The only difference between c4,3 & 2 is the C2, has its own electric flush pump in the resevoir tank/flush tank accessable after removing the toilet roll holder housing, just prise it up out of hte tank. The C3, mostly in motorhomes ,is run from the main onboard water tank pum and is operated by an electric none return valve in the toilet unit. Finally the C4 is a manual pump which apparently can be changed to an electric one. All three waste holding tanks are basically the same, your problem may be the rubber seal needs replacing, and yes they are repairable that is the parts on the tank are all replaceable, no the tank does not come apart.. Hopefully you are reading this because if you haven't yet discovered already the Thetford site offers FREE pdf repair downloads follow the info below.
UK www.thetford-europe.com
Australia www.thetford.com.au (Even get request from Australian campers)
Australia site has stockist list.
HOME PAGE SELECT ENGLISH {if in Australia forget this selection)
NEXT PAGE SELECT CUSTOMER SERVICE (top line)
NEXT PAGE SELECT USER INFORMATION (left of pic) also 'Ask thetford' is on this page.
NEXT PAGE SELECT REPAIR INSTRUCTIONS (left of pic)
NEXT PAGE SELECT BUILT IN TOILETS [top right of pic]
NEXT PAGE SELECT This is where you select your toilet range. Search alll if unsure of type/range
NEXT PAGE PDF Files You should be in the pdf folder list on your Thetford toilet. Start downloading.
To direct link to the Thetford download site type in the following
www.thetford.eu/web/show/id=51498/langid=42
Don't bother for Thetford fridges they tell you for safety reason to take it to a service centre
Bob
September 2009
howtomendit.com for free repair help, information and advice.
Try fixfault.com to fix caravans/motorhomes.