Stopping leaks and sweating.
A toilet tank sweats when cold water in it causes warm, humid air to condense on its surface. To tell whether moisture dripping from a tank is due to a leak or to sweating, put food coloring in the tank. An hour later, touch white tissue to the bolt tips under the tank. If the tissue colors, there’s a leak; if not, the tank is sweating.
Leaks in a wall-mounted tank Leaks may occur at either end of the pipe leading from tank to bowl. With a spud wrench or large pipe wrench, unscrew the slip nuts at both ends. Wrap the pipe threads with self-forming packing; retighten the nuts. Leaks in a bowl-mounted tank To stop a leak around a tank bolt, drain the tank. Have a helper secure the bolt with a screwdriver; then tighten the nut under the bowl rim with a socket wrench. Don’t overtighten; the tank may crack. If leaking continues, remove the bolts and replace the washers.
If the tank leaks at the flush valve, drain the tank; use an adjustable wrench to unscrew the nut joiningthe ball-cock shaft to the water-inlet pipe . Remove the tank bolts, lift the tank off the bowl, and lay it on its back. Unscrew the locknut from the valve-seat shaft; pull the valve seat into the tank. Replace the washer at the top of the shaft and the conical spud washer that covers its base. Reassemble the tank.
Preventing tank sweating
Line the inside of the tank with a ready-made liner, or cut 1/2-inchthick insulating foam rubber to fit. Drain the tank and sponge it thy. Cut a hole in the front panel of the liner for the flush-handle bracket; make sure the liner doesn’t block any moving parts. Glue the insulation in place with rubber cement or silicone glue; wait 24 hours to refill the tank.