Hi there, I have a 6" Everbilt frost free sillcock with vacuum breaker and recently attached an irrigation system and timer valve. When the timer valve closes, the sillcock begins a repetitive banging noise about 3 times a second. During each bang, a small amount of water squirts out of a small hole in the sillcock shaft. I am guessing what is happening is when the valve closes abruptly, the water pressure on either side of the sillcock seal washer equalizes and the spring pushes the valve closed. This allows water in behind the washer into the shaft and vents the pressure (squirt). This creates an imbalance and the sillcock washer is pushed back by the house pressure again, filling the whole valve, the spring pushes back and it happens again .... Bang bang bang. Possible solutions? I thought of cutting the spring to reduce the force, and filling the hollow shaft with epoxy to stop the squirt... Thoughts?