About four months ago we replaced our clawfoot tub faucet because the diverter was no longer diverting water. Now we have a new problem, the hot and cold water knobs will not stay in place. They stay closed just fine, but once opened, even just a little, they will continue to open on their own to full open. It seems that with the very course threads the water pressure is able to push on the steam and open up the valve. I have tried closing down the supply valves to the point where the shower is just barely getting enough water, but the knobs still turn on their own. Has anyone had this problem? Is there a fix?