Monday, May 28, 2018

Thetford Waste Ball Seal Repair

Posted from Hurricane, UT
(Click on the pics Below to Enlarge)

As a fulltimer, there are days when life is not all blue skies, hiking, and visiting with friends or new locations.  Sometimes we have to slow down and take care of the “day to day” maintenance items.

This blog is about one of those days. We’ve recently (well not really, it’s been at least a month) noticed that after flushing our toilet the water fails to stay in the bowl. After a bit of research on the internet  I was fairly certain that I knew the reason why. Time for a bit of maintenance.

To set the stage, we have the Thetford Aqua Magic Style Plus toilet. It is a manual flushing toilet with the foot pedal in the front. (NOTE: The Thetford Aqua Magic Style II is very similar to the maintenance procedure to be described below.) Our toilet  is original to our 2010 Tiffin Phaeton and has obviously seen much use through the years, as we live in our rig 365 days a year.

The model #34421 can be located on a label on the rear of the toilet.

My research suggested that it was time to change the waste ball seal. I had already attempted to clean the top and bottom of this seal (wear gloves for that one!), but eventually the water would still find its’ way out of the bowl. I went online and found the waste ball seal kit #34120 for my toilet. Since I buy a lot of stuff from Amazon, I purchased it online for $14.20.

Here is a picture of the items included in this kit. You'll get: Thetford instructions, 4 nylon thin washers, a closet seal, and a ball valve seal (bottom left).

The remainder of this blog will show what’s involved with the replacement of the seal. I am writing this from the standpoint of someone who has never removed their toilet from the floor and who has no prior experience with a repair such as this.       So let's get started.........................

At the end of the blog I will include a link to the .pdf version of Thetford’s instructions, along with a complete list of part numbers and costs for this job.

Slip Joint Pliers
½ inch Open End Wrench
½ inch Standard and Deep (Optional) Sockets
Phillips Screwdriver

Plenty of paper towels
An old cotton rag                Small container (such as a flat pan or cup) to catch water
Rubber gloves

Although I believe that a subsequent repair of this seal could be done without totally removing the toilet from the floor, I believe that most will find it much easier to work with the toilet in an open space the first time.

    1.       Shut off water supply to rig.

2  Depress foot pedal to drain all water out of bowl.

3. This toilet has a plastic shroud which is attached at the rear by  large and small rubber bands.To remove the shroud look behind the toilet and remove the two bands. 

4. Press down on the foot pedal while pulling up and forward on the shroud.

5. Disconnect the water supply line from the plastic fitting at the rear of the toilet. (Have a cloth or container on hand to catch water which will drain out of the valve.)

6. Loosen the floor bolts (one on each side) which hold the toilet base to the floor. There might be white caps covering these bolts, but I removed these on a previous repair job. These are 1/2" nuts and can be removed using an open-end wrench, but a 1/2" deep socket is somewhat quicker. Set the nuts aside as they will be used to re-install the toilet.

7. The toilet can now be lifted straight up and positioned in a more suitable work space. (Outside is good.) Be prepared to stuff old rags or paper towels into the sewer drain hole to prevent the escape of gases into the rig.

8. Because you will be separating the upper bowl from the base, I found it useful to disconnect the vinyl tubing from the aerator. (I forgot to list needle nosed pliers in the tool list at the beginning, but channel locks will also work here.)

9. To separate the upper bowl from the base, you will need to remove 1/2" nuts from each side of the mid-toilet area. There are two nuts to remove on each side of the toilet.

10. You will notice that the bolt threads are fairly short above the nuts, so a 1/2" open-ended wrench or a 1/2" socket works well here.

11. Please take note of the position of the nylon and metal washers on the bolt. When re-installed the nylon washers MUST be placed against the china bowl, then the metal washers are placed against the nut.  IMPORTANT! Do not overtighten these nuts when re-assembling the toilet.

12. Lift the upper half of the toilet straight off the bolts. (The bolts have metal retainers which will hold them in an upright position.) Place the upper half on a protected surface. Here's the seal which is to be replaced.  With your gloved hand, pull the old seal from the base and discard.

13. Flip the base upside down and remove the old floor seal and discard.

14. With everything apart, now is a great time to thoroughly clean the toilet.  

15. Although the Thetford instructions do not address this, I coated the top and bottom of the new waste ball seal, and the top of the plastic waste ball itself , with plumber's grease.

16. Make certain to place the "green" side of the new seal down against the base. Here's a look at it all "greased up" and in position.

17.It's time for re-assembly and re-installation of the toilet in the rig.  ADDENDUM FROM THETFORD HERE!!: Place the four new nylon washers onto the four vertical studs before placing the upper bowl onto the lower half. Raise the top bowl portion and place it directly over the four studs which are still standing vertical from the lower half of the toilet. IMPORTANT! Make certain that the top half is centered. When you look down into the bowl you should see an equal portion of the new seal showing all around. If not, lift the upper section and re-position. The view from above should look like this.

18. Place the old nylon washer over each stud, then place the metal washer above the nylon washer. Re-tighten each nut equally (alternating sides is a good idea).  Snug the nuts down, but DO NOT overtighten. You could crack the bowl with too much pressure.

19. Re-attach the vinyl tube removed in Step #8 above.

20. Place the new floor gasket onto the bottom of the toilet (the one removed in Step #13 above).

21.Take the entire assembled toilet back into the bathroom and carefully lower it onto the two floor closet bolts. (See Step #6 above). This was the hardest part of the entire repair job for me. It helps to have a second person to align the bolts as the toilet is lowered onto them.

22. NOTE: At this point, the toilet will not sit flat and flush to the floor. Don't panic. Carefully re-install the nuts on each floor closet bolt and tighten each side in an alternating motion. As the nuts are tightened the toilet will sit flush on the floor.  NOTE: Be careful again here!  DO NOT overtighten these nuts.  Snug is fine!

23. Re-attach the water inlet line to the rear of the toilet.  Hand tighten only.

24. Turn on the water supply and check for any leaks.  Flush the toilet with the foot pedal. The addition of the plumber's grease certainly made my toilet operate much smoother.

25. Re-install the plastic shroud removed in Steps #3 and #4 above.

THAT'S IT!!!!!!!!!!      YOU'RE DONE!!!!!!!!     JOB WELL DONE!!!!!!!!!!


Here is the breakdown of the costs involved in this project:

Thetford Waste Ball Seal Kit (Part #34120)          $14.20 from Amazon
Plumber's Grease (Home Depot, Lowes, etc.)       $2.49

Here's the .pdf version of Thetford's Instructions for this repair job.

Should you have any questions, please contact me either via the email link or via the comment section below.

Thanks for stopping by to take a look!


  1. Nicely done Steve. I like how clear your step-by-step instructions are.

    1. Thanks Randy. I use my blog as a reference when I have to do repairs in the future, so I attempt and make them simple for me to understand.

  2. You are very handy... you made an unpleasant job seem easy to do with your step by step instructions. Glad you are up & running again!

  3. Oh yeah ... we’ve had that problem of the water not remaining in the bowl as well. Mui had to do the same replacement work. And then a year or so later, the pedal gave out, so we replaced the whole kit and caboodle then.

    1. Erin I thought about replacing the entire toilet this time around. Which make and model did you guys go with as a replacement?

  4. Always good to have a successful repair

  5. Memories, memories. I've done this a couple of times too. A quick fix until a proper repair is done is to coat the ball and seal while the toilet is emptied of water with vaseline. This can last several months until time/parts are available.

    Excellent write up, I hope to never have to do this again! :cD

    1. Yes Paul, I've heard of the "vaseline" trick as well, but you, of all people, should know that a petroleum based product is not good for rubber seals.

    2. Yup, you're correct, but sometimes desperate times call for desperate measures! :cD

  6. Yep been there done that... good details on how to do it