Caravan DIY: How to Replace Toilet Cassette Seal?
The rubber seal on your toilet cassette will deteriorate over time so replacing it will prevent nasty leaks and smells.
Cassette toilets are pretty simple devices. The bowl receives the waste, and it is then stored in a little holding tank underneath. In between the bowl and the tank is a sliding disc known as a ‘blade’ that you can open and close. The blade is opened by operating a simple lever when you do your thing and then closed off the rest of the time. Closing the blade is critical because it prevents odours escaping from the tank into the van. The blade also prevents contents from leaking when wheeling the cassette to the dump point. The blade has a rubber lip seal which creates this odour and leakproof barrier.
Over time the rubber deteriorates, and the seal is compromised. You will get a pretty strong clue if smells start to waft from your bathroom. You can also do a simple test by closing the blade and pouring water into the bowl. If water leaks out of the bowl into the tank it is a good indicator the seal is compromised.
There are a variety of cassette toilets available on the market. Our friends at the RV Repair Centre step us through a particular Thetford model which will provide a general guide. Referring to the instructions for your particular make and model is important to get it right.
Obviously, this job is not to everyone’s liking and the internal mechanisms require a little bit of mechanical aptitude to put all the bits back together correctly. But it is definitely in the scope of your practical caravanner who has come to grips with emptying a cassette at a dump point is part of caravanning life.
Step-by-step Guide:
1. Remove the cassette toilet and thoroughly clean and sanitise as per normal
2. Remove the sliding cover from the holding tank plate
3. Place the sliding cover in the other side of the holding tank plate
4. Using the sliding cover as a lever, gently turn the holding tank plate anti-clockwise until it stops
5. Remove the complete holding tank plate
6. Turn the holding tank plate over and inspect for debris
7. Wash the holding tank plate with running water
8. Place the holding tank plate on a bench and remove the screw from the blade
9. Turn the blade track away so the opening is fully exposed
10. Remove the screws holding the support track in place
11. Remove the support track
12. Remove the screw holding the lip seal plate in place
13. Remove the lip seal plate
14. Remove the old seal from the lip seal plate
15. Wash the lip seal plate in running water
16. Use a manufacturer’s recommended lubricant on the new seal and place it in the lip seal plate
17. Reinstall the lip seal plate
18. Reinstall the lip seal plate screws
19. Swing the blade back over the opening
20. Reinstall the screw from the blade
21. Reinstall the support track
22. Reinstall the blade retainer screws
23. Check that the blade can swing freely
24. Reinsert the holding tank plate in the cassette in the diagonal position
25. Insert the sliding plate into the ‘lever’ end of the holding tank plate
26. Use the sliding cover to turn the holding tank plate clockwise
27. Remove the sliding cover
28. Check the operation of the blade again by turning the knob
29. Reinsert the sliding cover in its normal position
30. Reinsert the cassette in the van
31. Check the cassette blade operates correctly by operating the toilet lever
IF IN DOUBT, CONSULT A PROFESSIONAL
Improper maintenance can lead to injury, death or property damage. Maintenance work of this nature should only be undertaken by people with suitable competence. Information provided is general in nature, not comprehensive and should only be taken as a guide. Individual discretion must be exercised and persons undertaking described tasks do so completely at their own risk. Publishers and creators of this content accept no responsibility for loss or damage.
Thanks to Andrew Phillips and the team from the RV Repair Centre for their assistance.