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Gerber Plumbing Part

Gerber Tank Gasket

Gerber tank-bowl gasket replacementStandard universal 3-inch pattern. Bemis 7530 ($5-$10) fits all Gerber models. 45-minute service requiring tank removal. Shut off water, disconnect supply, remove ta

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Updated May 2026 · Gerber Plumbing Toilets

Gerber tank-to-bowl gasket replacement

The tank-to-bowl gasket seals the joint between the bottom of the Gerber tank and the top of the bowl. Gerber uses the standard universal 3-inch tank-bowl gasket pattern. Bemis 7530 at $5-$10 from any Home Depot fits all Gerber two-piece residential models directly.

When to replace

  • Water leak between tank and bowl during flush
  • Visible water at tank-bowl joint after flushing
  • Bowl water drops slowly when toilet not in use (joint leak)
  • Removing tank for any reason (preventive maintenance)
  • Tank-bowl bolt heads visibly corroded

Gerber gasket compatibility

  • Avalanche 21-808 + 21-810: standard 3-inch (Bemis 7530)
  • Maxwell 21-712: standard 3-inch
  • Viper 21-014: standard 3-inch
  • Logan Square 21-218: standard 3-inch
  • Hinsdale Compact 21-006: standard 3-inch
  • Wicker Park 21-318: one-piece (NO tank-bowl gasket — bowl and tank molded as single unit)

Replacement procedure (45 minutes — tank removal required)

  1. Shut off water at under-toilet shutoff valve.
  2. Flush to empty.
  3. Sponge out remaining water from tank and bowl.
  4. Disconnect supply line.
  5. From inside tank, remove tank-bowl bolt heads.
  6. From under bowl, hold nut with wrench while loosening from inside tank.
  7. Two-person: lift tank straight up off bowl.
  8. Set tank aside on soft surface.
  9. Remove old gasket from flush valve outlet on bottom of tank.
  10. Clean both mating surfaces with vinegar.
  11. Install Bemis 7530: press over flush valve outlet.
  12. Two-person: lower tank back onto bowl, align bolt holes.
  13. Insert new brass tank-bowl bolts.
  14. Cross-tighten bolts alternately, 1/4 turn at a time, until snug. Stop at snug + 1/4 turn.
  15. Reconnect supply line. Restore water.
  16. Test 3-5 flushes. Check for leaks.

Common Gerber tank-bowl gasket service mistakes

  • Bolts overtightened: Cracks porcelain at mounting flange. Snug + 1/4 turn limit.
  • Bolts undertightened: Gasket doesn't fully compress.
  • Old gasket fragments left behind: Incomplete cleaning means new gasket doesn't seal flush.
  • Pre-corroded bolts reused: May strip under torque. Replace bolts ($3-$5 brass set).
  • Wrong gasket diameter: Gerber uses standard 3-inch — not Eljer's wider 3.25" pattern.

Bolt corrosion service

Gerber toilets in humid bathrooms commonly have tank-bowl bolts corroded after 15+ years. If bolts won't unscrew:

  1. Apply penetrating oil (PB Blaster). Wait 30 minutes.
  2. If still seized: hacksaw or Dremel through bolt head from inside tank.
  3. Drill out bolt remnants from underneath bowl with 1/4" bit.
  4. Replace with new brass bolts AND new Bemis 7530 gasket.

Where to buy

  • Home Depot: Bemis 7530 at $5-$8
  • Lowes: Bemis 7530 at $5-$8
  • Amazon: Bemis 7530 at $4-$7
  • Korky alternative: Korky 449 universal 3-inch at $6-$11
  • Plumbing supply: Gerber OEM gasket + universal tank-bowl bolt kit

Preventive maintenance bundle when replacing gasket

Since you're removing the tank, also replace: flapper (Korky 2032BP, $7-$12), fill valve (Fluidmaster 400A, $10-$15), supply line (12" braided, $5-$10), tank-bowl bolts (brass set, $3-$5). Total bundle: $30-$50 in parts. Eliminates 3-5 separate service touches over next 5-10 years.