Toto TANK TO BOWL GASKET 9BU024E

The 9BU024E is sized for a 3 inch flush valve, so it only fits Toto models built with the 3 inch valve. The way to check without guessing is to lift the tank lid and look at the flush valve opening in the bottom of the tank: a 3 inch valve is noticeably wider than the older 2 inch style, and a 2 inch gasket dropped onto a 3 inch valve will not seal at all. Match the valve size, not the model year.

If the drip is coming from the seam where the tank meets the bowl, the tank to bowl gasket is the usual culprit, and on a Toto with a 3 inch flush valve the 9BU024E is that seal. Two things worth ruling out first: leaks from the bolt heads themselves point at the tank bolt washers rather than the gasket, and a leak that only appears at the base of the bowl is the closet flange wax seal, a different part entirely. A gasket that has gone hard or taken a permanent set will keep weeping no matter how much you tighten the bolts, so replacement is the fix, not more torque.

You get the gasket only, one piece per pack. Tank bolts, brass washers, rubber bolt washers and nuts are not part of it. That matters on a repair call, because the bolts that come out of a tank that has been leaking are often corroded, and reusing them on a fresh gasket is how you end up back at the same job. Plan on a tank bolt set alongside the gasket if you're servicing an older fixture.

Yes, it's a Toto factory replacement part, MPN 9BU024E. For property managers and maintenance crews running Toto fixtures across a building, using the manufacturer's own gasket keeps the seal geometry matched to the tank and flush valve it was molded for, which is where universal aftermarket gaskets tend to cause trouble on Toto's 3 inch valves.

Replace it. Once a tank to bowl gasket has been compressed and then released, it rarely reseats cleanly, and the second job is always harder than doing it the first time. Any time the tank comes off a Toto with a 3 inch flush valve, put a new 9BU024E in while it's apart. It's a single piece and the tank is already off the bowl.

One gasket per pack. If you're stocking a truck or a maintenance closet for a building with a run of Toto two-piece toilets, order per fixture rather than expecting a multi-pack.