[Krupke]

Dropped a bunch of small pebbles down the bathroom sink, they got caught in the drain trap. So I tried to remove the pipe connected to the drain (after removing the P-trap), with the intention of removing the drain flange. But all the pipe did was spin, along with the drain flange! None of the videos I researched were any help because the nut is NOT separate from the pipe (see photo). It appears to be a part of the pipe.

I also tried holding the drain on top with pliers, and going counter clockwise with a pipe wrench on the drain pipe. But nothing budged. I'm at a loss to understand how to remove the pipe & drain assembly! So I decided to close everything up. I turned the pipe clockwise to try to tighten it back on (but it doesn't really stop, it will keep turning if you put effort into it) and then I put the P-trap back (no problem tightening that). NOW there is a leak, probably coming from the area where the drain meets the sink (sometimes water will continue to drain even with the plug installed, but not always).

My Bathroom Sink Drain Pipe Assembly:

[havasu]

If the drain itself began to spin, you probable disturbed the old plumber's putty inside the sink, and it will leak until you replace all the old, rusted pipe, up to and including the P trap. You can get all the replacement parts you need at all the big box hardware stores, and don't forget to pick up a small container of plumber's putty while you are at it. Lastly, if the drain and downspout are rusted together, you might just need to saw it off using a hack saw or similar cutter.

[jwwing]

Deleted - Sorry havasu - you have the right answer for him.

[Krupke]

Thanks for the reply. What you said makes sense, that I broke the putty seal while turning the downspout. But I'm still not clear on how I disengage the downspout from the drain. Even if I manage to hack the downspout pipe (though I'm not sure where), it will still be connected to the drain flange.

And... is it really necessary to replace all the pipework, if the leak is from around the drain? Or is that because there are signs of rust on the pipes?

Originally Posted by havasu

If the drain itself began to spin, you probable disturbed the old plumber's putty inside the sink, and it will leak until you replace all the old, rusted pipe, up to and including the P trap. You can get all the replacement parts you need at all the big box hardware stores, and don't forget to pick up a small container of plumber's putty while you are at it. Lastly, if the drain and downspout are rusted together, you might just need to saw it off using a hack saw or similar cutter.

[havasu]

You will probably need to shove a big screwdriver into the drain to hold it steady, while using a pipe wrench on the downspout and unscrewing. This will cause irreparable damage to the affected pipes, so this will be a replacement item for sure. As far as the P trap, yes, you MAY be able to clean up the rust, and MAY get it to seat, and MAY not begin to leak, but for a few bucks, wouldn't you want to walk away from this job knowing the parts are all new, leak free and good for a few more years?

[phishfood]

In your original picture, just above the top arrow that you drew in, you can see a red fiber or plastic washer, and then above that a black rubber washer. Using a fine toothed hacksaw, cut through that rubber washer and all the way through the drain body. The top section of the drain that is in the sink will push out through the top.

Then get a new lavatory drain, an 1 1/4" trap, and replace the entire thing.

You MIGHT get lucky and get everything apart and put back together and make everything leak free. But the hassle and aggravation that you will go through getting that done probably isn't worth the little bit of money you would spend on the new parts.

[havasu]

I would also go the extra mile and replace those gray supply lines with something newer and stronger.

[captaincool]

Why not just loosen the nut at the back of the trap weir and spin the entire drain off?