Slight leak after changing float valve

[smulx]

I was just hoping for a bit of advice. I recently had to change the float valve in my toilet and did it myself as it seemed quite straightforward. The old valve seemed to have been stuck in with sealant so it was quite hard to get out. I fitted the new valve but noticed a very slight leak underneath the cistern. I removed the new valve to investigate, and I think there's an issue with getting a good seal between the valve and cistern.

I took a picture of both sides of the cistern. Is it normal to have a rubber insert in the hole? At first I just thought it was sealant, but after I took the picture I could see a pattern on the bottom of it. Does it look as though I've damaged it and can it be replaced? Or is there anything else I should be checking?

Any advice would be appreciated. Thanks.

https://i.*********/TlZdxK0.jpg
Imgur

 

[rpm]

I`m thinking that was there when you removed the valve -Yes?
The new valve has a rubber washer against a shoulder -Yes?
You need to remove the old washer (Silicone) to get a good seal there.

 

[ShaunCorbs]

Agree with the above need to remove the old silicon

Time to get the Stanley blade and old chisel out

 

[rpm]

Agree with the above need to remove the old silicon

Time to get the Stanley blade and old chisel out

But not the hammer
OR Screwfix sell a little bottle of silicone remover.
Need to remove every last bobble of it or it may still leak.

 

[Harvest Fields]

Which inlet valve have you purchased?

 

[smulx]

Thanks everyone. I have some sealant remover already so I'll give it a try tomorrow. Seems silly now, but it's in quite a tight space and I didn't realise that the sealant was separate to the rubber around the hole.

This is the valve I bought - https://www.NoLinkingToThis/p/opella-bottom-entry-toilet-cistern-float-valve-part-3/52836

 

[rpm]

If you look at the picture in the link you can see the Black rubber seal, now some members will disagree with me but I apply a heavy smear of LSX sealent to mine and wipe the excess away before filling the cistern with water.

 

[Harvest Fields]

If you look at the picture in the link you can see the Black rubber seal, now some members will disagree with me but I apply a heavy smear of LSX sealent to mine and wipe the excess away before filling the cistern with water.

Shouldn’t need it to be honest though mate. Not once all the silicone has been scrapped away.

 

[rpm]

Shouldn’t need it to be honest though mate. Not once all the silicone has been scrapped away.

I agree "Shouldn`t" but after so many rough cast cisterns I just do it now regardless.

 

[gassafe]

Looks like you overtightened it! The ceramic is all breaking away!! New cistern time or a bodge with lots of silicone!!!

 

[Harvest Fields]

I’m sure there is no crack and it is just silicone mate.