My Coleman Extreme 48qt mash tun is leaking from the seal by the ball valve. It looks to me like the seal is now getting pushed in a bit causing a void that liquid can get through. A few times ago it was a small drip, but now it is a substantially higher volume after I tried to fix it. Anyone had this problem? Any thoughts on a solution? I was thinking maybe a new seal that would fit the inside factory seal, or maybe a seal with a stainless washer on top holding it against the tun wall.