Leak at supply valve

[JeffU]

First my apologies for this stupid newbie question.
I just replaced a 35 year old toilet with a new Eco Drake. A very simple install and great toilet.

I decided to replace the also 35 year old supply valve that would not completely shut off the water. I purchased a new Brass Craft valve, removed the old compression ferule and used a pipe cutter to get a nice clean new pipe edge. I cleaned the pipe with steel wool and used the suggested drop of oil on the threads of the compression nut.

The new brass ferrule seemed very loose when I installed it, but it seemed to tighten down and no leaks. 2 days later it has developed a very slight leak at the compression fitting. This leak is at the back of the supply valve from the wall, not the new flex line to the tank.

My stupid question is could I have not placed the compression ferule in the right position? I did a forum search and several threads indicated that the pipe needs to bottom out inside the valve. But will the valve push the ferrule in to the correct position? I tried re tightening the nut but am afraid of damaging the valve.

Thanks,
Jeff

 

[Jimbo]

The idea is that you have to keep pressure on the pipe so it stays bottomed out in the valve as you start to tighten. The ferrule will automatically be in the right place. The only problem comes is if the pipe pulls back before the ferrule takes a set, the forward side of the ferrule slips out over the stub end of the pipe and of course doesn't set up right.

At this point, if the valve basically feels snug and doesn't wiggle or twist when you grab it firmly, then I would apply 1/2 turn to the nut and see how that goes.