JAYCO JAY FLIGHT 174BH – Toilet Seal Kit Replacement

Most people buy a used RV and assume the toilet just works — that it’s either functional or it isn’t, with nothing in between. That’s wrong. A Jayco Jay Flight 174BH toilet can leak for months without you ever knowing it’s happening, draining black water slowly into the subfloor, rotting wood, breeding mold, and creating a smell that no amount of chemicals will fix. The seal kit is invisible, buried under the bowl, and it fails quietly. But here’s what separates a savvy buyer from someone who gets surprised six months later: you can spot that failing seal during a walkthrough, use it to negotiate $500 or $1,000 off the asking price, and then spend 90 minutes and $20 to solve it yourself. I’ve used this exact diagnostic approach on dozens of used RVs, and the toilet inspection almost always uncovers negotiating room. This walkthrough shows you how to recognize the problem, what the replacement actually involves, and why doing this right the first time matters far more than the part cost.

Sealing the Leak: Finding and Replacing the Thetford Waste Ball Kit

The waste ball and floor seal assembly on Thetford Aqua Magic toilets deteriorates out of sight — by the time you detect the odor or spot dampness under the rig, the decay has already started. Catching this early and swapping the seal kit yourself means you’re looking at a quick afternoon job instead of a structural repair nightmare.

Why this kit actually solves it

• Both the waste ball seal and the floor gasket arrive together in one package — no hunting for a second part halfway through the job.
• The replacement waste ball seal actually stops the seepage; you’ll flush afterward and see a completely dry floor underneath the toilet base.
• Engineered specifically for the Thetford toilets Jayco installs in the 174BH — bolt-on compatibility means no adapters, no improvisation, no guessing.

Where the friction shows up

• You’ve got to pull the entire toilet off the floor and disconnect the black water line — expect 30 minutes of fumbling if you haven’t tackled this before.
• Sellers on Amazon list this kit under three different Thetford model numbers; grab the wrong one and you’ll discover mid-installation that the seal diameter doesn’t match your bowl.

I second-guessed whether the floor seal gasket I pulled out was actually the problem until I ran water through the fresh seal and watched it hold completely dry underneath — no weeping, no staining. Get the Ophjerg 34120 & 12524 RV Toilet Seal Kit for Thetford – Complete Waste Ball Seal and Floor Seal Replacement for Aqua Magic Style Plus, Style II, Style Lite & Residence Toilets before the leak turns into a floor repair.

Parts and Tools

• Replacement waste ball seal and floor gasket kit matched to Thetford Aqua Magic toilet model — check current price
• Adjustable wrench or socket set for removing toilet bowl bolts
• Flathead screwdriver for prying and disconnecting water supply line
• Bucket or shallow pan to catch residual water from bowl and tank
• Rags or towels for cleanup and drying surfaces
• Silicone-based RV toilet lubricant or plumber’s grease for reassembly

Step-by-Step Instructions

Step 1: Shut off water and empty the system

Locate the water shutoff valve behind or beneath the toilet and turn it clockwise until tight. Flush the toilet to drain the bowl and tank completely. If water remains, use a sponge or turkey baster to remove it. This prevents spills when you disconnect the supply line and remove the bowl. Take a photo of the water line connection before you touch anything—you’ll need to remember how it sits.

Step 2: Disconnect the water supply line

Use an adjustable wrench to loosen the compression fitting where the water line meets the fill valve. Turn it by hand once it’s loose enough. Gently pull the line away and let any remaining water drip into your bucket. If the line is kinked or cracked, note it—you may need to replace it too. Set the line aside where it won’t get stepped on.

Step 3: Remove the toilet bowl from the base

Locate the two bolts securing the bowl to the floor flange, usually hidden under plastic caps or trim rings. Pry the caps off with a flathead screwdriver. Unbolt both fasteners with your wrench, turning counterclockwise. Gently rock the bowl side to side to break the old seal, then lift straight up and set it upside down on a towel. Inspect the old floor gasket—it should be cracked, hardened, or visibly deteriorated.

Step 4: Remove the old waste ball seal from the bowl

Turn the bowl upside down and locate the waste ball assembly underneath—it’s the black rubber ball mechanism. Look for the retaining clip or bolt holding it in place. Remove it with your wrench or screwdriver. Pull the old waste ball seal straight down and out. Inspect the ball itself for cracks or permanent deformation. Clean the mounting surface inside the bowl with a rag to remove old lubricant and debris.

Step 5: Install the new waste ball seal

Apply a thin coat of RV toilet lubricant to the new waste ball seal. Insert it into the bowl opening from underneath, aligning the mounting holes. Secure it with the retaining clip or bolt, tightening firmly but not so hard you crack the plastic. The ball should move freely when you gently push it. Wipe away excess lubricant with a rag.

Step 6: Install the new floor gasket and remount the bowl

Place the new floor gasket onto the floor flange, centering it over the opening. Apply a light bead of RV-safe silicone around the gasket perimeter if recommended by the kit instructions. Carefully lower the bowl straight down onto the gasket, aligning the bolt holes. Insert both bolts and hand-tighten them first, then use your wrench to snug them evenly—alternate between bolts to avoid tilting the bowl. Do not overtighten; you’ll crack the porcelain.

Step 7: Reconnect water and test for leaks

Reattach the water supply line to the fill valve, hand-tightening first, then using your wrench to snug the compression fitting. Turn the water shutoff valve counterclockwise to restore supply. Flush the toilet three times and watch for leaks at the base, under the bowl, and at the water line connection. Check underneath the rig with a flashlight to confirm no water is dripping into the subfloor. If everything is dry after 10 minutes, the job is complete.