Leaking Dudley Niagara Valve

[ooch]

I have a dudley niagara valve fitted to my toilet that has started to leak. Does anybody know how I can stop this. The silicon seal at the bottom mustn't be forming a water tight seal anymore. There doesn't look to be any damage . Should I just buy a new assembly or can I seal it in some way?

Thanks in advance

 

[seco services]

the rubber seal at the bottom you mean. clean the washer of any scale.
sometimes they start turning up at the sides remove and turn washer upside down and replace