grandadbaza Posted November 22, 2021 Share Posted November 22, 2021 I have a Thetford C250 toilet and everything has been fine until yesterday when we noticed it was getting very difficult to open the flap with the lever, it has become quite stiff to move, I removed the cassette and tried the lever inside and it was free, then tried the turn button on the cassette and that too was free, but when I replace the cassette, making sure it is fully pushed in , it is still quite stiff to operate with the lever, I even tried my spare cassette and that is just the same . Any thoughts or advice appreciated Link to comment Share on other sites More sharing options...
Tracker Posted November 22, 2021 Share Posted November 22, 2021 If the problem only exists when a cassette is fitted and is the same for two different cassettes it points to the internal mechanism having the issue not the cassette. The mechanism is only plastic so do be aware of forcing it and breaking something expensive, as well as the 'inconvenience' of being looless! First thing I would suspect - is the cassette fitting fully into it's housing slot with correct alignment? Do the chanels into which the cassette slots look sound and in alignment? Any chance the cassette could be snagging on something as you slide it in and that causes misalignment as it slides home? Could there be something, possibly something small or a distortion within the locker at the back of, or base of the locker, preventing the cassette opening knob fully engaging with it's slot in the opening handle or forcing the cassette to sit too high and taking away any free space needed to allow easy movement? I don't recall how much vertical end float there should be in the opening mechanism but if you lift the lever does it still turn OK? Apologies if you have checked all these, but long distance diagnosis is not my strong point!! Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 23, 2021 Share Posted November 23, 2021 Barry Thetford's repair instructions for their C250 cassette-toilet model can be found here. https://www.thetfordservicenet.com/wp-content/uploads/C250-Repair-Instructions.pdf You haven't said which C250 model your motorhome has, but the blade-opening mechanism is similar for all versions and there are exploded-view diagrams for C250S/CS/CWE variants here. https://www.leisurespares.co.uk/brands/thetford/toilets-thetford/c250-toilet-range This 2019 forum thread related to a Thetford C263 toilet 'jamming' https://forums.outandaboutlive.co.uk/forums/Motorhomes/Motorhome-Matters/Thetford-cassette-toilet-jamming/51055/ For opening/closing the blade-valve ('flap') at the base of the toilet-bowl, the C260 and C250 ranges use a similar mechanism comprising a toothed gear-ring attached to the opening/closing lever and a gear-wheel that engages with the gear-ring and operates the blade-valve. (see image attached below). As the opening/closing lever is stiff to move when the cassette is in place, I suggest you remove the cassette and (while operating the lever) give the toothed gear-ring and the gear-wheel a liberal spraying with a suitable lubricant. Thetford markets a seal lubricant that should be OK https://www.thetford-europe.com/gb/products/toilet-care-products/silicone-spray/seal-lubricant I'd use WD-40 Dry PTFE lubricant (because I have some and it works well) but any 'dry' silicone spray lubricant should do. I think your motorhome is 2010 vintage. You might want to remove the operating mechanism from each of your toilet cassettes and give all the moving bits a damn good clean. It's surprising how much crud builds up and, even though you've said that the cassettes' operating 'button' turns freely, cleaning (and silicone lubricating) the moving parts is bound to reduce friction. Link to comment Share on other sites More sharing options...
grandadbaza Posted November 23, 2021 Author Share Posted November 23, 2021 Thanks, Derek, Yes your correct we bought the M/H new in 2010, and have about a month ago replaced the Complete Holding Tank Mechanism in one cassette so I didn't think it was that, But I had tried using some Thetford seal lubricant and it made it a bit better yesterday,but today I have given all the moving parts that I can access and given them really good dowsing of the lubricant and it appears to have done the trick, just need to order some more Thetford lubricant now as I used all mine up :-S Thanks a lot for your help and valuable links Barry Link to comment Share on other sites More sharing options...
Derek Uzzell Posted November 23, 2021 Share Posted November 23, 2021 Good to hear that lubrication proved effective. This 2018 Caravan & Motorhome Talk forum thread discussed blade-opening issues with C250 toilets. https://www.caravantalk.co.uk/community/topic/132721-thetford-c250-blade-opener/ It's mentioned that the gear-ring and gear-wheel (image below) may 'jump' out of mesh if the blade-operating lever is moved while someone is perched on the toilet. Something to beware of perhaps... Link to comment Share on other sites More sharing options...
grandadbaza Posted November 24, 2021 Author Share Posted November 24, 2021 Derek Uzzell - 2021-11-23 5:28 PM Good to hear that lubrication proved effective. This 2018 Caravan & Motorhome Talk forum thread discussed blade-opening issues with C250 toilets. https://www.caravantalk.co.uk/community/topic/132721-thetford-c250-blade-opener/ It's mentioned that the gear-ring and gear-wheel (image below) may 'jump' out of mesh if the blade-operating lever is moved while someone is perched on the toilet. Something to beware of perhaps... Thanks again Derek , I will bookmark this post for future reference, my power of memory is not what it was :-D Link to comment Share on other sites More sharing options...
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