New stop tap connections leaking

So I installed some stop taps under my sink as I was installing a mixer tap to replace a conventional one. I thought it would be fairly easy, but I was very much mistaken! No matter what I do, they just keep dripping. A heap of teflon tape, very tight... leaks!

To explain the setup. The main connection to the water paper is a tapered brass fitting that plugs up against the rolled end. I had problems with this connection as well, though it seemed a bit better after I annealed the end. As for the other ones, just endless drips. Slow, but leaks. The connection from the tap has a rubber seal inside, so that behaves as well.... All the other connection are just regular screw ins. Any thoughts?

 

I added labeling to make the discussion easier.

A novel use for a shutoff valve. It looks like you're using the valve backwards from the way it was intended to be used. The B end of the valve looks like the outlet and the C end is the inlet.

I'd imagine the leak is at C as it doesn't look like the right adapter was used to match the flex line.

 

where is it leaking A B or C ?

 

Thank you for the replies. Backwards you say? I thought about it and figured this made more sense, though anyone knows better than me, was total guesswork. Well I can fix that when I try to sort it all out.

The flex hose side of C is the only place I consistently lack leaks. The valve side of C is pretty well behaved as well. It is at the join to the T piece I get all the leaks.A, B and lets call the plug on the left side of the T the letter D.

 

Could be a poorly made Tee. I have had to throw brand new fittings in the trash and buy replacements from a different source because they would drip no matter what. Threading is just poor quality on some foreign made fittings. If you can screw it in more than a quarter of the way by hand the threads may be bad.

 

I am able to screw all the way... I had no idea what to do anymore bar adding a lot more teflon tape, so that is what I did. Seemed to have fixed the problem. This is part of a one week reno job and was the finishing touch, so was frustrating, but so far so good. Thanks all!

 

Glad to hear that it's sealed up.

I'd imagine your issue was different types of fittings. Just because they are the same size, doesn't mean they will thread correctly.

You have a combination of FIP (iron pipe fittings) which are tapered and use teflon tape or paste to help make a good seal. There's also compression fittings which include a rubber washer on the inside of the female side. The threads don't seal, but the rubber washer does.

Keep this in mind if you put things like this together in the future!