I only have info on bench type toilets C2,C3,C4 on repairing/replacing pumps. All others [swivel bowls etc]
www.thetford-europe.com even if in Australia this europe site gives better download listing.
go in select English Select Customer Service.
Select User information on right of pic Select repair instructions. select buit in toilets. then select for your model. You can then download all information you want in the list.
I would send you some info on the C2/3 or 4 but am away tomorrow and wouldn't be here to send it for few days so the site is you best bet.
However if the C2 and you can wait untill Monday then send email to robertwhiting76@hotmail.com I'll send repair/replacement pump instructions I've compiled to a folder.
Bob
March 2009