TOMOON RV Toilet Seal Replacement 2-Pack for Dometic 300/310/320 — Rubber Flush Ball Gaskets, Leak & Odor Protection

TOMOON’s 2-pack RV toilet ball-seal kit replaces Dometic 300/310/320 Part #385311658 to stop leaks and control odors quickly and reliably.

If your camper or travel trailer uses a Dometic 300/310/320 toilet and you’re dealing with slow leaks, odor seepage, or a failing flush ball gasket, this replacement kit is engineered to be a drop-in solution. Each set contains two premium rubber seals shaped to the exact dimensions of the original Dometic part so you can swap the worn seal and keep a spare on hand for future trips. The design focuses on long-term flexibility and resistance to temperature shifts and road vibration, giving a more durable alternative to low-cost aftermarket seals.

How will these seals stop leakage and smells?

The replacement seals use a high-grade rubber compound that maintains a snug, reliable fit around the flush ball even after repeated use. The material resists compression set and will not harden in cold weather, which prevents common gaps that cause leaks and odor escape. Proper installation restores the toilet’s designed barrier between bowl and holding tank.

• Exact profile matching Part #385311658 for a tight, OEM-style fit
• Wear-resistant rubber minimizes deformation over time
• Maintains seal integrity in low temperatures and rough roads
• Prevents water seepage and reduces odor backflow into the cabin

What makes this 2-pack a better value than a single seal?

Buying two seals gives you an immediate replacement and a ready spare, which is especially useful on lengthy trips or seasonal camping. Keeping a backup reduces downtime and avoids emergency parts runs when you’re away from service centers. The pack offers cost savings compared with repeatedly buying single, lower-quality seals that fail early.

• One seal installed, one stored for emergencies or scheduled maintenance
• Lower cost per seal compared with single purchases
• Perfect for multi-season RV upkeep or long-distance travel
• Prevents unexpected toilet downtime during trips

Is installation difficult—do I need special tools?

No special tools or advanced plumbing skills are required. The seals are made to be pressed into place quickly after removing the old gasket and cleaning the mating surfaces. Most users report completing the swap in under five minutes, making it easy to service on the road.

• Remove old seal, clean flange, press new seal into position
• No cutting, adhesives, or special tools required
• Installation recommended after shutting off fresh water supply
• Simple maintenance (light silicone lubrication) extends service life

Will these seals hold up in cold weather and on rough roads?

The compound and design prioritize flexibility and resilience so the gasket remains functional across a wide range of temperatures and during off-road travel. Reinforced material resists cracking and maintains a tight barrier despite vibrations or repeated cycling of the flush mechanism.

• Formulated to resist hardening in cold climates
• Durable under frequent vibration and rough terrain
• Maintains consistent seal pressure to avoid leaks
• Regular light lubrication helps preserve elasticity

Who is this for? RV owners, campers, and travel-trailer enthusiasts with Dometic 300/310/320 toilets who want a reliable, long-lasting replacement for Part #385311658. It’s aimed at DIY-minded users who prefer a quick, tool-free fix and value having a backup part for extended trips. If you need to stop seepage and odor without replacing the entire toilet, this TOMOON 2-pack is a practical, cost-effective solution.