Connecting 2 taps with Y connector

[Ashraf Hassan]

Hi All,
I have very strange case for the moment.
I have basin in the toilet.
This basin has one tap with inlet of 1/2" down the basin.
This tape was connected to water source of 3/8" outlet using the a non flexible pipe.
I want to connect the a new tap below the basin, so I did the following:
1) I got the following stuff:
a) 1 flexible metallic pipe of 50cm, one side is 3/8" and the other side is 1/2"
b) Y Connector
c) Another tap.
d) Teflon tap
2) I connected the 3/8" side of the flexible metallic pipe to water outlet using a teflon tap.
3) I connected the Y-Connector to old tap (below the basin) using teflon.
4) I connected the other side of the flexible metallic pipe to the Y connector using teflon tap.
5) I connected the new tap to the outlet of the Y connector using teflon tap.
The problem that when I open the water source, the water starts to drip in the Y connector from the old tap size, it seems that there is certain type of leak between the old tape, and Y connector only appears when the water is pushed upwards, how can I stop this dripping, as I tight it it very well.
Please help me in my question/
* All the pipes, and connectors are made of Steel

 

[Diyisfun]

Have you used the washer in the Y conector?
If yes, then you could try undoing the leaking thread, wrape ptfe tape found & re fit.. DO NOT OVER TIGHTEN

 

[Ashraf Hassan]

You mean a washing machin?
No I want to connect a peda to the other tap.
Do you think I have to use silicon?

 

[Ashraf Hassan]

Do you mean a metallic waher to put it around the screw of the old tap above the Y connector? do I need any rubber?

 

[Diyisfun]

I would expect the Y connector to have been supplied with 3 rubber washers, these are usually pre fitted

edit
Y connector would only come with 1 washer (femail end)

 

[Ashraf Hassan]

No it is only a metal, I have a rubber in the flexible pipe only