this might help:- https://www.ducatiforum.co.uk/threads/so-this-rear-suspension-bolt-seized-mmmm.64852/#post-1191056
It's an M10 but is a special bolt with a longer head that fits snugly in the hole in the swinging arm. This snugness lies at the root of the problem with them seizing.
sorry, above thread doesn't actually state hex size, the hex size for an M10 would typically be 8mm but as it's a special then this needs confirming. If listed correctly:- Pt No 77159378B - M10x50x1.25
Sorry. I can confirm that the hex socket is indeed 8mm. You will need something like this to hopefully get it out. https://www.amazon.co.uk/KS-Tools-9...33&hvtargid=pla-420510119466&psc=1&th=1&psc=1
