Hi
I have an elderly 1988 ish sirocco with a manual Thetford toilet.
When I try to open the flap it is stiff and only opens about an inch, I have taken the seal housing apert, cleaned it, oiled it (olive oil) but it is still very stiff, I suspect the mechanism inside which you cannot get at because its a sealed unit.
I have scoured ther internet for a new holding tank complete but to no avail, I would appreciate any advice please.
I think it is a C4, iot is white in colour, the manual flush is on the right side and the flap opener is on the left whern looking down on the toilet from the inside if the bathroom.
Try taking the tank out and turn the blade opener while it's out, if it's still stiff remove the lip seal then see if it turns easily, you might need to replace the lip seal, they do tend to be a bit stiff to prevent them leaking when you take it out to empty it.
Use a silicone lubricant spray on it, if all else fails ring Thetford support they are very good and they may be able to source a new holding tank for you.
------------- Bill
For a licence dated 1997 or later you must add together the plated max weight of the caravan and trailer, if the total is 3500 or less you can tow it. You may even tow a caravan with a MAM greater than the cars unladen mass the restriction was removed in 2013