Rear position change

(b) in the case of the following:

must change my tailband since the middle part is complete over.
now my question....the expansion I do not imagine so wild (hope there are only a few nuts that I have to solve from the inside ??? But it makes me feel sore.
can I use the old one or should I necessarily use new ones?
if so, where do I get them?

thanks to fpr your help.

Greetings
Jörg