GB wrote:

Andy Burns wrote:

https://www.cyberpieces.com/25457-large_default/joint-de-l-adoucisseur-d-eau-bosch-00166878.jpg

That's amazing. Well done for finding that.

A quick search didn't find 10x21x5.5mm o-rings, not sure if superglue
and some cord would work?

http://www.bearingshopuk.co.uk/5-5mm-nitrile-o-ring-cord/