Newbie seeks advice on simple-looking leak

Discussion in 'Plumbing Forum, Professional & DIY Advice' started by larryleveen, Dec 10, 2012.

  1. larryleveen

    larryleveen New Member

    Messages:
    43
    Location:
    WA
    Found a leak under my bathroom sink. I think it is a simple one to fix, but would like some backup as I am a newbie at this.

    There was no moisture above the joint pictured (see below). You can see a water drop at the right hand side of a threaded section of pipe by a shutoff valve -- the handle is just out of the frame, but you can see the flexible supply line connection nut. Ignore the tilt of the picture -- it's the best I could do in a tight space.

    Anyway, it appears as though this is just a simple threaded joint. I removed the supply line and tried to tighten the (Brass Craft) valve onto the short stub of copper pipe, but I couldn't get it to budge. I was using a super short wrench, and I was kind of nervous to apply too much torque since I don't know what the h*ll I am doing -- it took several minutes for me just to figure out what kind of joint I was looking at. It seems as though I could just:

    - shut off the water supply to the house
    - open a hose spigot, which is lower than the joint in question
    - remove the supply line from the valve
    - remove the valve from the copper stub
    - clean the threads
    - apply a generous amount of pipe dope (maybe an insufficient amount was used originally?)
    - tighten the valve on again
    - close the valve
    - reattach supply line
    - close hose spigot
    - turn on water supply to the house
    - open up valve, try faucet & inspect the joint

    Is that right? what tools will I need? That is a super short stub of copper pipe to work with! Will I hurt the joint on the left where the copper stub goes into the 90-degree elbow when I do this?

    Any other advice is appreciated.

    leak.jpg
  2. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,143
    Location:
    South*East
    Replace the galvanized nipple with brass. You have a galvanized nipple between a brass valve and a brass fitting.

    John
  3. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,797
    Location:
    Cave Creek, Arizona
    That is NOT a "copper stub", it is steel nipple. Remove it and replace it with a brass one. I didn't realize there were so many steps to take in order to remove it. We just usually turn off the water, remove the valve, and replace it.
  4. jimbo

    jimbo Plumber

    Messages:
    8,997
    Location:
    San Diego
    For now, you could remove the line up to the faucet, and turn the valve another 1/2 turn onto the nipple. That might fix your leak.
  5. larryleveen

    larryleveen New Member

    Messages:
    43
    Location:
    WA
    Oh, I didn't know if it's OK to just tighten it more or if it breaks the seal that the pipe dope is (supposed to be) making.

    And of course the other responders were right that it is galvanized steel and not copper -- I had forgotten that I put a magnet to the nipple to determine that, duh.

    Are brass nipples like that a standard thing I could just walk into a hardware store and buy? Are they generally about that length? Why should I use brass?

    Is a pipe wrench the right tool to use to tighten the nipple (and to hold it motionless when tightening the valve on it)?

    Seriously, guys, I appreciate any detail you can give (hence my "long list" of steps).
  6. Terry

    Terry Administrator Staff Member

    Messages:
    15,110
    Location:
    Bothell, Washington
    You can use pliers or pipe wrenches. I do almost everything with pliers. I get a kick out of movies that show plumbers with giant pipe wrenches working on small fittings. sometimes on the wrong side of the fixture, the side with no plumbing.

    Brass is permanent. Galvanized steel will close up over time with rust. And placing steel between copper and brass just speeds up that process.
    Years ago I asked a plumber why the shop used galvanized.
    "It's a bit cheaper. Don't worry about it, it's a guaranteed service call later on."
    That was almost forty years ago.
    Last edited: Dec 11, 2012
  7. leejosepho

    leejosepho DIY scratch-pad engineer

    A "close nipple" is the shortest, and some will have flats for applying a wrench between the threaded ends. Wherever possible, it can be best to use a nipple you can tighten into one fitting before attaching the next rather than just putting all three together and tightening both connections from one end. And along with that, using a nipple with some "grip room" in the center can help make it possible to later remove that nipple without damaging its threads.
    Last edited: Dec 11, 2012
  8. kreemoweet

    kreemoweet New Member

    Messages:
    371
    Location:
    Seattle. WA
    That shutoff valve looks suspiciously thin where the female pipe threads are supposed to be. I wouldn't trust a valve like that not to split when tightened down.
    For sure, I would remove the valve, clean the threads thoroughly, and inspect closely.
  9. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,797
    Location:
    Cave Creek, Arizona
    You do NOT tighten the nipple into the valve. You apply sealing compoud to both threads then screw it slightly into the elbow, then screw the valve onto the nipple, THEN tighten the valve which will also tighten the nipple into the elbow. Pipe wrench, adjustable "Crescent" wrench, or pliers, whichever you have the strength to use will do the tightening. The nipple you have is 1 1/2" long, also called a "shoulder nipple" and they will have a brass one the same length. Oh, I, and many if not most, plumbers would change the other one at the same time.
    Last edited: Dec 12, 2012
  10. jadnashua

    jadnashua Retired Defense Industry Engineer xxx

    Messages:
    22,126
    Location:
    New England
    You do not really want any steel/iron in your supply lines. You may have used it because you were scared to try to solder things, but there are other choices that are essentially permanent, iron/steel is not. And, eventually when it starts to rust, you'll have rust streams in the sink or wherever that supply runs to.
  11. larryleveen

    larryleveen New Member

    Messages:
    43
    Location:
    WA
    Well, I took the stop off and cleaned the threads of the steel nipple and wrapped them with teflon tape. When I looked in the female threaded end of the stop I saw some debris, which I realized was the end of the nipple that had crumbled. I hadn't noticed when I was cleaning and taping -- or maybe it was "wishful non-seeing" it. I put the stop back on anyway, and the supply line, but it leaks still -- possibly slightly more now. Looks like I have to replace the nipple. photo-1.jpg
  12. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,797
    Location:
    Cave Creek, Arizona
    quote; Looks like I have to replace the nipple.

    That is what we told you to do from the start, but you may also have to replace the valve. I would NEVER remove one of those valves and then actually reuse it. That would usually be a waste of time.
  13. johnjh2o1

    johnjh2o1 Plumbing Contractor for 49 years

    Messages:
    1,143
    Location:
    South*East
    I just don't understand why people take the time to find and post a question on forums and then don't take the advice they spent the time looking for.

    John
  14. larryleveen

    larryleveen New Member

    Messages:
    43
    Location:
    WA
    Whoa there, guys. Don't jump down my throat here -- there's no call to be rude.

    I was advised by someone in the thread that I could just try to tighten the fitting. I figured that removing the pipe dope and teflon taping would be important. Nobody ever advised that the valve should be replaced before HJ _just_ mentioned it -- what's the problem with reuse or a brass valve, BTW? I am genuinely curious.

    My slow exploratory work was to "get the lay of the land" with something I am completely unfamiliar with. The fact that I didn't _yet_ replace the nipple doesn't mean I am ignoring advice. Also, not everyone has a work schedule or transportation situation that allows them to hit a hardware store after work. I'd never criticize you for proceeding slowly on a repair related to my field of expertise. Please don't take my slow pace as disrespect, and please be kind and patient with others. Thanks to all who have provided help. I truly appreciate it.
  15. leejosepho

    leejosepho DIY scratch-pad engineer

    The brass one should do better, but there can be complications even there. Not all manufacturers use the same process for making all the parts, and I have had times when one brand of nipple and another brand of fitting just did not fit together well at all. Also, pipe dope and teflon tape are actually more for reduction of friction during assembly so the parts can mate well than for sealing...and the same principle appears in electrical and electronics work where wire nuts and solder merely maintain a solid mechanical connection. So, always only use plumbing parts that fit well, and then use something slippery while fitting them well!
    Last edited: Dec 13, 2012
  16. hj

    hj Moderator & Master Plumber Staff Member

    Messages:
    26,797
    Location:
    Cave Creek, Arizona
    The reason for replacing the valve once it is removed, is that they have a "finite" lifespan, which means it will eventually have to be replaced and it would be easier to do it now than later. In addition, the leak could have been caused by the valve failing, not the nipple since it looks in good shape, so replacing the nipple, which SHOULD be done anyway, may not cure the problem. And, at my rates, the customer does not want to pay me for reinstalling the valve, then taking it apart and redoing it with a new valve. I would think that in the 5 days since you posted the question, you would have passed by "some kind" of store, (whether going to or from work), where you could buy the required nipple to try it with the old valve. It IS a simple leak, not just a "simple looking" one, which is why some are questioning why it has developed into a 2 page string.
    Last edited: Dec 14, 2012
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