Leak under bathroom sink.

[OswegoLion]

Water is lighly seeping out at plastic ring right under sink. I tried hand tightening but doesn't seem to stop it. We've been living in 5th wheel all summer and this is our first leak. Help.

[Bama Rambler]

Is it the drain fitting or a water line leaking?

Can you post a picture of it?

If it's the drain strainer leaking you can loosen it, lift it up a little and caulk under it to stop it from leaking. If it's the compression fitting on the P-trap or tail piece leaking you may need a new wedge ring to get it to seal.

[kenandterry]

Is it the back flow preventer for the black tank flush leaking?

[SeaDog]

These fittings are not designed to be super tight (that can cause a leak) losses the fittings and retighten hand tight and see if that stops the leak. I also agree with bama rambler

[OswegoLion]

I will send a pic when I get home

[Ford Idaho]

Originally Posted by kenandterry

Is it the back flow preventer for the black tank flush leaking?

First thing I would check due to the some what poor performance history.

[OswegoLion]

Water is running under the black tightener connecting to silver threaded short pipe.

[NMWildcat]

As in bama ramblers post, take the drain apart, clean off old putty on the inside of the sink side (if there is any) and use plumbers putty under the lip of drain inside the sink. I have seen a few with rubber gaskets but I would still use the putty (remove gasket). Get a ball of putty and roll it into 1/4 'rope' that will go all the way around the drain lip.

[Bama Rambler]

X2 Scott's suggestion.

It's possible that they left the putty/gasket off when they assembled the sink.

[OswegoLion]

Not a plumber but will try. How do I take drain apart? Step by step. Thanks

[Ford Idaho]

You should be able to unscrew it by hand, counter clock wise.

[Bama Rambler]

There should be a nut below that piece. Loosen that nut then unscrew the nut in the picture and you can lift the drain up and clean the existing sealer from under it (if there is any). replace the sealer and reverse the procedure. As said earlier, you don't want to overtighten the nuts on these connections. Good and snug should be plenty.

[nomad297]

Originally Posted by OswegoLion

Water is running under the black tightener connecting to silver threaded short pipe.

This leak is not coming from the top of the drain at its flange - it is coming from where the rubber seal above the nut you have pictured is not sealed properly to the bottom of the sink and/or where it should seal at the tailpiece threads.

This is typical with cheap plastic lavatory drains, and the way to deal with it is to loosen the nut, slide the bottom gasket down so you can see about ten threads and put pipe dope on the top of the seal and on the threads you just exposed. Now, tighten the bottom nut back up. Problem solved.

The thing about plastic drains like this is, you have to get the bottom nut tight enough to compress the rubber seal around the threads of the tailpiece. Many of these cheap drains can't be tightened that much without splitting the top flange, so you have to be careful to not overtighten the nut, but get it tight enough to make the bottom seal.

This problem is a common Monday service call for me. Homeowners spend their entire weekend installing a lavatory faucet or two which they bought at Home Depot or Lowe's with the junk plastic pop up assembly, and they just cant get it to stop leaking (right where yours is leaking). I show up and have the problem fixed in a couple of minutes only to be criticized for how much I charged them for something that took me so little time.

Edit: I realized that I overlooked one important factor - many RV lavatories don't have overflows like residential lavatories. Without an overflow, the tailpiece should not have slotted drain holes in the top portion. If this is the case, just resealing the flange at the bowl should do the trick.

Bruce

[Jeff_and_Abby]

Originally Posted by nomad297

... I show up and have the problem fixed in a couple of minutes only to be criticized for how much I charged them for something that took me so little time.

Yeah, some people's kids.

If it was as trivial as they want to make it out to be, then why did they call you in the first place.

Itemized statement:

Putty . . . . . . $0.75
Knowing WTF to do . . . . . . . . $75.00

We both work in Corporate I.T. - Systems / Tech Services ... we don't call them customers, we call them Lusers. The "L" is silent. A bigger bunch of wanna-be crybabies, you will never meet.

Hence, we LOVE camping out in the forest !!!

[OswegoLion]

Nomad what kind of pipe dope?

[Bama Rambler]

As Nomad said in his edit, your drain doesn't have to seal at the bottom nut. Just get some plumbers putty or butyl tape and run it around the top flange inside the sink and put it all back together and tighten it down a little and it should stop the leak unless the drain piece is cracked.

Once you tighten it down you can trim any excess putty off inside the sink.