How to Adjust the Mechanisms Inside a Toilet Tank
If you aren't mechanically inclined, the inside of a toilet tank can be daunting, but things are less mysterious once you understand what you see there. The mechanisms serve two functions: filling and flushing. The fill valve connects to the water supply and allows water into the tank. It keeps running until the float shuts it off. The flapper is part of the flush valve; it keeps the water in the tank until you lift it by flushing, and it reseats after flushing so the tank can refill. The adjustments needed to keep everything in working order aren't complicated.
The Fill Mechanism
1. Regulate the water level in the tank by adjusting the float. Unless your toilet has a pressure-assisted flush mechanism, it has either a ball float on the end of a rocker arm or a cup-style float fitted around the valve tube.
2. Screw the ball clockwise to shorten the arm if the water level is too low and counterclockwise to lengthen it if the level is too high. A longer rocker arm exerts more pressure on the fill valve and makes it close sooner. If your rocker arm has a bend in it, rotating the rod so the bend faces up is another way to lower the water level in the tank.
3. Squeeze the clip on a cup style float in order to adjust the length of the rod. Lengthen the rod to lower the water level in the tank and shorten the rod to raise it.
4. Look for an adjustment screw on the top of the fill valve. Not all valves have one, but if yours does, it allows you to fine-tune the operation of the valve. Turn it clockwise with a screwdriver to stop the valve from leaking when the tank is full.
The Flush Mechanism
1. Lengthen the chain holding the flush handle to the flapper if you feel tension in it when the flapper is down. A tight chain can make the toilet cycle on and off because it prevents the flapper from sealing the siphon hole, thus allowing water to leak into the bowl.
2. Shorten the chain if the toilet doesn't flush all the way. If the chain doesn't pull the flapper back far enough, the flapper falls prematurely and stops the flush.
3. Straighten the flapper if it is askew. It has two rubber ears that attach to the overflow tube -- pull them off, straighten the flapper and push them back on.
Things You Will Need
1. Most toilet leaks are caused by a defective or misaligned flapper. To keep the toilet in good working order, replace the flapper every few years.
2. If you have hard water, the fill valve can get blocked by mineral deposits, and your tank will take a long time to fill. You can flush the valve to remove these deposits by shutting off the water, removing the cap and turning the water on again slowly.