Tank Fit

TOTO

Drake vs Drake II: same name, different tank guts

The original Drake (CST743/CST744 family) is a G-Max toilet and shares that system's 3-inch flapper. The Drake II (CST454 family) moved to Tornado Flush with a different flush valve and a different seal. Buying for “a Drake” without checking which one is how people end up with a flapper that hangs on the posts and still leaks.

Which Drake do you have?

The answer is the CST number stamped inside the tank, above the waterline, or on the label on the tank's inner wall. Match it before anything else:

  • CST743 / CST744 family (original Drake): a G-Max toilet. Wide 3-inch flush valve, large soft flapper on a hinge. Everything on the G-Max page applies directly.
  • CST454 family (Drake II): Tornado Flush bowl with a different flush valve — a taller tower-style valve with its own seal rather than the G-Max flapper. The G-Max flapper does not fit it.
  • Not sure: lift the lid. A big hinged rubber flapper lying flat over a wide opening is G-Max. A cylinder or tower that lifts straight up is the Drake II valve.

Which parts cross over, and which do not

  • Flapper/seal: no crossover. G-Max flappers fit G-Max valves (original Drake, Ultramax, and siblings). Drake II takes the seal listed for the CST454 family in TOTO's parts documentation. Neither fits the other.
  • Fill valve: mostly yes. Two-piece Drake tanks generally accept a standard bottom-entry universal valve — measure floor-to-overflow height and use the chooser. This is the one repair where the universal aisle is genuinely your friend on a TOTO.
  • Trip lever and chain: model-specific. Drake II's dual-option trip setups in some trims are not the original Drake's lever.
TOTO THU-series (by CST number)OEM flapper or flush-valve seal for your Draketypically $12–$25
Fits
The CST number stamped in your tank. TOTO's parts diagrams list the flapper or tower seal as a THU part number per model — the G-Max flapper for the CST743 family, the tower seal for the CST454 family. OEM keeps the flush timing and volume TOTO tuned the bowl around, which matters on EPA WaterSense–labeled 1.28 gpf models.
Does not fit
Cross-shopping by 'fits Drake' listing text. Sellers routinely lump every Drake together; the two generations do not share seals.
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Korky 3-inch for TOTO (54BTP class)Aftermarket G-Max-compatible flappertypically $9–$14
Fits
Original Drake (CST743 family) and other G-Max valves with a clean, smooth seat. A reasonable substitute when OEM is backordered — confirm your CST number on Korky's own fitment lookup before buying.
Does not fit
Drake II (CST454 family) — wrong valve entirely, no 3-inch flapper fits the tower. Also any tank where the seat is scaled or scored; fix the seat first (see the flapper-size guide).
Look up current price (affiliate)

Service notes for Drake owners

  1. Hold the waterline. TOTO marks the fill line inside the tank. G-Max flush quality falls off below it; set the fill valve to the mark, not to "close enough."
  2. Chain slack on the original Drake. Half a link of slack, clip the excess. Too much slack is the most common cause of "have to hold the handle" complaints.
  3. No in-tank bleach tablets. TOTO's care documentation warns against in-tank cleaners — they eat the rubber you are about to replace. More on that in hard water and chloramine.
  4. Planning a Washlet? Drake tanks are a common bidet-seat host. Check the clearance notes on seats before ordering the seat.

The CST number is the whole game

"Drake" covers two flush systems across twenty-plus years of production. The four-character CST stamp inside the tank resolves it in one look, and TOTO's parts documentation turns it into an exact THU part number. Photograph the stamp while you are in there.

Next, in the tank