American Standard Toilet Fill Valve: Which Part Fits?

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Quick answer from a licensed plumber: American Standard names one fill valve for its Cadet, VorMax and Champion toilets: the Universal Toilet Water Fill Valve, part number 7381125-400.0070A (its store calls it the “Fill Valve Universal 400A-Repair Part”). Before you buy it, run American Standard’s overnight leak test: a level that does not drop means the fill valve; a level that drops means the flapper or flush valve, and those parts do change by line. Then flush the valve with a cup of water; replace it only if it still runs.

The part: American Standard Toilet Fill Valve, Universal 400A Tank Repair Part (Amazon-sold on September 24, 2026).

Step 1: The Leak Test

American Standard’s Cadet and VorMax support page starts with the diagnosis, and its Champion pages follow the same order: a running toilet is “most likely due to one of the following four components that must be replaced: flapper/seal, flush valve, fill valve, and/or trip lever,” and “Determining which component is faulty will depend on a simple leak test you can conduct.” The VorMax page spells the test out: “Allow the tank to fill to approximately ½” below the overflow tube on the flush valve, then close the water supply shutoff valve to turn the water off. Mark the water level inside the tank, let it sit overnight, and check the water level in the morning.”

Read the result the way American Standard does. Level dropped to the flapper: the flapper or seal. Level dropped to the bottom of the flush valve: the flush valve. “The water did not drop at all. The issue is most likely the water control (fill) valve.” Its fill valve symptoms: “The water continues to go over the top of the overflow tube on the flush valve. The water control valve is hissing or continually dripping water through the refill tube into the overflow tube on the flush valve. Water is not filling at all into the tank, or starts and stops erratically.”

Step 2: One Fill Valve for Cadet, VorMax and Champion

Unlike the flappers and flush valves, which differ by line, American Standard names the same fill valve on every one of those pages: the Universal Toilet Water Fill Valve, part number 7381125-400.0070A. The Cadet/VorMax page says “For either of the American Standard Cadet or VorMax toilets,” check the flush-out article “before replacing The Universal Toilet Water Fill Valve part number 7381125-400.0070A,” and the Champion pages (the general one and the versions for the 3280.040 one-piece and 7381983-400 two-piece flush valves) point to the same part. Its product page calls it the “Fill Valve Universal 400A-Repair Part” and says it “includes valve, shank washer, lock, coupling nuts, coupling washer, refill tube and refill tube clip.”

Step 3: Flush It Out Before You Replace It

American Standard’s standing advice is to clear the valve first: “Sometimes debris can get stuck inside the fill valve causing it to run continuously.” Its method: “if the fill valve will not turn off, remove the cap assembly and inspect for debris in the valve body seat. Use an inverted cup over the uncapped valve body and turn the water on all the way for three or four seconds then turn off. Do this twice to rinse out the valve. Remove and clean the seal and the cap assembly then reinstall.” If it still runs after that, replace it.

I send an occasional note when a new guide goes up — repairs worth doing yourself, and the parts that actually last. No spam, no course funnel; written by a licensed Georgia plumber.

Step 4: Replace the Fill Valve

American Standard’s own steps for the 7381125-400.0070A, in its order: “Turn off the water supply and disconnect the hose from the bottom of the tank. Remove as much water from the tank as possible by flushing continuously. Remove all remaining water in the tank by using a cup and/or a sponge. Unfasten the plastic nut from the inlet valve. Remove the tank lid from the tank. Disconnect the refill tube from the overflow tube on the flush valve. Remove the old fill valve and replace it with the new fill valve. Attach the fill tube to the overflow tube on the flush valve. Fasten the plastic nut securely to the bottom of the fill valve. Reconnect the hose to the bottom of the tank, turn the water supply on, and return the lid to the tank.” Then: “It may be necessary to adjust the water level for the fill valve after installation.”

Finding the Model Number

The fill valve is universal, but the flapper, flush valve and especially the trip lever are not; American Standard says “trip levers are unique to the specific toilet tank, so locating the toilet model number will be necessary.” Its directions: “Carefully remove the tank lid, and place it gently on the floor. You’ll notice a four-digit number located on the back of the tank, near the water level mark. This number will be stamped into the china or as a stamp with a barcode. This is the tank model number. If the number starts with a two, it is a one-piece toilet. If the number starts with a four, it is a two-piece toilet.” With that number you can search its parts store, and American Standard also publishes a ‘Toilet Replacement Parts Service Guide.’

American Standard’s parts store also lists a second fill valve, the 7381334-400.0070A “FILL VALVE – WDI,” with no description of which toilets it fits. None of the support pages we read name it, so if your tank came with a WDI-marked valve, confirm the part against your tank number before ordering.

One alternative worth knowing about:

• Fluidmaster 400A Brass Shank Universal Toilet Fill Valve — if you would rather fit a generic universal valve; Amazon-sold on September 24, 2026. Fluidmaster lists it as best for toilets made before 1994 that use 3.5 to 7 gallons per flush, and lists its 400H for 1.28 to 3.5 gallon toilets. Our Korky vs Fluidmaster comparison covers the universal options.

FAQ

What fill valve does an American Standard Cadet 3 use?

American Standard names the Universal Toilet Water Fill Valve, part number 7381125-400.0070A, for all Cadet models except the pressure-assisted version, and for the VorMax and Champion lines as well.

What fill valve does an American Standard Champion use?

The same 7381125-400.0070A universal fill valve. American Standard’s Champion pages for both the 3280.040 one-piece flush valve and the 7381983-400 two-piece flush valve point to it.

How do I know if the fill valve is bad on an American Standard toilet?

Do its overnight leak test: fill the tank, shut the supply, mark the level and check in the morning. If the level did not drop, the fill valve is the likely fault, especially if water runs over the overflow tube, the valve hisses, or the tank fills in fits and starts.

Where is the model number on an American Standard toilet?

Inside the tank, on the back wall near the water level mark: a four-digit number stamped into the china or on a barcode stamp. A number starting with 2 is a one-piece toilet; 4 is a two-piece.

Can I fix a running American Standard fill valve without replacing it?

Often. American Standard says to remove the cap assembly, check the seat for debris, hold an inverted cup over the open valve body and turn the water on full for three or four seconds, twice, then clean the seal and cap and reinstall. Replace the valve if it still runs.

Why Trust Plumbing Picks

Plumbing Picks is written by a licensed Georgia journeyman plumber. Every part number, model list, size, setting and fit on this page comes from the manufacturer pages and documents listed below, which we opened and read; product details come from those makers and from the Amazon listings, not from hands-on testing. Each linked product was shipped or sold by Amazon, new and in stock, when we checked on September 24, 2026. Where a link goes to Amazon we may earn a commission at no extra cost to you. Nobody pays to be included here. More on who writes this and how we pick.

Sources

• American Standard: What parts do I need if I hear water running in my VorMax toilet? (FAQ 99)
• American Standard: How do I fix a running Cadet and VorMax toilet? (FAQ 1121)
• American Standard: How do I fix a running Champion toilet? (FAQ 46)
• American Standard: Running Champion one-piece toilet with the 3280.040 flush valve (FAQ 836)
• American Standard: Running Champion two-piece toilet with the 7381983-400 flush valve (FAQ 834)
• American Standard: How do I replace the fill valve in a toilet tank? (FAQ 118)
• American Standard: Flushing Out A Toilet Fill Valve (FAQ 1417)
• American Standard: Where can I find the model number of my toilet? (FAQ 1122)
• American Standard: What information is needed to identify parts? (FAQ 1153)
• American Standard: Fill Valve Universal 400A Repair Part (7381125-400.0070A)
• American Standard: 7381334-400.0070A Fill Valve (WDI)

Bottom Line

Leak test first, cup of water second, new valve third. For a Cadet, VorMax or Champion, the fill valve is the 7381125-400.0070A universal; the flapper and flush valve are line-specific, and the trip lever needs the four-digit tank number from inside the tank. So does the tank-to-bowl kit; our tank-to-bowl gasket guide lists it by tank.