Water shut off doesn't shut off.

[EThorn]

Hi all. I'm trying to replace a sink faucet and I found that the water shutoff under it doesn't fully shut off the water. It's probably possible to replace the sink as it's a trickle but just in case I run into difficulties I don't want to be stuck replacing pots under there or have to shut the entire house's water off. When I try to search online everything seems to be about the shutoff valve itself leaking rather than just not closing. I've tried tightening the knob (obviously) as well as the nut which seems to be tight.

I'm sure this isn't rocket science but can anyone tell me or point me to instructions on how to fix this up I'd appreciate. Here's a photo of the fixture:

 

[wood4d]

You need to shut off the house and you can replace the the compression shutoff. There are no shortcuts. The new valve is only $10

 

[Jeff Handy]

Change both valves.

You will be opening and closing them both several times during your faucet replacement.

The valves are equally old, so the other one will likely start to leak or not shut off either.

After you change the valves, run some water from each new valve right into a bucket, to clear out any loose junk or minerals.
Otherwise, they will clog up the aerator or flow restrictor of the new faucet.

 

[TomFOhio]

Buy quarter turn valves as you won't be sorry.

 

[Zanne]

Change both valves.

You will be opening and closing them both several times during your faucet replacement.

The valves are equally old, so the other one will likely start to leak or not shut off either.

After you change the valves, run some water from each new valve right into a bucket, to clear out any loose junk or minerals.
Otherwise, they will clog up the aerator or flow restrictor of the new faucet.

The bolded part is critical. I was helping a friend with his plumbing and told him to flush his lines into a bucket before hooking them up but he didn't listen and the gunk completely clogged up his faucet to the point it no longer worked at all. (It was an old one that sucked anyway-- he got a better one after that).

 

[EThorn]

Quarter turn valves, got it.

It looks like they are using compression nuts... correct? I feel like I should be capable of that job (soldering I'd likely just call someone).

Am I correct that the shutoff valves are standardized to 1/2 for the connection to the input pipe? My new faucet has 3/8 water lines for the output so I know that one.

 

[Jeff Handy]

Your pics of the valves are not great, but it looks like you do have 1/2 inch compression type valves on 1/2 inch copper pipe.

So any new valves of that type should be ok for replacement.

Just a suggestion in future, take a few more pics from different angles.
And take several pics of the same thing, and keep the best one.

 

[Riickk]

What are people here doing with the compression nut and ring.
Keeping & re-using the old one, or using a tool to remove the ring?

 

[TomFOhio]

If the nut and ferrule are good then reuse it. If not, then there is a tool to remove it. If the copper sticks out
far enough then you can cut the old nut and ferrule off and use the new. Just make sure you have enough
room for the new.

 

[breplum]

I have always re-used the nut and ferrule with no recollection of any problems.
Other plumbers differ on that opinion, though.

 

[Jeff Handy]

I always try to re-use the old nut and ferrule also, but it’s important to clean it up first, to get minerals or crud off of the ring and out of the threads of the nut.

Clean with a little vinegar or even just water, and use a plastic scrubbing pad like a Scotchbrite.
Maybe it’s overkill, but it beats a callback for a slow dripping leak.

Sometimes, if the old brass ferrule or the threads of the nut are slightly corroded, I put on an extremely thin coat of teflon pipe dope on both parts.
The lubrication helps the old rough threads of the nut tighten down easier, and I think the lubrication helps the brass ferrule squish in tighter against the new valve.
Maybe this is wrong, but it’s how I do it.

 

[EThorn]

Just wanted to update, thanks everyone it was a pretty easy job. Turns out the ferrules just came right off with a little coaxing without having to cut them or use a tool and nothing leaks (yet). At least now I can work on the faucet without worrying about turning off the master water valve!