"Grunthos" wrote in message ...
"Ad" wrote in message
om...
Hello all,
Can anyone advise on a cistern that has a slow drip please?

I've only just replaced the whole cistern unit. The drip comes through
the thread of the pipe sticking out of the bottom (actually it's all
one piece with the internal mechanism. It was also leaking directly
under the cistern untill I put some evo-stick on there - so its a bit
better.

A previous post recomended Fernox Leak Sealant - is this the right
stuff? The evo-stick was recomended by my local plumbers merchant. I
also have some PVC glue.

(By the way the unit also had a leak at the join with the inlet pipe,
due to nut not threading properly. I managed to cure this by cutting
the pipe down a bit to remove a section with wonky thread, but is all
this kind of thing a common problem wth plastic joints?)

Anyhow thanks for any help,
Ad

Most plastic fittings recommend you don't use any form of additional sealant
on the joints; some sealants will attack and weaken the plastic.
If the cistern is leaking from the bottom, check the rubber washer (normally
fitted inside, not outside), also the nut shouldn't be too tight, if it is,
it can crack the plastic; it needs to be just tight enough to seal; if it
requires anything more than hand-tight, there's something wrong.

I may well get flamed for this, but, I often use a (very) small amount of
Vaseline on plastic fittings where there is a compressed rubber washer, it
helps with sealing and also makes it easier to remove should you have to in
the future.

HTH

John, yes it does have a washer. Maybe part of the problem is that the
whole internal mechanism leans a bit when handle is pulled - you can
see the bottom of the (plastic) cistern "wobble",maybe it opens it up
enough to leak a bit. The flush pipe wiggles too.

Alex, yes I did put the washer on the inside. I've put some silicone
sealer on now - mostly on outside as can't get decent acess inside
without taking it all off the wall and apart. I let it dry for about
five hours, then released the ballcock arm to put the water back on
and seems ok so far.

Grunthos, yes i might have overtightened it. (why don't they say in
the instructions - obviously i'm not a professional).

I think in future it might be better to assemble it as far as
possible, including the flush pipe, before fixing it to the wall,
whiile it is easy to fiddle with.

Thanks all,
Ad