Thetford C250 cassette problem

[Pablo1]

Over the last couple of outings I have noticed that there is a leakage problem with our toilet cassette. When I remove it, the recess in the housing is filling with waste water. This appears to be coming from the slide assembly on top of the cassette. Does this sound like a new lip seal is required? Are they difficult to fit? I have removed the slider and can see a seal, but no screws to release, so has the seal to be "dug" out then the new seal pressed into place? By the way, this is one on the cassettes with wheels and a large circular section on top. Any help or advice would be gratefully accepted.

 

[Sproket]

Hello Pablo

have a look at this video 😉

 

[Pablo1]

Thanks Sprocket. Had seen this video. Unfortunately mine is a latter model cassette and looks different on top. The slides that JW removes are integral on mine. Think it may be more complex on this type........unfortunately!

 

[Sproket]

Have a look here at the Thetford C250 repair instructions...

 

[Dustydog]

Pablo
you have the same toilet as me. Orange wheels and grey plastic with a handle that extends allowing easy pulling.
My internal mechanism failed a couple of years ago causing similar problems.
If you look very closely at the main internal tank seal flap it rotates and rises thus pressing on the large rubber ring seal.

Mine failed. Plastic bits broke. It ceased to rise but did not rotate. This no water tight seal. Very easy to open up the mechanism. It just twists off. Will be stiff to start with. Spares are freely available.
Good luck.

 

[JTQ]

In use I would avoid "water" standing in the bowl, ie use with main flap open. Whilst the seal "should" hold water in the bowl, to do so without leaking does require a good supple seal.

 

[DeliDave_]

I think there was a sealing issue with these which the fix involved thin plastic shims fitting at the base of the tank with adhesive to push the seal tighter.May be worth ring Thetford and seeing if it is applicable to yours

 

[Dustydog]

I think there was a sealing issue with these which the fix involved thin plastic shims fitting at the base of the tank with adhesive to push the seal tighter.May be worth ring Thetford and seeing if it is applicable to yours

Sir Deli Dave
Yes. There were some mutterings about this point.
As far as I know a number of mechanisms failed prematurely. Mine failed last year. It was the plastic "bits" in the mechanism. The flap no longer rose to compress against the rubber O ring seal.
I was lucky. Got a second hand one, hardly used for £20.
The original unit had split. Yuk.

 

[DeliDave_]

You should get a double BAR sorting that out

 

[DeliDave_]

Watched videos and took mine apart to check it and gave it a good clean and lubrication,much smoother now.Thanks both