American Standard Flapper and Chain with Float for 2-Inch Flush Valves - AMS-7381129-200

The 7381129-200 flapper and chain assembly is built for American Standard tanks with a 2-inch flush valve, so the first thing to check is the valve seat in your tank, not the toilet's model year. Measure the opening the flapper seals against: a 2-inch seat takes this part, and a 3-inch seat needs a 3-inch flapper instead. American Standard publishes repair part information by toilet model, and matching against that is the reliable way to confirm before you order.

A tank that refills on its own with nobody touching the handle is almost always the flapper, not the fill valve. The rubber takes a set, the seal against the valve seat breaks, and water bleeds into the bowl until the level drops enough to trigger the fill. On a 2-inch American Standard flush valve, the 7381129-200 flapper and chain with float is the replacement. If instead water is spilling into the overflow tube, that is a fill valve or float adjustment problem and this part will not fix it.

The float on the flapper controls how long the flapper stays open on a flush. Sliding it down the chain lets the flapper drop sooner, cutting the water used per flush; sliding it up holds it open longer for a fuller flush. That adjustment is why this style of flapper is worth keeping in a maintenance stock: on a fleet of toilets you can trim water use without touching the fill valve. Set the chain with about a half link of slack so the flapper seats fully.

Sometimes it seals, often it does not sit right. American Standard flush valves use their own ear spacing and seat profile, and a generic 2-inch flapper that clips on can still leak or hang up because the geometry is slightly off. Ordering the American Standard 7381129-200 assembly gets the flapper, chain and float matched to the valve it was made for, which is the difference between one trip and three.

No tools. Shut the supply stop, flush to drain the tank, unclip the flapper ears from the pegs on the flush valve, unhook the chain from the trip lever, and reverse it with the new one. Five minutes per fixture, which is what makes this a practical part to buy in quantity for a building where several toilets are running.