Dometic Flush Ball Seal Kit for 300/400 Series & Sealand RV Toilets — OEM replacement, chemical-resistant elastomer

The Dometic Flush Ball Seal Kit is the factory replacement seal for Dometic and Sealand 300/400 series toilets, restoring a watertight bowl closure and odor control.

If your RV toilet shows signs of leakage, a sticky flush ball, or faint odors, worn seals are often the cause. This genuine Dometic OEM kit replaces the original flush ball seal with materials chosen for chemical resistance and long life, ensuring the flush mechanism closes cleanly and reduces the chance of bowl water seeping into the toilet base or the holding tank area.

How will replacing the flush ball seal stop leaks and smells?

Over time, exposure to cleaning chemicals and waste can harden or deform the elastomer seal, compromising its ability to form a full, leak-proof closure. Installing a new Dometic seal restores the intended contact between the flush ball and the seat, preventing water from escaping and helping to contain odors within the bowl and holding tank.

• OEM elastomer matches original dimensions for proper sealing.
• Chemical-resistant material resists degradation from cleaners and waste.
• Precision fit prevents gaps that cause slow leaks and smell migration.

Will this kit fit my 300 or 400 series Dometic or Sealand toilet?

Yes—this is the genuine Dometic OEM replacement designed specifically for the 300 and 400 series models and compatible Sealand toilets. Because it’s made to factory specifications, it replaces the original part without modification, maintaining safe and reliable operation.

• Direct OEM compatibility with Dometic 300 and 400 series toilets.
• Works with matching Sealand models that use the same flush assembly.
• No trimming or adapters required for correct installation.

How difficult is installation and what tools are needed?

Installation is straightforward for anyone comfortable with basic RV maintenance: remove the old seal, clean the seating area, and fit the new OEM seal in place. The kit is designed for a direct swap so you can avoid complex modifications or specialized equipment.

• Typical tools: screwdriver set and a soft rag or mild cleaner.
• No adhesives or special bonding agents required.
• Replacement typically takes less than an hour for most DIYers.

What advantages does the genuine Dometic part offer over aftermarket options?

Genuine Dometic parts are manufactured to the same tolerances and materials as the original component, which helps preserve the toilet’s intended performance and long-term durability. Using OEM parts also reduces the risk of improper fit or premature failure that can arise with generic substitutes.

• Factory-direct materials and dimensions for reliable sealing.
• Helps retain manufacturer recommendations and service standards.
• Reduces risk of warranty issues linked to incompatible parts.

Who is this for: RV owners, campground hosts, and mobile-service technicians who maintain Dometic or Sealand 300 and 400 series toilets and want a dependable, factory-quality replacement part. If you’re experiencing bowl leaks, lingering odors, or a flush ball that sticks, this OEM seal kit provides a precise, durable repair that keeps your restroom sanitary and functioning as intended. Choosing the genuine Dometic kit helps ensure correct fit, chemical resistance, and consistent performance over time.