water shut off valve under sink is stuck

Hello all, Happy new year!
I have a shut off valve under one of the bathroom sinks. It is stuck. I tried to turn it back and forth slowly, but it only moves about a quarter turn. I did this for 10 minutes and it didn't move more than that. I am concerned that it may break if I exert more torque on the handle, because I don't really know whether it is close to fully open or fully closed.

I then thought since the valve is in a tight space, things may be easier if I remove the valve and deal with it on a table top. But, how do I remove the line that goes to the sink? (please see the picture). Thank you in advance!

You need to replace it.
Now that you turned it you better put a bowl under it and check it.
It just might start leaking.

If you can get the valve off including the back compression nut, then install a new valve.

Thank you Mr_David for responding.
Yes replacing it sounds like the only option.

But, in my case, there doesn't seem to be a nut where the supply line connects to the valve (please see the picture in the initial post), so how do I detach the supply line from the valve?

You don't it has to be disconnected from the sink. I would replace both hot and cold.

johnjh2o said:

You don't it has to be disconnected from the sink. I would replace both hot and cold.

Click to expand...

Not clear what you mean - there is an identical valve next to this one, and it works fine. I suppose the problematic one I am trying to deal with is for hot water since it is on my left hand side. Why do I need to replace both hot and cold, if the cold works fine? Thanks.

[ame="https://www.youtube.com/watch?v=SNKrBQCzQOI"]https://www.youtube.com/watch?v=SNKrBQCzQOI[/ame]

They were junk to start with and they don't improve with time. You have one that failed and the others are the same age. It's your call.

what John is saying, you WILL switch it out later. might as well do it now while you have the water off and tools out


would you only replace one break shoe on the front of your ride? same principle

johnjh2o said:

They were junk to start with and they don't improve with time. You have one that failed and the others are the same age. It's your call.

Click to expand...

Got it. Thanks. But, I still need some help - it looks like the sink supply line is welded onto the valve? how to I detach it? I've never seen a valve like this.

You disconnect it from were it connects to the fixture.

Just to clarify lion, yes, that particular supply line and valve is all one unit, and is "welded" together. They are junk, and will need to be replaced by a new supply line AND a new valve.

Thanks everybody. First post on this forum. Very helpful!

I also just found this on the web.
http://www.dummies.com/how-to/content/types-of-water-supply-lines-to-a-faucet.html

So what I have is the "factory-attached soft-copper supply line".