Two-Piece Toilet
The Sterling two-piece toilet consists of a separate bowl and tank. The two pieces are separated by a rubber gasket and connected by three bolts and nuts. The tank sits on top of the back of the bowl. When the flush handle is pushed down, a rubber flapper in the bottom of the tank is lifted, letting the water in the tank rush onto the bowl. A float triggers a valve to open to allow the bowl to refill with water. Once the water reaches a certain level, the valve shuts off.
Cracked Tank
A cracked or broken toilet tank must be removed from the bowl for repair or replacement. Since the tank must be waterproof, it is difficult to repair a broken tank and not have it leak. Replacement tanks for Sterling two-piece toilets can be had for around $40 as of 2011. Total replacement of the tank may be a better solution in the long run.
Faulty Tank Seal
A bad seal between the bowl and the tank may make you think you have a cracked tank. Unfortunately, the job requires the removal of the toilet tank. Once the tank is removed, the mating surfaces on both the bowl and the tank should be cleaned so that the new gasket has a proper seal. The tank can then be installed in the reverse order of removal.
Tank Mechanics
A perceived tank problem may be caused by the inner workings of the tank. Water leakage may be caused by a faulty flapper in the bottom of the tank. If water gets past the flapper, the toilet valve will turn on to replenish the water lost. This will go on in an endless cycle until the flapper is replaced. A leak at the bottom of the tank may originate from a cracked water control valve or the gasket that seals the valve to the tank. The threads of the valve protrude through the bottom of the tank to provide a place for the water supply line to attach to. Replacement of any internal toilet tank parts can be accomplished without removing the tank from the bowl.
Tank Removal
Removing the tank may not be as hard a job as you may think. The first step is shutting off the water supply to the toilet. Most homes have a shut-off valve near the base of the toilet. If you cannot locate a shut-off valve, you will have to shut off the main water supply to the home. Once this is done, any water remaining in the tank must be removed. Flushing the toilet will evacuate most of the water. Any remaining water will have to be removed by absorbing it with a sponge or rag. The water supply line can then be removed from the underside of the tank. Once the three tank-retaining bolts are removed, the tank can be lifted straight up and off the bowl.