COMPATIBILITY FIRST · NO INTRO ADS
Replace a two-piece toilet
Representative installation: TOTO Eco Drake CST744E, a floor-mounted, 12-inch-rough-in two-piece gravity toilet with C744E bowl and ST743E 1.28-gpf tank, onto an existing sound flange and stable finished floor. Its tank uses a conventional two-bolt connection.
- CST744E uses the ST743E tank and C744E elongated bowl with a nominal 12-inch rough-in. Measure from the finished wall, not the baseboard, to the flange/bolt centerline; confirm room and supply clearances from the specification.
- Choose a new wax seal for the actual outlet/flange installation and follow its instructions; do not assume a thicker ring or stacked rings repairs a flange problem.
- Have the matched tank gasket and two-bolt hardware, new closet-flange bolts, a compatible elongated seat and a correctly sized flexible toilet supply line. The wax ring, floor bolts, seat and supply line are separate items.
- The tank kit uses two rubber washers, four metal washers and four metal nuts: one washer/nut pair seals each bolt under the tank, and another pair secures each bolt below the bowl. Three ceramic contact points support the tank; they are not three fasteners.
- For a back-to-back installation sharing a drain stack, have a qualified plumber confirm the drainage arrangement meets TOTO’s stated requirements before proceeding.
The animation shows the flapper-equipped ST743E version. Some ST743E tanks use a tower; the exact tank’s part diagram and supplied hardware instructions control. Preserve correctly assembled factory internals, and follow the instructions for your exact revision if they differ.
01 / DIAGNOSE BEFORE BUYING
Confirm the repair fits the problem.
- Replacement may suit damaged china or a chosen upgrade; running water alone often needs a smaller internal repair.
- For water near the base, first distinguish water running down from a supply or tank leak from a failed floor seal. A persistent or unidentified leak needs diagnosis.
This procedure does not cover
- Wall-hung, rear-outlet, macerating, pressure-assisted, electronic and concealed/skirted mounting systems
- Drain relocation, flange replacement, structural floor repairs or changing supply plumbing
- A damaged or excessively recessed flange, uncertain seal height, or a toilet that rocks on a dry fit
02 / COMPATIBILITY & PREPARATION
Have the matching parts ready.
- Helper or suitable lifting assistance; gloves and eye protection
- Adjustable wrench, screwdriver, putty knife, measuring tape and level
- Bucket, sponge, towels, padded staging surface and a retrievable drain-cover rag
- Complete matched CST744E toilet (C744E bowl + ST743E tank), new matched tank gasket and two-bolt mounting kit, new floor bolts and wax ring selected for the sound flange, compatible supply line and seat
These checks are for your use. They do not certify compatibility and are not saved.
03 / STRAIGHT TO THE REPAIR
See how the parts move.
Read the narration transcript
Shut off the toilet supply, flush, and verify no refill before disconnecting it. Drain the tank and bowl. This example installs a two-bolt TOTO Eco Drake on a sound flange with a twelve-inch rough-in. Check the finished-wall measurement and clearances first. Get help for lifting; ceramic is heavy and can break into sharp pieces. Remove the old lid and tank, then undo the floor nuts and release any base sealant. Lift the bowl away. Cover the drain with a retrievable rag, scrape away old wax, and inspect the flange and floor. Stop for a loose or broken flange, soft flooring, or uncertain seal height. Check that the new bowl sits stable before adding wax. Fit new bolts and a correctly selected wax ring. Remove the rag, lower the bowl straight onto the bolts, and press evenly to seat it. Don’t move it afterward; if lifted, replace the wax. Install washers and nuts evenly without overtightening or using them to pull the bowl down. Prepare the matching tank on padding. Seat the round gasket over the flush-valve nut. Each bolt has a rubber washer inside, then a metal washer and sealing nut under the tank. Follow this model’s hardware instructions. Align both bolts and lower the tank straight. Add metal washers and nuts beneath the bowl. Finger-tighten, check level, then tighten evenly until all three ceramic support points meet. Do not overtighten. Flush the supply into a bucket as directed. Close it again, connect the tank end finger-tight without twisting, then restore water slowly. Flush several times, checking the supply, tank joint and base, then recheck at rest. Stop for any leak or rocking. Fit the seat and lid only after the installation passes.
04 / THE PROCEDURE
Work gently. Check as you go.
- Check fit and arrange help Confirm the exact toilet dimensions, rough-in and supply clearance. Clear a safe lifting route. Ceramic is heavy, brittle and sharp when broken; do not lift the assembly by its tank.
- Isolate and empty Shut off the toilet supply, flush, and verify no refill. Remove remaining tank and bowl water. Disconnect the supply over a bucket. Failed isolation or a moving pipe is a stop condition.
- Remove the old fixture Take off the lid and, for a two-piece toilet, remove the tank using its model-specific procedure. Remove floor-bolt caps and nuts and release any base sealant. Lift the bowl with help; do not pry hard against the ceramic.
- Inspect the foundation Cover the open waste pipe temporarily with a retrievable rag. Remove old wax and bolts. Inspect the flange, anchorage and surrounding floor. Stop for a cracked/loose flange, rot, soft flooring or uncertain flange height; a new seal cannot fix these.
- Verify a stable fit Before fitting wax, check that the bowl can sit level and stable at the correct location. Do not use bolts to pull a rocking toilet flat. Resolve instability with qualified help before proceeding.
- Set a fresh seal Fit new flange bolts with their threaded ends upward. On a padded surface, fit the correctly selected new wax ring around the bowl’s outlet horn, following TOTO and seal instructions. Remove the drain-cover rag. With help, lower the bowl straight over the bolts and press evenly on both sides of the rim to seat it. Do not shift or tilt it afterward; if lifted or the seal is disturbed, start with another new wax ring.
- Fasten the bowl Install the specified cap bases, washers and nuts in the illustrated order. Tighten evenly only enough to secure the stable bowl. Never overtighten or use bolts to draw the bowl down. Fit caps once the hardware is secure.
- Install the matched tank Use the ST743E tank and matched gasket with its two-bolt kit. The ring gasket fits over the flush-valve nut. Each bolt has rubber directly beneath its head inside the tank, then a metal washer and sealing nut below the tank; the sealing nut is finger-tight plus 1/2 turn with a wrench. Align both tank bolts with the bowl openings and lower the tank straight, then add the second metal washer and mounting nut below each bowl opening. Start finger-tight, check level and tighten equally until the three designated ceramic support points contact the bowl. Stop there. Follow the detailed tank steps for preparation and the full hardware order; preserve the correctly assembled factory internals.
- Connect and check Briefly flush the disconnected supply line into a bucket to clear debris, then shut it off again. Connect the compatible line without strain or kinks. Tighten the tank’s plastic fill-valve coupling by fingers only, with no wrench; follow the connector instructions at the shutoff end. Restore water slowly. Check supply and tank connections, adjust only to the marked waterline if required, and flush several times while checking around the base. Isolate immediately for leakage.
- Finish only when dry Fit the compatible seat and lid. Follow applicable installation requirements for finishing around the base; sealant must never conceal a leak. Recheck all joints and the base after the toilet has stood.
05 / VERIFY THE RESULT
Check operation and every disturbed joint.
- Bowl and tank remain stable and level; no rocking. The tank rests at its three designated support contacts without extra tightening.
- Supply fills the tank to its mark and shuts off.
- No moisture at the supply, tank fasteners, tank-to-bowl joint or floor perimeter during repeated flushes or afterward.
- If water appears at the base, stop use and diagnose the source; a disturbed/failed wax seal must be renewed, not caulked over.
- Do not use in-tank cleaning products, particularly chlorine-containing cleaners; TOTO warns that they can damage fittings and cause leaks.
KNOW YOUR LIMITS
Stop and get qualified help when…
- Flange damage, loose anchorage, floor rot/softness, uncertain seal height or unstable dry fit
- Cracked ceramic, seized fasteners, unsafe lifting or inaccessible mounting
- Failed shutoff, corroded supply or pipe movement
- Any persistent external leak or poor flush after installation
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MANUFACTURER REFERENCES
Sources & scope.
Written instructions use the manufacturer references below. The 3D illustration is not a manufacturer certification or a substitute for the instructions supplied with your exact model.
- TOTO Eco Drake CST744E specification: ST743E tank + C744E bowl, dimensions and rough-in
- TOTO installation manual 0GU048Z: two-bolt hardware, gasket, three contact points and supply connection
- TOTO CST744E parts drawing: 9BU024E tank gasket, TSU01D mounting kit and internal-part variants
Checked October 15, 2026. These are information links, not affiliate links. We do not sell tools or parts.