Toilet tank was leaking from attaching bolt holes and under tank. I replaced all mechanisms with new inside the tank and new attaching hardware. The tank still leaks from the bolt hole at back of tank? This is a three bolt tank to bowl. How can I stop this leaking from the bolt holes? Thanks.
Since it should not leak if the washers were assembled properly, the two things that come to mind are, that the tank is cracked at that bolt, or you installed metal washers between the head of the bolt and the rubber washer inside the tank.