Leaky P Trap

[jyl]

I know I'm no plumber but fer blanks sake why is it so hard to stop the bathroom sink P trap from leaking?

My drain exits the wall rather high, so a one-piece P trap doesn't work.

I have to use the two-piece kind: the piece that goes into the wall and makes a 90 deg bend down, plus the trap that is a U and connects to the tailpiece on the basin.

Anyway, the trap always leaks. I've bought all new pieces, used tape and putty, it always starts leaking after awhile.

Doesn't anyone make a single flexible piece that will make a continuous connection from wall to tailpiece and can be bent like Gumby into a P shape?

[porsche930dude]

Did you try a brass trap? The cheap plastic ones tend to be more apt to leaks because they have imperfections and easy to distort. Also is it a pedestal sink? maybe its moving around

[rwest]

There are flex pipes, but usually not code and you know they will clog like a mother with the grooves catching stuff.

Plumbing sucks. I would bet your problem stems from something being crooked. Maybe you can glue part of the trap in place to get things square and then install the rest.

If you start using putty and tape where it isn’t meant to go, it won’t help.

[Por_sha911]

Have you checked to see if the leak is coming from above the trap and running down the pipe?

[look 171]

The connection on top of the P trap is below the water line? Got a pic, John?

[wdfifteen]

At which joint is it leaking?
Leaks are usually due to misalignment or improper assembly.

[LakeCleElum]

I have neglected to install parts "B" and "C" before.

[URY914]

Whenever I work on a trap I leave a bowl under it to catch any drips. After a time the scale will build up and stop the leak. But your water is different.

[Por_sha911]

Along with what Bob said, parts B & C are cheap and can be replaced instead of reused.

[john70t]

All the parts should line up and slide together easy.

It's the wrong way but a buddy said to use silicone adhesive on the threads. I never have.
Goes on liquid and dries one piece.
The next plumber ten years from now will swear at ya.

[Crowbob]

Originally Posted by john70t

All the parts should line up and slide together easy.

It's the wrong way but a buddy said to use silicone adhesive on the threads. I never have.
Goes on liquid and dries one piece.
The next plumber ten years from now will swear at ya.

Not when it starts leaking again in a couple weeks.

[jyl]

It is a pedestal sink and it does move around a bit. So is that the problem? I can try to anchor it more securely.

I found and have ordered a one piece flex P hose. Sounds like it is not the right way to deal with this, but...

[look 171]

John, I am not exactly sure where this leak is? Is it at the tail piece where it enters the U part of the trap? If this part is too low, it will be in standing water and sometimes it will seep water. I suggest you use ABS and glue everything in place and thread that last part into the nipple coming out of the wall. Just remember to keep the tail piece as close as you can to the bottom of the sink.

[wdfifteen]

Originally Posted by jyl

It is a pedestal sink and it does move around a bit. So is that the problem? .

You betcha. When it moves it loosens the joins.

[widgeon13]

I had this problem some time ago, turns out it was the sink drain that had rusted out. I replaced all the piping from sink to drain.

[Zeke]

Use tile grout around the base of the pedestal. You can insert plastic wedges under the low spots as well. The sink should not move.

Also, if it's leaking at joint A/B in the diagram above, how much of the tail piece is inside the trap? It needs to go down to near the 'step' below the inlet.

[John Rogers]

In the 38 years we have had our house I have replaced a lot of sink, tub and other drains. I was told by my friend who was a plumber years before that when a leak starts to replace everything from the sink to the tee fitting in the wall. As noted make sure the straight sections are all the correct lengths so the washer and nut will be able to tighten evenly to get a good seal. I usually start at the sink and loosely assemble new drain line and then loosely install the line into the tee in the wall. Next I sit the trap section next to both pipes and make sure the ends of those first two are about 1/4 inch from the end of their seating area. If they are too short, GET LONGER ONES, DO NOT TRY TO BEND THINGS. If they are too long mark the trap locations on each one, remove them and cut with a pipe cutter if metal or shears if plastic. Remember the pipe section going into the wall will shorten in relation to the outside. I usually go ahead and use paste pipe sealer and install it tight as you can cut the length later and it will be more accurate. I usually put the nut on the wall pipe with the seal ring, making sure there are no cracks or cuts in it then tighten the nut hand tight. I then drop the new drain from the sink through, making sure it is not too long or some how I miss-measured! Put the nut and seal washer on it the tighten and seal the drain inside the sink. Then tighten the nut hand tight and make sure all connections look just like that drawing earlier. If they do tighten the nut with plumbers pliers snugly, not 500 foot pounds or anything! Good luck

[jyl]

Originally Posted by LakeCleElum

I have neglected to install parts "B" and "C" before.

Closing the loop.

The problem is that the drain is placed unusually high up on the wall, so that the piece that comes out from the wall is several inches higher than the outlet of the P trap. The sink is thus set up with a straight piece connected to nut "D" and slip fitting into the outlet with another nut/compression fitting there. Since the outlet isn't designed for a slip fitting, this sucks.

I secured the sink to the wall so it doesn't move, put everything back together, and slathered the outside of all the joints with silicone adhesive. It is a hack job, but seems to be water tight. If this fails, I will take look171's suggestion and rebuild it with plastic pipe that I will glue together. Sigh.

[John Rogers]

I have a sink similar to yours and I end up with a very short pipe section (tail piece) so all the joints line up as they should. If there are uneven connections I would have coated the male pipe with GOOP and slid it into the trap and the put a coating where the seal washer sits and then tighten the nut. A coat of GOOP after a day or so which lets the inner sealer cure will insure all holds water. I hope you did not use it for a day or two so the sealers will cure?

[wdfifteen]

Originally Posted by jyl

Closing the loop.

The problem is that the drain is placed unusually high up on the wall, so that the piece that comes out from the wall is several inches higher than the outlet of the P trap. The sink is thus set up with a straight piece connected to nut "D" and slip fitting into the outlet with another nut/compression fitting there. Since the outlet isn't designed for a slip fitting, this sucks.

And you can’t shorten the tailpiece enough to fit the horizontal piece directly to the P trap?