New Fluidmaster fill valve leaks

[Oldtownoak]

I just installed a new Fluidmaster 400A and there is a leak from the valve cap. Any ideas as to why this is happening? Surely, the seal isn’t bad on a brand new fill valve.

 

[Twowaxhack]

Yes, it could be defective. I’ve had many do that. Replace it again.

 

[Oldtownoak]

Thx…

 

[gagecalman]

Try Korky. I'm not a plumber but I like them.

 

[Geofd]

There is a rubbere disc under the black cap that's what cause issues with fluid master
Fill valves part# 242 just pop off the black top spin the arm that goes up and down to your left or right and you will see the disc tales less than 5 mins

 

[Twowaxhack]

I have a box full of 400a’s that when they fill the tank up and cut off, a few minutes or seconds later a little water will piss out from under the black cap.

They’re defective. Replace them

I’ve collected these defective ones over the past two years or so. I install about 15 a week.

 

[Geofd]

My old foreman from a long time ago made us change the discs before changing the whole fluid master, he was the same guy that made us rebuild, Chicago stems, and flushometers,and other rebuildable things
,To this day I won't install compete flushometer kits from Sloan,they are more money and I have the new people rebuild them just so they know how to,off topic but l
Was rambling

 

[Twowaxhack]

My old foreman from a long time ago made us change the discs before changing the whole fluid master, he was the same guy that made us rebuild, Chicago stems, and flushometers,and other rebuildable things
,To this day I won't install compete flushometer kits from Sloan,they are more money and I have the new people rebuild them just so they know how to,off topic but l
Was rambling

I don’t have a problem with replacing the seal but on a brand new fluidmaster that is giving the symptoms the OP is describing, changing the seal does nothing.

It’s a known defect to me on brand new 400a’s.

 

[Geofd]

I don’t have a problem with replacing the seal but on a brand new fluidmaster that is giving the symptoms the OP is describing, changing the seal does nothing.

It’s a known defect to me on brand new 400a’s.

Sounds good

 

[Twowaxhack]

Try Korky. I'm not a plumber but I like them.

You like that squeal they let out when they cut off at the end of the cycle ?