Grundig 3-in-1 RV Toilet Seal & Flange Kit for Dometic 300 310 320 | Replaces 385345892, 385311658, 385311652

I. Product Overview

If water is pooling around the base of your Dometic 300, 310, or 320 toilet — or odors are creeping into the bathroom — this 3-in-1 seal kit fixes the leak at its source. It replaces the three parts that wear out over time: the 3" socket floor flange, the flush ball seal, and the base seal.

Pull the toilet, swap the parts, and be back on the road in about 30 minutes — no mobile tech, no dealer service call.

II. Product Features

• Direct OEM Replacement: The flange and both seals swap in like-for-like — same fit, same function, no modifications needed.
• Stops Leaks and Black Tank Odors: New flange and seals keep wastewater under the toilet and black tank odors out of your living space.
• Built for Life on the Road: Withstands repeated flushing, miles of highway vibration, and temperature swings for long-term, leak-free service.
• Everything in One Box: All three wear parts plus all mounting hardware included — open the box and start the repair.

III. Product Specifications

• Product Type: RV Toilet Seal and 3" Socket Flange Repair Kit (3-in-1)
• Replaces Part #: 385345892 (3" Socket Floor Flange), 385311658 (Flush Ball Seal), 385311652 (Base Seal)
• Compatible With: Dometic 300 / 310 / 320 Series RV Toilets
• Estimated Install Time: About 30 minutes with basic hand tools
• Package Dimensions: 18 x 18 x 10 cm (7.1 x 7.1 x 3.9 in)
• Item Weight: 435 g (15.3 oz)

IMPORTANT: NOT compatible with residential plumbing, standard home toilets, or any Dometic toilet series other than 300 / 310 / 320. Please verify your toilet model before purchase.

IV. Package Includes

• 1 x RV Toilet 3" Socket Floor Flange (385345892)
• 1 x Flush Ball Seal (385311658)
• 1 x RV Toilet Base Seal (385311652)
• 2 x Gland Gasket
• 1 x Seal Ring
• 2 x Nut
• 2 x Bolt
• 4 x Self-Tapping Screw
• 4 x Expansion Anchor

V. Precautions

• Check Base Dimensions Before Ordering: The replacement flange may look slightly smaller than your original OEM part while still seating correctly. Measure your toilet's base dimensions to confirm a snug fit.
• Turn Off the Water Supply: Shut off the water supply to the toilet and flush to release any remaining pressure in the lines before removing the old flange and seals.
• The Toilet Must Be Removed: Replacing the flange and base seal requires lifting the toilet off the floor. Disconnect the water line first, then unbolt and lift the toilet straight up.
• Install All New Seals: Replace the flange, flush ball seal, and base seal together. Reusing an old seal is a common cause of recurring leaks.
• Clean the Mounting Surface: A reliable seal depends on a debris-free surface, so wipe away old sealant, dust, and residue before installing the new parts.
• Use Proper Tools: Basic hand tools are required but not included. Do not over-tighten the screws, as this can crack the flange or damage the mounting points.
• Check for Leaks After Installation: Turn the water supply back on, flush several times, and inspect the toilet base and all connections for leaks.
• Cold Weather Notice: If you store your RV in freezing temperatures, drain the water system completely to prevent freeze damage.