How can I fix a leak in a flexible hose?

[Ben S]

A small leak on the join below the nut of the a flexi hose has developed in area indicated by the arrow. By "small leak" I mean it's occasionally slightly damp to touch, with maybe a couple drops of water overnight.

First thought was to replace it - the top nut connected to the cistern moves freely, but the bottom one connected to the copper piping does not want to budge. It's probably seized and I don't have the confidence to mess with it.

It looks like a small amount of PTFE tape has been previously applied. Can I get away with a little more or plumbers compound?

 

[Rodders53]

Undo the top nut connected to plastic cistern inlet.
Remove the damaged/worn (or missing) fibre tap washer and replace with a new one.
Re-tighten the nut carefully.
Should be no need for any PTFE tape on that screw thread connection (imho).

 

[Hugh Jaleak]

No such thing as a seized nut, they all come undone at some point, just depends on the method used to undo them. Top, if it's moving 'freely' then ensure it is tight enough in the first instance, there is (should be) a washer in there that makes the seal. Its onto a plastic thread though, so be very careful, it can cross or strip the thread very easily, and you'll then need a new Fill Valve assembly.

Bottom nut should come undone with a big enough spanner but you must support the pipework and hold the fitting with a second suitable spanner to ensure it cannot move. Quite possible it has been overtightened previously, so be prepared to cut the end ff and make a new joint below the existing.

Do not use any type of jointing compound on plastic, it isn't needed on this type of joint either if joint is made correctly. The washer is all that is required.