leaking p-trap after replacing

diggitydog

Hi,

I'm a DIY kind of guy that does light projects around the house. This weekend I replaced a p-trap in a bathroom that had a cracked nut. It is a heavier 2 piece black PVC 1 1/2" trap which is a little different than the white plastic ones I'm used to. I simply purchased a new 2 piece p-trap and mated the old male treaded portion of the trap (which is cemented in place to the outgoing pipe) to the new female portion of the trap which includes the new nut.

When I tightened the nut and turned on the water, the trap began to leak at the joint of the old and new sections. Aren't these supposed to be universal? They seem like they should mate up without any problem.

Am I supposed to apply putty to the joint where the groove lines up with the wedge on the other piece? It seems to me that that type of wedge joint should seal with compression only, but I'm not sure. Again, I'm not too familiar with using 1 1/2" black PVC and the joint in the trap is new to me. Any other ideas as to how I can stop this leak?

Thanks,
Dave

ron schenker

I'm not a plumber butt, the "black pvc" is actually "ABS" and should work ok if you threaded it on properly(no cross threads)
I'm curious as to why you didn't replace the old P-trap with an original type pvc one.
You could try to wrap some teflon tape around the threads for a better seal
I'm sure a plumber will chime in soon

Ron The Plumber

Apply some pipe dope to the threaded part, should fix the leaking.

diggitydog

Ron Schenker and Ron the Plumber,

Thank you both for your replies.

Thanks for the clarification on the ABS. Being a complete novice I assumed all plastic was classified as PVC.

I replaced it with the ABS because that is what was previously there. I simply went to the home improvement center and matched up the 1 1/2 ABS trap with the one I brought from home.

I had already tried the teflon tape on the threads and that did not work. There was also no cross threading. I tried the connection several times with various amounts of tape and compression. Everytime, it continued to leak.

What did work is the TFE universal thread dope. I applied the dope to the male "wedge" portion of the 2 piece trap, not the threads. This time, when the male wedge slipped into to the female groove of the other piece, whatever gap was previously there, filled with dope.

So far no leaks!

Thanks again for your replies,
Dave

handypilot

For future reference, Teflon tape works well for some fittings, but not plastic. Always use pipe dope for plastic connections. Now that you've found TFE pipe dope, you won't use anything else...it's good for all applications!

philodog

I have had this problem several times with new ABS p traps. I tried tape on the threads, pipe dope, severe tightening and what finally worked was Teflon tape not on the threads but on the cone shaped part that fits in the groove. I`ve learned that is where the sealing occurs, not at the threads. What a relief when it finally stopped leaking.

KevinACrider

Wow, you bumped a 5 year old thread. But I'm glad you did, I have this EXACT problem right now! The nut is wrenched tight and it still leaks. Once I get it off I want it done for good. What is the best solution for sealing up the groove area?

Service plumber

Rectorseal tplus2

oh'mike

Always run you finger over the mating surfaces before you install---occasionally there id a burr or bit of casting flash---scrape that off with a knife and you avoided a leak.

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KevinACrider

Mike, I did make sure there were no burrs, but I think the joint just did not make a solid seal all the way around. I have a very small drop on the inside of the P and was hoping I could use plumbers putty, some caulk or some other sealant to put in between the joint to fill any voids. I only want to do this once, and with whatever material I use being permanent, I need to do it right the first time.

Service Plumber, I will look into the Rectorseal T+2 and see what I can find.

philodog

Hi Kevin
Anytime I find a solution to a problem that has driven me crazy I post it online to appropriate forums so others searching for a solution to the same problem might come across it. My way of adding to the wonder of the internet. If you haven`t already done so try the teflon tape on the joint. I wrapped it six times or so around the cone shape and didn`t put anything in the groove. It worked instantly for me on two different sinks that were leaking. Let us know if it worked.

KevinACrider

I appreciate your suggestions, I am just hesitant to go with the teflon tape solution as I fear it may not prove the test of time. I've had great success with teflon tape on threads but I think there has to be a better way.

I talked to a local plumber who suggested filling the notched half with sillicone sealant before putting it back together and letting it fully set before running waer through it. Any thoughts or opinions on this or would plumbers putty be a better route to go?

TheEplumber

I have the best luck with a teflon based pipe dope. Apply a coating to the mating surfaces- to help fill any small voids. And a small amount to the male threads- for lubrication, helps break the friction while tightening. When testing for leaks use hot water and tighten nut if it drips. If trap still drips - buy a new one.

ben's plumbing

yes yes teflon pipe dope on the two surfaces.....and a big yes test with hot water because it causes it to expand if small leak tighten up if still leaks ....replace trap......

huesmann

Compression fittings never work for me, long-term. It's better to get one of those rubber P-traps that just hose-clamp to the drain pipes.