Toilet cistern constanly filling

[ipbr21054]

Morning,
My neighbout has advised me that his toilet is just constanly filling.
Ive had a look & supplied cistern photos for you.

The water comes in the inlet like normal but i dont see what actually stops when required.
Ive removed the red sea saw bar which is connected to the float.
I then twisted the white cap on the top & inside is a black rubber seal with lets say serated fins going around.
Where the seal touches the plastoc is also serated fins.
You would think the red sea saw would move dependant on water level by the float & push the black seal to make contact & shut the water off but this doesnt happen,reason being where the red part connects to the white part nothing moves up or down, its just a pivot point.

So im lost as when the black float rises to the level how is the balck seal then supposed to make contact & stop the water.

The underside of the black float is a long red bar for water level height in cistern i assume & this doesnt do anything to stopping the water.

Can you advise please.
Thanks

 

[opps]

I an mot a plumber but under the white cap, I suspect that there is a rubber diaphragm with a pin that needs replacing.

Something like this

Plumbsure Rubber Float valve Diaphragm, (D) 25mm | DIY at B&Q

Plumbsure Rubber Float valve Diaphragm, (D) 25mm - B&Q for all your home and garden supplies and advice on all the latest DIY trends

www.diy.com

 

[ETAF]

something like

1:20 ish

2.20 ish

 

[ipbr21054]

Ok
Thats looks kind of like the seal i have.
I will take it out & clean it.

Can you advise how or what moves the seal so it shuts the water off.

Nothing i see connects with it to allow it to make its seal

 

[opps]

As the black float lifts the red lever pushes down against the diaphragm and pin to stop the water. You may get lucky and be able to just clean it but sometimes they split or deform and need replacing. I would wipe a little bit of silicone grease on it when replacing it.

 

[ipbr21054]

Ive taken it apart again and cleaned the rubber black seal.
The little pin that moves up / down in the seal.
There is also a small hole in the white plastic cap which is below where the red sea saw arm pivits.I can see through this fine.

Ive put it back together & its 99% better but still a dribble coming out the white tube which says the seal is soft or isnt sealing correctly.

What do you think

 

[opps]

Ive taken it apart again and cleaned the rubber black seal.
The little pin that moves up / down in the seal.
There is also a small hole in the white plastic cap which is below where the red sea saw arm pivits.I can see through this fine.

Ive put it back together & its 99% better but still a dribble coming out the white tube which says the seal is soft or isnt sealing correctly.

What do you think

Just get a new diaphragm. Take it to a local plumber's merchant and they will match it for you.

 

[ipbr21054]

Ok great thanks