I went to replace a faucet in the restroom sink. The existing lines where too short for the new faucet. I bought two new 1/2 in lines. Came home connected to faucet, then it didn't connect to valve. Went back to the hardware store and they told me the valves I have at home are 40 years old. I bought 2 new valves. I installed both exactly the same. The valve connected to the cold water is leaking at the connection from the pipe to the valve. I tried adding more teflon tape and same. I switched the two valves and the cold water pipe still leaks. Please tell me its an easy fix and that I don't have to change pipes behind the wall

Hello Clumpers,

Remove the angle valve check the pipe and the ferrule for crack or any sharp object if every thing is OK, install it per the images below, good luck.

John

Shouldn't be using Teflon tape if you are installing compression fittings... may be that is the issue... ;)