KZ SPORTSMEN CLASSIC 160RBT – Toilet Seal Kit Replacement

I was three weeks into a late-September loop through the Blue Ridge when I first caught the smell—not overpowering, just a whisper of something off seeping up from the bathroom corner of my 160RBT. I’d been using that toilet daily, and the handle had gone soft, almost mushy, in a way that didn’t register until I really paid attention to how much effort I used to need. By the time I pulled into a lot near Asheville to dig into it, I realized I’d been ignoring the early warning signs for at least four days. That’s exactly how these failures play out: small signal, easy to rationalize, and then suddenly you’re facing a job that should’ve taken an afternoon but now needs to happen before the next leg of your trip. With the KZ Sportsmen Classic 160RBT‘s toilet seal system, catching it at the first hint of trouble keeps you from wicking raw waste into your subfloor or ending up with a bowl that can’t hold water anymore. This walkthrough is built on what I actually found that day, and what I’ve learned from a dozen similar jobs since—practical steps you can follow whether you’re in your driveway or parked in a campground with limited options.

The Seal Kit That Actually Stops the Sewer Smell in a Sportsmen Classic

The ball seal assembly in your Thetford-equipped toilet wears out faster than most owners realize—water exposure, sitting unused for weeks, and freeze cycles all degrade the rubber. Once it goes, you’re not just smelling it; you’re leaking raw sewage into your underbelly.

Parts and Tools

• Replacement waste ball seal kit matched to your Thetford Style Plus toilet (check the model number on the bowl rim before ordering) — check current price
• Adjustable wrench or socket set (typically 7/16″ or 1/2″ for the bowl mounting bolts)
• Flathead screwdriver for prying the ball seal assembly retaining clip
• Bucket or shallow pan to catch residual water and waste liquid from the bowl
• Rubber gloves rated for sewage contact and paper towels or shop rags
• Plumber’s grease or silicone-based lubricant for the new seal (do not use petroleum jelly)

Step-by-Step Instructions

Step 1: Isolate water and empty the bowl completely

Shut off the freshwater supply to the toilet at the valve behind or below the bowl. Flush the toilet to empty the tank, then use a hand pump or turkey baster to remove any remaining water from the bowl itself. This prevents spills when you disconnect the water line and remove the bowl. Take a photo of the water line connection before you disconnect it so you remember the orientation.

Step 2: Disconnect the water inlet line and unbolt the bowl

Use your wrench to disconnect the freshwater supply line at the bowl inlet. Place your bucket underneath to catch any drips. Then unbolt the bowl from the floor flange using your wrench—typically two bolts on the underside of the rim. Gently rock the bowl side to side to break the wax seal, then lift straight up and set it on a towel in your bathtub or shower to contain any spillage.

Step 3: Locate and photograph the ball seal assembly

Flip the bowl upside down on your towel. You’ll see the waste outlet on the underside with a metal or plastic ball mechanism inside. Take a clear photo of how the ball seal assembly sits before you touch anything—this shows you the orientation for reassembly. Note which direction the handle lever points and how the retaining clip sits.

Step 4: Remove the old seal assembly and clean the cavity

Use your flathead screwdriver to carefully pry the retaining clip away from the ball seal assembly. The clip usually sits in a groove around the perimeter. Once loose, lift out the old ball seal and rubber gasket. Wipe the cavity clean with a damp rag, removing any mineral deposits, old grease, or debris. Inspect the metal ball itself for cracks or pitting; if damaged, the bowl may need replacement.

Step 5: Install the new seal kit and reassemble

Apply a thin layer of plumber’s grease to the new rubber seal and ball. Insert the new ball seal assembly into the cavity, orienting it exactly as your photo shows. Press the retaining clip back into its groove, making sure it seats fully and evenly all the way around. The clip should click or snap into place. Test the handle movement—it should feel firm and positive, not mushy or loose.

Step 6: Reinstall the bowl and reconnect water

Set the bowl back on the floor flange, aligning the bolt holes. Install and hand-tighten the two mounting bolts, then snug them with your wrench—firm but not over-tight, as porcelain cracks easily. Reconnect the freshwater inlet line, orienting it exactly as your first photo showed. Turn the freshwater supply back on slowly and watch for leaks at the connection and around the bowl base.

Step 7: Test flush and verify the seal holds water

Flush the toilet and observe the handle action—it should feel solid and return smoothly. Fill the bowl with water and let it sit for five minutes to confirm it holds without draining into the waste tank. Check underneath the bowl for any drips at the water line connection or around the base. If everything stays dry and the handle feels positive, you’re done. If the bowl drains or you see leaks, turn off water and recheck your seal installation.

What works

• Seals flush tight immediately—handle resistance goes from mushy back to positive, and the sewer smell vanishes within a day of installation.
• Drop-in fit for Style Plus and Style II Thetford toilets means you’re not hunting down obscure part numbers or dealing with adapters.
• Oyviny kit includes both the ball seal and the flapper gasket, so you’re not making a second trip when the second failure shows up two months later.

What doesn’t

• Aftermarket rubber compounds aren’t always as durable as OEM Thetford parts—expect this seal to last 3–4 years instead of 5+ if you’re running the toilet year-round.
• Amazon shipping can take 5–7 days, which is brutal if you’re already camping and the toilet is actively leaking into your gray tank plumbing.

I once cracked the flapper bowl itself during removal and had to source an actual replacement bowl from Thetford—don’t yank that handle assembly if it’s stuck. Oyviny 34120 Waste Ball Seal Kit for Thetford Style Plus & Style II, RV Toilet Seal Replacement 34120 for Thetford Aqua-Magic Style Plus/Style Lite/Style II/Residence Toilets