Leak below sink waste

[hammonchees]

Hi all

This is very basic but driving me crazy - any help would be much appreciated.

As you can see in the attached photo, the sink basket strainer in my flat developed a leak and needed to be replaced, which I have done (old one shown in the photo). The locking pin assembly had become corroded meaning it would no longer tighten.

Anyway, that has been replaced fine and now there is no leak from the basket waste itself. However, water now leaks from the coupling between that and the pipe (shown).

I noticed when replacing the basket strainer that the coupling seemed a bit odd. The basket outlet appears to be the same diameter (40mm) as the pipe, although the pipe has a slightly flanged edge so the sharper edge of the basket waste sits against it. The only other component is a rather thin black rubber O-ring, slightly smaller than the pipe diameter, which was sitting loose on top of the flanged end of the pipe when I disconnected it. That suggests it was being used as a washer creating a seal between the two pipes but I struggle to see how as it’s so thin, so wonder whether it was supposed to be around the pipe (under the screw nut) as a seal there instead.

Unfortunately I don’t have a picture of the coupling itself and can’t get one for a while as I’m away from the flat.

Basically I just want to have a plan of action for fixing this when I next go. Is it a case of buying a flat washer to sit between the basket outlet and the pipe, or do you think that existing O-ring should be in a different place (i.e. as I’ve described above) instead?

The bit that’s puzzling me is that there was no leak from here before, so if the O-ring was being used incorrectly it didn’t make a difference!

Many thanks in advance.

35B24F4D-0FE4-46A1-9A95-3AF7632F3507

• hammonchees
• 19 Oct 2020

 

[sxturbo]

I use fernox ls-x on all the sealing faces, never had a leak.

Did you use any sealant?

 

[hammonchees]

Thanks for your reply - will check it out. No, sealant isn’t used anywhere at the moment.

 

[terryplumb]

The rubber washer makes the seal ,it has to be in contact with the bottom of the threaded waste. Show us a pic ,there are more than one type of washer.

 

[tel765]

Cant tell for sure but you seem to have the friction ring and the rubber washer the wrong way round. The fibre ring goes below the rubber washer. You've also re-used the old ring and washer instead of using new parts.
It will eventually leak so remove the whole strainer and break the waste connection and clean everything up using new washers. Then use plumbers putty to seal the basket plate to the sink and nip up the interior nut to pull everything tight. There's usually no need for Fernox sealant but use it if you want on sealing faces as described above.
That sink and waste are very poor quality and any of the the washers can distort under a bit of pressure.

 

[terryplumb]

Cant tell for sure but you seem to have the friction ring and the rubber washer the wrong way round. The fibre ring goes below the rubber washer. You've also re-used the old ring and washer instead of using new parts.
It will eventually leak so remove the whole strainer and break the waste connection and clean everything up using new washers. Then use plumbers putty to seal the basket plate to the sink and nip up the interior nut to pull everything tight. There's usually no need for Fernox sealant but use it if you want on sealing faces as described above.
That sink and waste are very poor quality and any of the the washers can distort under a bit of pressure.

The pic is the old one mate.

 

[tel765]

Sorry but I dont know what you mean. I can only see one pic are there more pics somewhere else?

 

[terryplumb]

No pic posted of the new fitting that leaks. Only the one you can see ,which is the old one before it was removed/ replaced.

 

[tel765]

Thanks mate, I can now see what you are saying. Its my fault, I didn't bother to fully read the original post and just jumped in. Thanks for setting me straight.

 

[hammonchees]

The rubber washer makes the seal ,it has to be in contact with the bottom of the threaded waste. Show us a pic ,there are more than one type of washer.

Thanks for your reply. Unfortunately I don’t yet have a photo of the exact one but it is very similar to the new pic I’ve attached. Although this is described as a washer I would have thought (albeit with no expertise) more of a flat-faced rubber ring would be better, to make good contact with the bottom of the threaded waste as you say.

Just not sure how it’s possible to get a good seal using the current one..!

 

[terryplumb]

Difficult to make out from pic ,appear to be " O" rings.( The cross sectional view of one being circular).
The most common ,by far, would be the flat faced type. So it's Cross sectional view would be rectangular.
But some trap washers are conical .
Whatever that was originally in your fitting needs to be matched.
Re using washers often results in leaks ,better to fit new .