How to Replace an RV Toilet Flange

How to Replace an RV Toilet Flange
The toilet flange is not an often-replaced part in an RV. Usually it's replaced only when newly installed flooring sits at a different height than the original flooring, making the flange height too low or too tall. Flange replacement is not a pleasant job, so think carefully before you decide to take on the task. If it can be avoided, avoid it. If it must be done, set aside the whole day to complete the job.

Instructions

Difficulty: Challenging

Things You’ll Need:
  • Wrench (size depends on model of toilet)
  • Putty knife
  • Screw drive (size depends on model of RV)
  • Angle grinder
  • Flashlight
  • Chisel
  • Marine adhesive
  • Rubber flange seal
Step 1
Flush out your black water tank. While this is not a necessary step for replacing the toilet flange, it makes the job more pleasant. An RV flange attaches directly into the black water holding tank, so a clean tank means less odor during the job.
Step 2
Turn off or disconnect the water going into the RV. Flush the toilet to empty the water from the bowl. Disconnect the water lines to the toilet.
Step 3
Remove the bolts holding the toilet down. Depending on the model toilet, two to four bolts are at the base of the toilet. Pull the toilet up and set it aside.
Step 4
Remove the flange seal. The flange seal is made of either rubber or wax. If it is a wax seal and has melted to the flange, use a putty knife to scrape off the wax.
Step 5
Remove the screws holding the flange to the floor. Commonly, the screws are stuck and difficult to remove. Use an angle grinder, if needed, to cut the bolts off.
Step 6
Shine a flashlight down the pipe leading to the black water tank to see how the flange is attached. The flange attaches approximately 1 to 3 inches down the tube. Usually, the flange screws into the tank. Sometimes, the flange is glued or cemented into the tank.
Step 7
Disconnect the flange. If the flange is screwed into the tank without any glue or cement, twist the flange counter-clockwise to detach it from the tank. Corrosion makes the flange hard to turn, so you have to put some muscle into your turning action. To remove a glued or cemented flange, hit the glued or cemented part with a chisel until you break the seal. Breaking the glue or cement bond requires a quite a bit of force and numerous hits with the chisel. Once you break through the glue or cement, twist or pull the flange off the black water tank.
Step 8
Install the new flange by screwing it clockwise into the black water tank. If you have one of the few tanks that do not have a screw in attachment for the flange, glue the flange into place using a waterproof marine adhesive.
Step 9
Replace the screws into the flange to hold the flange to the floor. If you previously cut the screws, install new ones.
Step 10
Set a new flange seal on top of the flange. Use a rubber flange seal, even if your prior flange seal was wax. Wax flange seals are not appropriate for RVs because they melt.
Step 11
Reinstall the toilet, reversing the toilet removal instructions.

Tips & Warnings

 
If you have a screw-in flange, you can often adjust the height by unscrewing it a bit or screwing it in tighter.
 
Apply some grease to the threads on the new flange to make future removal easier.
 
The excessive force used to remove the flange may break the flange, black water tank or both.

Article Written By Rose Kivi

Rose Kivi has been a writer for more than 10 years. She has a background in the nursing field, wildlife rehabilitation and habitat conservation. Kivi has authored educational textbooks, patient health care pamphlets, animal husbandry guides, outdoor survival manuals and was a contributing writer for two books in the Uncle John’s Bathroom Reader Series.

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