How to fix Leaking Sink Drains

411 plumb Probably one of the most common leaks in a home is a leaking sink drain. So yes, that awful mess under your kitchen sink or, vanity where the wood is all funky and rotted isn’t just happening at your home. You aren’t the only home that has some kind of pan sitting under there catching drips. Have you ever had the drain pipes under the sink just fall apart when you bump them putting something away under the sink? I have seen amazing ways off propping up drain pipes to prevent them from coming apart. Sometimes it’s a worn out or, rotted out pipe causing the problem but, most of the time it is just a bad installation. Not just DIYer’s handyman work is responsible for these leaks and loose drains, quite a few plumbers aren’t very good at installing tubular drains either. I will tell you some of the most common errors people make when hooking up tubular drains under a sink and how to avoid them so that your drain has no leaks and won’t fall apart if you look at it wrong.

Cross Sectional Drawing of a Slip Joint Connection

Cross Sectional Drawing of a Slip Joint Connection

To have a good drain installation you must first start with quality materials. This is not a debate about tubular plastic or, tubular brass as both are good materials and will serve you well. Instead it is to tell you about products often cleverly marketed as easy to use that are pure junk, if these parts are used will be the Achilles Heel of your drain. The infamous flex pipe or, flex trap which looks like and accordion and can be stretched or bent into various configurations is one of these products to avoid. Another is the flexible rubber trap with the two hose clamps that secure it in place. The flex connectors have a problem where debris can be caught in the accordion folds and give off horrible odors if used between the water seal of the p-trap and the sink drain. The problem with flexible connectors is the drain is connected rigidly at the sink drain and where the p-trap wall outlet connects at the wall, the pipes in between should have solid connections giving each piece of tubing used solid support from the two sides. This support is what makes the drain strong so it doesn’t fall apart. The flexible rubber traps also have a tendency to kink when not lined up well enough also. If you use either of these products your drain installation is doomed from the start, there is no substitute for doing it right.

Another common mistake is mixing components between plastic and metal. It is acceptable to transition from metal tubular to plastic tubular at a slip joint connection I try to avoid it except in the case of using metal basket strainer assemblies and metal lavatory sink pop-up assembles then transitioning to plastic tubular. I consider metal sink drain assemblies to be a superior choice over plastic.  A rule of thumb I usually follow is if the drain is hidden in a cabinet or vanity I use plastic tubular and if a drain is exposed like on a wall hung sink or, pedestal lavatory sink I use chrome plated brass tubular or whatever other finish is desired. This is only for cost and appearance in these cases. The plastic pipe is inexpensive and is very durable when properly installed. While the plated brass costs much more than plastic but has the looks you want to see on an exposed drain. The problems come when people mix parts such as metal nuts on plastic threads and plastic nuts on metal threads, this often results in damaged threads and a loose connection that leaks. Another common mistake I have seen is mixing components of a part. P-traps come in two parts, the bend and the wall outlet. Where the two pieces of the p-trap connect different methods of sealing are used for brass and plastic. Plastic p-traps use a bevel connection and the chrome ones use a rubber washer held in place with a flange compressing against a flat surface. If you combine these 2 different ways of sealing it will leak.

Slip Joint Nuts L to R Chrome Plated Brass, Plastic, Zinc

Slip Joint Nuts L to R Chrome Plated Brass, Plastic, Zinc

Zinc slip joint nuts are another commonly sold item that should be avoided. In theory they should be fine to use but the reality is even the smallest amount of leakage will turn into a big leak when the zinc slip joint nut corrodes and falls apart. It will not be the simple matter of tightening the connection like a brass nut often would be. The brass tube may have to be replaced as well if the zinc slip joint nut will not come off the brass. Stick with using brass or chrome plated brass slip joint nuts on tubular brass they are vastly superior to the zinc slip joint nuts.

Slip Joint Washers L to R Poly, 1 1/4" X 1 1/2" Poly, Rubber

Slip Joint Washers L to R Poly, 1 1/4" X 1 1/2" Poly, Rubber

The slip joint connections should not be installed with Teflon tape or, thread sealant. The actual sealing is done by the slip joint washer. The washer is compressed into a bevel by the slip joint nut. This seals it against the tube and the slip joint hub and it also grips the tube holding it in position. If any thread sealant was to get in this area it could serve as a lubricant allowing the joint to slip apart. Some thread sealants may also have an adverse effect on the plastic. My personal preference is to use the plastic poly slip joint washers on plastic tubular and to use rubber slip joint washers on the tubular brass. I feel that rubber grips the chrome plated tubular brass much better than the poly slip joint washers holding the connection in place better so things don’t fall apart. Slip joint nuts if they are plastic should be hand tight with just a little extra with a pair of channel locks, metal slip joint nuts should be tightened enough that the connection locks in place and doesn’t slide.

This next part is the Holy Grail of putting a tubular drain together. Granted the tips I gave above are important, but, if you are not going to do this part right you might as well do everything wrong. Without getting this part right you will have leaks and or, a drain that falls apart. It is absolutely critical that the tubes are cut long enough so that they almost bottom out in the hub and all the tubes should come together in a relaxed state. What I mean by a relaxed state is that there is no bending needed to make the parts stay together. The connections should almost want to stay together even if the slip joint nut was not tight. Only by having all the tubes cut to the proper lengths and having everything plumb can this be accomplished.

The best way to get the connections right is to use the fact that the p-trap is the part that can move virtually anywhere.  By varying the wall outlet length and swiveling the p-trap you have quite a range of motion. Start at the wall and make sure the trap can be aimed at where the drain from the sink is going to land. You can use a bend coming out of the wall to aim the drain in the right direction if needed. I usually put the trap in its approximate place coming out of the wall first leaving the trap loose enough to swivel. The connections at the wall and the sink are rigid and the variable is moving the trap so I want to work from both the wall and the sink towards the trap. After getting the trap roughly in place I start at the sink and work down to the trap. Using the trap set in place as a guide to get lengths of the tube cut correctly. I want them to have the maximum insertion into every hub without bottoming out. If the tube bottoms out it is too long and may stress another connection. If a tube is short and barely into the hub the support the tube gets from the hub will be lacking, there will be flexing at that joint and it may come apart or leak. If there are any horizontal tubes like in the case of a double bowl kitchen sink I like to have them up as high as possible, this maximizes under sink storage and lessens the probability of damage occurring. When I get all the tubes in place coming down to the p-trap, I cut the tube to the proper length for the slip joint connection to the trap. I then take apart the trap swivel connection and put the trap in place loosely. I then work on the trap height and the wall outlet length so the beveled swivel connection stays together without any stress. I then put on the swivel connection nut and tighten all the connections. When you put the drain together in this manner the drain wants to stay together and even with vibration from a disposer and an occasional knock, the drain remains together and leak free.

Comments

  1. Mike says

    How can I stop the wall pipe from leaking and…
    Do I now look for a clog in the vent pipe.
    I’ll explain…
    I had a completely clogged bathroom sink drain and rusted 1-1/4″ p-trap.
    I removed the wall pipe and snaked the drain (behind the wall) removing large amounts of sludge and hair.
    I replaced the P-trap (w/a brass one), washers, fittings and wall pipe.
    (I tried the PVC pipes, but the wall pipe was too loose [brass pipes behind the wall] and leaked at the wall.)
    The new brass wall pipe fits snugly, though still leaks slightly at the wall and…
    the drain is now very slow.
    Six months ago our tub was clogged. I removed the clog from the access in the basement.
    The sink was not clogged when the tub was. We only have the one access in the basement.
    Thanks in advance for your help.
    – Mike

    • says

      Hi Mike,

      If the sink is not draining you have a drain problem and you didn’t snake far enough to clear the blockage.
      Vents normally do not cause problems with drainage except under very limited circumstances that probably do not apply in your situation. U slip joint washer at the wall connection should make a leak free connection.

      Redwood

  2. Nonny says

    My problem is that the trap bend portion doesn’t reach the T pipe or the main portion of the sink pipe under the cabinet. It must have come loose after the last earthquake. the only way it goes in is if I lift up the pipe. Do they make longer pipes for this?

    • says

      Hi Nonny,

      If I’m picturing what you have correctly you should be able to cut the tee off a little and then use an extension tube that is also cut off to give you plenty of overlap in the slip joint so it doesn’t fall apart. I like to have the tubes at rest almost bottom out in the slip joint socket. Don’t let them bottom out though because that will just make stresses else where.

      Extension Tubes

      Redwood

  3. Aaron says

    I just installed a new pedestal sink (all plastic/PVC), and I keep getting a leak at the wall. I just hand tighten the trap into the wall, then I tried giving a 1/4 turn and still a leak. It’s driving me crazy i have no idea whats wrong.

    • says

      Hi Aaron,

      Is it going straight into the slip joint at the wall or is it angled and under stress?
      Did you put a slip joint washer in at that connection?
      Is the washer in good condition or, has it split?

      Redwood

      • Aaron says

        Redwood:

        Slip joint is the washer/nut that screws onto the wall connector right? I was actually thinking it may be under some stress as well (it’s a very, very, very slight angle downward). The washer is brand new, but I guess it could still be damaged, but it looks good to me.

        ps. just googled slip joint washer… the plastic white/clear washer that comes inside the plastic nut (it came with the nut in the trap kit)? yes that’s on there. And I also learned that the tapered end of the washer should be facing the nut (it wasn’t), so I’ll try that as well.

        • says

          Hi Aaron,

          The pipe into the wall should actually pitch slightly downward toward the wall allowing it to drain. I usually set that in place then raise the trap up to meet is in a stress free joint.

          What kind of pipe is extending out of the wall? Is it in good condition or badly corroded if metal?

          The tapered end should into the pipe with the flat end facing the nut. See the cross section drawing above.
          You may want to try using a rubber washer also pictured above. If the pipe coming out of the wall is plastic it may be cracked in which case the leak will usually get worse the more you tighten it.

          Redwood

          • Aaron says

            Redwood:

            The pipe coming from the wall seems like any other older metal pipe… it’s a bit brown (but doesn’t seem rusty). I’ll try to redo it today, and cut the pvc pipe (from the sink to the trap) down a little bit to relieve some stress on the wall pipe, and to create the slight downward angle from the trap. And I’ll also just buy a new washer.

            • says

              Hi Aaron,

              Are you using a brass or chrome plated brass slip joint washer at this connection. You should be.
              Also the ends of the threaded pipe coming out of the wall needs to be smooth to be leak free.

              Redwood

          • Aaron says

            Redwood:

            Ok, I just replaced the washer and nut with a new rubber washer and plastic nut, I created a slight downward angle from the trap to the wall and I hand tightened the nut… still drips. Is there supposed to be Teflon on the wall pipe? The wall metal pipe is not corroded, and the pipe that is going into that from the trap is of course PVC, so I’m still clueless. It seems to be dripping from the bottom (but of course because gravity forces the water that way). Anything else it could be????

  4. says

    The left side of our double kitchen sink has a slow leak when water is held in the basin–as in to wash or soak dishes. The leak is coming from the point where the pipe work connects to the underside of the sink. When I wipe the threads dry, a black gummy goo wipes off. Is this degraded glue or sink sludge? To repair this do I need some type of glue or sealant? All other joints in the pipework are tight.
    Thank you for your assistance.

    Diana

    • says

      Hi Diana,
      The black goop is sink sludge from the leaking. Sometimes it is hard to tell exactly where the leak is coming from without a close look and wiping it with a paper towel. There are two places where it can come from and you have mentioned one of them where the tailpiece connects to the basket strainer assembly. Typically replacement of the washer and sometimes the tailpiece fixes this leak. Typically there is a different kind of washer used at this connection that is “L” shaped with a flat part that fits against the basket strainer and the other part extends down into the tailpiece.

      The other possible leak is that the basket strainer is leaking where it connects to the sink and the water is dripping down. If this is the case the basket strainer should be replaced. I would avoid the type that has a large diameter washer that tightens up against the sink as they are very difficult to tighten and frequently leak.

      Redwood

  5. tom says

    sir: we are redoing our bathroom and just put in a cabinet/sink. i notice that the pipe from the floor with the P trap does not line up exactly with the metal pipe coming out from under the sink. the plumber used a pvc pipe, with a flexible middle section, to make the connection. now if the P trap could be turned a little then that pipe would line up almost exactly with the sink drain. the problem is that this cabinet has a short wood barrier situated between the 2 pipes.
    i was thinking of 2 solutions if we should avoid flexible pipe: cut out a section of the board so that the P pipe can be swiveled or forget the flexible pipe and use ridged pvc but this would mean adding two 90 degree turns that i think might be bad.

    the plumber is coming back out tomorrow. your comments are appreciated.

    Tom's Sink Drain

    • says

      Hi Tom,

      Thank you for e-mailing the picture showing your drain.
      I congratulate you on not wanting the flex there. It would certainly at least develop into a smelly drain.

      Notching the divider to create room for the p-trap to swing is certainly an option.
      Properly done it would not make the strength of the vanity suffer.
      The one drawback would be if you ever go to remove the trap to clean the drain or, remove an object from the trap that was dropped down the drain, it will be difficult to catch the water in the drain or, sink without spilling it.

      Another solution is to use a double offset drain tube or, a couple of 45 elbows and a length of straight tube to route the drain away from the divider. Those fittings are pictured below.

      double offset drain and 45 elbow

  6. Josh says

    hi, I just installed a new sink in my bathroom and when i turned the water back on I noticed a small leak. The leak appeared to be coming from the upward portion of the trap where it connects to the horizontal part running into the wall. I gave the slip nut a 1/4 turn and the leak almost completely stopped. I completely dried the area and then ran the water again. I do notice that the same area gets ever so slightly wet and a few minutes later I get 1 drip from the trap. Do I just need to turn a bit more(pipes are pvc)? The other thing I had noticed is that the threads on this part of the trap that I am talking about has a brownish residue which looks like some kind of sealant. The main question is should I be using some kind of tape or sealant on this thread. Thanks for your help.

    Josh

    • says

      Hi Josh,
      This leaking connection should not have any sort of sealant or, putty on it.
      In fact these substances can often cause leaking by making the beveled sealing surface have gaps which allow leaking.

      The problem may have been caused by the contamination of the surface or, it may have a crack in it causing the leak.
      In either case I’d recommend starting out fresh with a new one. After all you have a nice new sink what’s a couple of dollars more for a nice new trap.

      Redwood

  7. Justin says

    I just replaced both sinks and faucets in my master bath. Installation was quite easy as the sinks were the same depth as the old ones. The only difference is that the drain tubes from the sinks are plastic vs metal in the old ones. After installation, I am experiencing leaking from the p trap connection to the vertical tube from the sink (both sinks). I have tightened the slip joint nut as tight as I can by hand with a little extra with a pair of channel locks. Is it possible that my new vertical drain tubes coming from the sink have a smaller circumference that the old ones and that I need a smaller circumference p trap tube? Or do I just need a smaller circumference slip joint washer or plastic vs existing rubber?

    Thanks,
    Justin

    • says

      Hi Justin,
      The lav sink drains are only 1 1/4″ diameter vs. 1 1/2″ diameter used for other drains. The P-Trap should have come with a thicker washer that was 1 1/2″ on the outside diameter and 1 1/4″ on the inside diameter. This should fix your problem and provide the tight seal that you need.
      Redwood

      • Justin says

        Thanks for the quick reply. The p trap did come with the thicker washer with varying diameters as you have described, and that is what is being used. However leaking exists. It just doesn’t make sense. Could the washer be upside down?

        • says

          The flat side of the washer should go towards the nut as shown in the picture in the article above.
          The taller side of the U-bend should also go on the sink drain.

          • Justin says

            After some investigation and testing, I discovered that the leak was not from the p trap connection. The leak is coming from the top nut of the drain assembly. The water was dripping down and gathering in the p trap connection leading me to believe the leak was there, but after turning the water on and watching for the leak I learned the true source of the leak. So here is what is happening – water is entering into the sink’s overflow cavity via the two overflow holes in the drain assembly pipe when the water is running (unavoidable I am guessing given that the overflow holes must be there to relieve any overflow entering into that area from the sink basin overflow hole). The water is accumulating in the overflow cavity and seeping through the threads of the top drain assembly nut. I was happy to have found the source of the leak and thought that applying some tape on the threads and a couple extra turns would do the trick to stop the leak. Still leaking. Very frustrated at this point as you can imagine. What am I missing here? I have to say that after examining the overflow area and design, I am a bit perplexed as to how water that enters the overflow cavity ever escapes? Sure most of it should through the overflow holes in the drain assembly pipe, but not all of it right? Does the water just sit there unitl it evaporates? Please help, this seems too simple to call a plumber in.

            • says

              Good job with the investigating of the leak, and what you have found eludes many people even plumbers. You have no idea how many plumbers effectively “Glue” in a lav sink pop up assembly with Silicone RTV because they think that is the only way to install a lav sink drain without a leak down past the mack washer and nut.

              Unscrew the nut and slide the rubber washer down, than apply Teflon Paste (Pipe Dope) on the threads where the mack washer will land when tightened. That is what I do when installing a lav sink pop up assemble to avoid leaks. If you look through the comments here there is no doubt I have said it several times. Maybe its time for and article on that.

              • Justin says

                Sorry, meant to reply earlier. Thank you very much for the advice and direction. The paste worked great; no more leaks. Agree this should be something that is included in the instructions above or in a general article.

                All the best,
                Justin

  8. Z from DC says

    This helped me a lot. I had a space between my p-trap and drain elbow from the garbage disposal.
    I have since added a piece of pvc to fill the space ( without bottoming out) all is ok.
    Thanks
    Z from DC

  9. Jeff says

    I have a brass 1.5″ female adapter coming out of my wall for my bathroom sink drain (drain in wall is copper). I need to hook up a p-trap and have no idea what I need to make this happen. I bought a 1.5″ brass male adapter that I can screw into the main drain. The other end of the adapter has 1.25″ threaded male adapter on it. After reading a ton of different web sites and other things I am greatly concerned, should I not screw my PVC 1.25″ p-trap assembly onto this because I will be going from PVC screwed onto brass? If it is ok, should I be using teflon tape on the brass? Is there some sort of brass fitting I can screw onto the 1.25″ male end to make it a female end so I can screw the pvc p-trap assembly into it? I have no idea what to do to be honest.

    • says

      Hi Jeff,
      You can secure the p-trap to the adapter you purchased by just using a 1 1/4″ brass or chrome plated brass slip joint nut and a rubber washer. No thread sealant or Teflon tape is needed.
      Redwood

      • Jeff says

        Thanks, I used the compression fittings that came with the parts but wasn’t confident when I cranked them down. The tube wall pipe kept moving in and out. I went with a slip joint and washer and that seemed to take care of the issue.

        • Jeff says

          Thanks for answering my previous question. Now I am having trouble with the water leaking where the rubber gasket meets the bottom of the sink. I think the water is pooling in the over flow cavity and it just sits there. So…Should I just throw a crap load of teflon tape on there and some pipe dope? I obviously don’t want to seal up the over flow cavity because that kind of defeats the purpose of the overflow. Should I fill the top drain tube holes with putty or silicone making it impossible for water to enter that cavity?

          • says

            Hi Jeff,
            Your leak is actually quite typical for lav sink drains, and most people even trained plumbers don’t realize the cause of the leak. The debate of whether to install lav sinks with plumbers putty or, Silicone RTV has raged on for years and will never end.

            By design any lav sink with an overflow will have this area that holds water. The flange on the bowl side of the sink only provides sealing to keep water from going down the drain, water leaking under the flange in the sink bowl will never go anywhere except down the drain causing the sink to gradually empty while the stopper is in place.

            The under side of the sink is sealed to the drain by the rubber mack washer and in a vast majority of the time it seals very well against the sink itself. However, the threads on the drain used for tightening the mack washer in place with a nut usually are the cause of leakage with water running down through the threads under the mack washer because the rubber does not press into the threads well enough to seal them. The solution is to coat the threads on the drain under where the mack washer will land when tightened with Teflon Paste such as Rectorseal T+2 or some other brand, then tighten the nut securing the drain in place. Doing so will result in a leak free connection every time.

            There is no need for any other sealing such as Teflon Tape or, Silicone RTV on these connections to have a leak free installation. Using these things will only cause a leak or, increase the difficulty of replacing the drain assembly in the future.

            Redwood

  10. Debbie says

    Help… I have an older rental apartment that I replaced the p-trap on the bathroom sink. Come to find out, the issue was the rusted pipe coming from the wall/vent drain. I attempted to cut out the rusted portion, but the whole pipe came out of the wall. This appears to be a slip joint (?)…there were no threads on the end of the pipe… not sure if there aren’t any threads or they are rusted away. Anyway, I slipped a pvc pipe back into the joint. Now, I have a leak coming from around the pipe and out of the wall… no wonder there was some kind of epoxy or cement plastered around where the pipe exits the wall. How do I stop this leak?

    • says

      Hi Debbie,

      First of all are you the tenant or, the landlord?

      If you are the tenant then stop right now and call the landlord! The plumbing belongs to the landlord and the landlord’s blessing is required before you tough anything or you will incur significant liabilities by touching the landlord’s plumbing.

      Now if you are the landlord. If the pipe that broke off goes straight into a tee in a vertical pipe you may be able to take the threaded portion if the broken pipe that is remaining broken off in the tee out of the tee and put on a new threaded nipple to make the repair. If the pipe that broke off goes into an elbow which then travels horizontally across the wall most likely the wall will have to be opened up to replace the horizontal section of the pipes as they will certainly be in the same poor condition as the pipe that broke off. The pipe will probably go horizontal several feet over behind the toilet where it will tee into a vertical line. This is typical in many bathrooms where the toilet is next to the bathroom sink. Vertical lines are almost always in better condition than horizontal pipes.

      The broken off nipple may be removed from the tee by carefully cutting almost through the broken off nipple with a hacksaw while being careful not to saw into the threads making 2 cuts close to each other. Once the old nipple is cut most of the way through with the 2 cuts the cut out piece can be pried or chiseled out the the rest of the broken nipple collapsed on itself to remove it from the tee. The threads may need some cleaning with a wire brush but will be usable in many cases. The threaded portion of the pipe is the thinnest so it almost always is the first place to break. If the threads aren’t any good then the wall will have to be opened up.

      This is one of those situations where the experience of a plumber in removing the old broken off nipple may have significant savings in keeping a small job from turning into a bigger job.

      Redwood

  11. Darin says

    I have a bathroom sink with a metal drain pipe that comes out of wall and to p-trap well the nut is broke that is attached to pipe coming from wall and pipe into wall is soldered in the tee in the wall is there a way to cut pipe and fix without getting into wall?

    Darin's Lav Sink Drain

    • says

      Hi Darin,
      With the nut as badly corroded as it is and the obvious signs of corrosion on the chrome plated brass tubing I’d expect that the tubing will be in very bad shape somewhat similar to chrome plated tin foil and fall apart the moment you go to touch it. You can probably even push your thumb through the tube on the bottom of the bend.

      I would expect that under the escutcheon where the tube goes into the wall that there is a slip joint nut there where the tubing can be removed. Most of the time there is although sometimes it may be soldered, if there is a slip joint nut you should be able to easily replace the tubing.

      With the corrosion visible in the picture I’d certainly replace the p-trap which appears to be a 1 1/4″ p-trap and I’d expect to find the tailpiece coming down from the sink drain to be in very poor condition as well. Another picture showing the entire drain from the bottom of the sink to the wall would allow me to say with greater certainty what you will need to do for this job.

      Please check under the escutcheon to see how it is connected and post back with a picture showing more of the drain, and I’ll be able to offer more advice.

      Redwood

  12. Rob says

    I have just installed a new vanity in my basement bathroom. I had no problems with the vanity, sink and faucet installation, and thought that the installation of my new Moen pop up drain assembly went smoothly, until I noticed a very slow leak coming from underneath the sink near the locknut.

    Initially, I thought that I just didn’t have the locknut on tight enough, but that wasn’t the problem. After taking the drain assembly apart and more closely examing the parts, I noticed that the beveled gasket is a little too big. In other words, when pushed up against the drain hole of the underside of the sink, it does not sit flush, so it is easy to see why there would be a slow leak.

    With the Moen pop up drain assembly (Moen’s instructions were terrible and none of the parts were labeled or explained), there is the rubber beveled gasket, then there is another flat rubber gasket, followed by a plastic gasket (I believe this is also known as the friction ring and prevents the locknut from moving the rubber gaskets upon tightening), and then of course the locknut.

    Why are there two rubber gaskets (flat and beveled)? Do I HAVE to use the beveled gasket, or can I do away with that and use the flat rubber gasket provided?

    Thank you.
    Rob.

    • says

      Hi Rob,

      The thick beveled washer fits up into the hole of the sink sealing and centering the drain. Your leaking problem can be solved by coating the threads that go against the rubber washer with Teflon paste. The rubber washer is not pressing into the threads enough to seal them and the water is leaking down through the threads. Teflon paste will stop this leak but the instructions will never tell you that.

      Redwood

      • Rob says

        Sorry, I added a new post and didn’t “reply” to your post.

        With the Teflon Paste, how long do you have to wait before it sets and you can turn the water back on?

        Thanks,
        Rob.

          • Rob says

            Hi Redwood,

            I took apart the pop up drain assembly, cleaned it off good to make sure that the threads were clear of any small pieces of rubber from the gasket etc., and added the Teflon paste around the threads where the gasket and locknut would sit. Put it all back together and noticed a difference right away in just the sound of the water running down the drain, and most importantly it was bone dry – no water running down the threads any more, so it was definitely due to the gasket not being tight enough around the threads. I will check from time to time over the next couple of days to be sure, but it looks like the Teflon paste did the trick. If only I had known about this sooner, it would have saved me a lot of hassle, time and frustration!

            Thanks very much for the advice, Redwood. It is much appreciated!

            Rob.

            • says

              Hi Rob,
              It works every time! I wouldn’t worry too much about checking it for leaks, I’ve never had a customer call back since I started using this technique and it’s been a few years I’ve been doing it. All my fingers and toes aren’t enough to count on.
              Redwood

              • Rob says

                That’s music to my ears! I did check it a couple of times last night and it’s still dry, so I think I am now ready to start placing some items in the vanity cupboard now without the fear of them getting wet.

                Thanks again for your help!
                Rob.

  13. Rob says

    After further investigation online, it looks like the beveled gasket is fine and that it doesn’t fit in the hole underneath the sink, as snug as I first thought (I can see this from Moen’s diagram – http://www.moen.com/consumer-support/installation-help/tutorial?id=moen0114).

    My guess is that I need to pick up some teflon type paste sealant (pipe dope) and put that around the threads where the beveled gasket and locknut sit, as it seems like the water is leaking down through the pipe threads.

    I’m still confused why I would have the flat rubber washer, as none of the instructions I’ve found even mention it. Based on what I have read, the beveled gasket and the flat, plastic white washer, along with the locknut is all that’s required.

    Does it sound like I’m on the right track here? This is a very frustrating process. Thanks!

    Rob.

  14. Rob says

    Thanks, Redwood. I only just saw your post after I made my second post. As you can see, that’s exactly what I was thinking, but at this point your expert opinion is much appreciated.

    I’ll go and buy some teflon paste and will give that a go. I’ll let you know how I get on. Thanks again!

    Rob.

  15. Jeff W says

    I’ve had fits since installing a new kitchen sink, I can’t get the drains to seal at the tub(s). I finally figured out that the threads don’t go far enough for the large diameter rubber o ring to tighten. Yes, I did use putty in the same roll up string way as usual, but it pushes out what it needs too, then after wiping excess on top it starts leaking. I’ve looked everywhere I can think to find a metal o ring to make the rubber o ring push a bit further up to bypass the thread loss difference. I have bought new metal drains and replaced, but in reality it is the thickness of the tub, not the threading that causes the problem, its so thin its sharp, trust me my fingers still have damage. It is a lifetime warranty sink from Lowes. I did contact the seller on the box, and Lowes. The Lowes guy had no idea what I meant and the seller stated that we only sell them we don’t manufacture. So I ask who manufactures, no answer there that he could give so I can imagine foreign which is not a problem. If I could find a metal spacer for both side drains of a thickness that would not crush the rubber o ring but at least snug it I think I could solve. I’ve entertained the idea of some type of serious sealant on everything but in reality I need to cross out every other avenue first. The center pipe isn’t giving a problem at all, just isn’t enough thread push on the nut to take over for the sink thickness if that makes sense. Any idea’s? Thanks

    • says

      Hi Jeff,
      The kitchen sink basket strainers with the large diameter nut that tightens on to the rubber washer are very difficult to get tight enough not to leak. The large surface area of the nut creates a lot of resistance to turning and gets even worse when plumbers putty gets squeezed down into the threads. A large number of plumbers believe the solution is to glue the basket strainer in place with Silicone RTV.

      I believe a much better solution is to use a better designed basket strainer such as the Kohler Duo-Strainer which is a bit pricey or, what I use more often is a Double Cup Basket Strainer shown in the picture below. The double cup design uses a cup like washer or spacer and a 1 1/2″ diameter nut to tighten it in place. This design is much better in my opinion and I’ve had very good results with them.

      Redwood

      Kitchen Sink Double Cup Basket Strainer

      • Jeff W says

        Great, Thank You so much Redwood. Going to order the Kohler above right now, your a lifesaver. I had thought about the silicone, but in reality i didn’t think even with cure time that the whole bead would cure inside enough to have a good time expectancy before leaking again. Then the squeeze out probability of the gasket with silicone pushing down onto it was a concern. If any of this makes not much sense its because im not a plumber lol but trying to think ahead of the curve.

        Ok, re read that & realized i confused the kohler for the cup type. That is what i will get, the cup type as you suggest. I spent 3 days under the sink taking everything out including the flooring from water damage, replaced all new plywood then covered it with a thick flat plastic siding material that i glued down. The only problem i had is there is a new pan now to catch the drip from that one spot, all the new piping was great because i took time and care with every piece so you can imagine i was dismayed having to put a catch pan back down. Thanks again Sir for your help

        • says

          Hi Jeff,
          Good thing you caught the difference between the Kohler Duo-Strainer and the regular double cup basket strainer.
          The Kohler Duo-Strainer is a bit high end on the wallet, and depending on the model and where you are shopping will be 3 – 9 times more than the double cup basket strainer assembly I showed.
          Redwood

  16. JonathanG says

    We purchased a home this year, which was built in the late 60′s. There are a couple of DIY plumbing projects on the list, and all the home’s drains are cast iron. Adding a fixture, for example, is difficult because tying into the existing drain requires tapping into the cast iron. So far, we’ve managed to “get creative”, but these are short term fixes. I’m looking for the best way to tie into old existing cast iron, without making things worse. Can you offer some advice?

    • says

      Hi Jonathan,
      I’m afraid that I can’t really give you a good answer that covers everything, and this would be best covered on a case by case basis. Many of these situations can easily escalate from a small job into a much larger job depending on the condition of the cast iron pipe. I could probably help you much better in the “411Plumb Forum” if you were to join and start a thread on each project you intend to do.

      Generally if you are able to attach plumbing to the nipple extending out of the wall with a Slip Joint Adapter or, a Fernco Trap Adapter and go to tubular polypropylene or, tubular abs the work is pretty straight forward as long as proper pitch, and the developed arm length, required under code is maintained.

      If you have to go inside the wall it can be much more complex as in addition to the code requirements regarding pitch and developed arm length, a number of other conditions will be met up with. Even a simple addition of extending the arm in the wall may get you beyond the code limits of developed length of the arm and require reventing. Cutting in a new Sani-Tee into the vertical stack will require that you support the weight of the cast iron stack in its original position with pipe hangers so the stack does not fall when you cut out the section or, have weight pushing down crushing the Sani-Tee you place into the stack. Even cutting the pipe could be a problem, I often use a Lenox Gold Titanium Nitride Coated Sawzall Blade with teeth designed for cutting wood when I cut cast iron, but in cases where the cast iron is not in the best of condition I use a carbide grit or, diamond blade in the sawzall. Diamond blades in a disc grinder work very well too. You could tie in a No-Hub Cast Iron Sani-Tee with No Hub Couplings or, a PVC or ABS Sani-Tee using a “Banded Coupling” such as a “Fernco Proflex Coupling.” In any case the coupling used should have a metal band surrounding it to ensure that the pipe stays aligned properly.

      I’m afraid that is about the best I can do for advice without a lot of specifics and a back and forth dialog which would be best served in the forum.

      Hope this helps,
      Redwood

  17. Steve says

    I went to replace the drain pipe in a bathroom sink. I discovered that the hole in the ceramic at the bottom of the sink has a flaw and is not round. The edge is broken off for about 1/6th of the way around the hole, and at that point the hole is about 1/8th inch wider than it should be. The original installation had used something like hot glue to fill it in; it was a golden color.

    The new pieces I have will not seal the hole. Neither will the old gasket – presumably because I broke the seal the glue was making. Neither will hot glue (which I don’t think would last long anyway).

    The local big-box building supply store sold me a rubber gasket which did nothing.

    Short of calling a plumber, what else can I try?

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