Fuel pump removal

This is a quite easy question, but I just couldn't do it...

I read I should use a screwdriver and hammer on the ring counterclockwise, however I hammered quite hard but nothing moves, I'm pretty sure I'm doing it right as I used the Haynes manual as a reference and the picture is quite clear. I think the whole thing is just too stuck, so I'm afraid I'll break something.

How would you proceed? Should the oring be changed? If so, is it available for purchase? Any other suggestions?

Regards

Im not sure a hammer and screwdriver are best here, but yes it was quite a apin in the arse when i did mine. If the oring is torn or just plain ugly then yes replace it, but it normally is good, just clean the thing up real good. If you have a strap wrench that will work better, and get you more force correctly applined to the whole plasztic nut thing your trying to get off.

Sounds reasonable; Ï'll give it a try, yesterday it was already dark so I left it for another day, let's see if I have time this week.

Regards