Toilet inlet, won't seal

20 Jun 2016
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United Kingdom

I have a Fluidmaster Bottom-Entry Fill Valve ½"
It's been in a couple of years with no problems but recently started to leak - Im' not sure if the original leak was from the water in the cistern or the mains water in the 1/2 BSP fitting but now I can't get the 1/2 BSP connection to seal.

It was connected with a right angle copper 1/2BSP to 15mm solder fitting with a fibre washer, a short bit of copper pipe and then a 15mm to 15mm compression flexy hose.

The right angle and short flexy made access a bit of a pain as it is a concealed type toilet and I decided to put a longer flexy direct to the inlet.
I got one of these:

I can't get it to seal!

I noticed that the new flexy 1/2" BSP has a much smaller inside diam ridge/rubber washer vs the copper fitting has a much larger diam inner spigot so the fibre washer is much narrower and has less room to move.

The end of the inlet is very thin walled and I think it is failing to clamp the washer so the washer is squishing out of the way.

Seeking advice on getting it to seal.
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The link to the Flexi shows a 3/4 BSP ,I assume you are not using that ,but a 1/2 inch BSP Flexi. Is the rubber seal/ washer too small in outer diameter ? It should fully touch the inner edge of the nut. If it doesn't ,fit a new one. I had this problem recently with screwfix's flexible hoses .The rubber washer is just TOO small in outer diameter.
Does your fill valve have a plastic threaded shank. If it has and its been cross threaded, it is probably knackered and will need to be replaced. Get the fluidmaster pro with the brass shank.
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Hi, thanks for the replies.

I guess I pasted the wrong link - yes it's the 1/2 BSP, plastic shank.

Terrypluimb, thats very interesting! I'll take a better look at the washer in the flexi hose.

The thread on the inlet looks OK but it does have some old black mastic on it that could be the issue - I have a spare of the fill valve I'l try.

I was wondering about getting the brass shank version instead.

The brass shanked one is better than plastic ,which are too easily cross threaded if your not careful.

Hope all well

I am in same problem I have

viva-bottom-entry-skylo-fill-valve-15mm no other washers inside or outside.

It seems to be dripping from the toilet tank, I am thinking to tight it with silicon sealant inside the tank.

Any advise would be highly appreciated.
viva-bottom-entry-skylo-fill-valve-15mm no other washers inside or outside.
There should be a rubber seal/washer inside the tank, to seal the valve to the tank base.

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