helps a bit.
Richard
January 2009
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