Rejoining toilet water supply to new inlet valve

[DRY411S]

In order to replace a syphon diaphragm, on a toilet where the cistern 'sits' directly on the toilet basin rather than by plastic pipe, I've had to completely remove the cistern, which has involved disconnecting overflow and water supply too.

I cannot get a watertight seal again between the water supply (copper) and inlet valve (plastic). The washer in the metal connection is in place.

What am I doing wrong?

THanks in advance for any replies to this noob.

 

[muggles]

Did you replace the washer in the connector, or try to reuse the old one? Are you certain you've not cross-threaded it?

 

[leakydave]

Sometimes the plastic thread gets worn and you cannot get a decent connection. If this is the case fit a newer style valve by Fluidmaster, that has a brass threaded shank to connect to. Fluidmaster own Oppella now I believe and Torbeck valves are also available with a brass shank. Have a look at the room available inside your cistern as a Fluidmaster will not fit every cistern due to either lack of space or the inlet hole is too close to the edge of the cistern. Good luck, 'quick jobs' like this often end up being a far longer affair.

 

[DRY411S]

Did you replace the washer in the connector, or try to reuse the old one? Are you certain you've not cross-threaded it?

No, and Yes.

Sometimes the plastic thread gets worn and you cannot get a decent connection. <snip>

Actually it is a new Fluidmaster syphon and valve. No idea why I said it was the old inlet valve. Regrettably it's plastic, no brass fitting. (And it is a tight fit)

 

[Hugh Jaleak]

Change the fibre washer would be the first thing to try. Often they're compressed when originally fitted and once disturbed wont seal again. As said though, do the nut up with extreme care, it is very easy to cross thread the plastic tail, and if you do that, the valve is scrap.

 

[oilboffin]

I usually leave the fill valve loose so the parts line up,thenwhen all connected I finally tighten.