Can't re-attach bathroom sink drain pipe

Question

I was trying to fix a slow draining bathroom sink today, so I followed the instructions in this YouTube video. Everything went fine (and it's draining perfectly now), but I can't seem to re-attach the drain pipe (which I believe is called a p-pipe). The part that goes into the wall just doesn't seem to line up properly no matter what I do (and I must have tried 15 times by now). So it just ends up leaking out of that spot immediately.

I have included some pictures to try and show the problem - as I start to turn the slip-joint on that end it just seems to get out of alignment somehow, as if it's refusing to following the correct thread. It also feels like the pipes just aren't really in the correct spot for things to line up, but I guess that's just me not knowing what's going on.

Is there any trick I can use to getting this to line up properly and connect properly? All the videos I've watches just emphasize that you should tighten them by hand, it should be easy, and you shouldn't use any tape or caulking or anything.

Answer 1

Time to cut your losses...

As little as a new P-trap assembly costs, it might just be worth going to pick one up and replacing everything here.

As noted elsewhere, the metal nuts will chew up the plastic if they're not installed exactly correctly. Once that happens, the threads on the plastic pipe are toast and nothing will get them to be water tight.

Once you've got the new one, follow kreemoweet's instructions about installing all the joints loosely before tightening anything. I'd go so far as to suggest that once everything is connected, tighten each nut 1/2 - 1 full turn and work your way around to each nut before going back to the first one. Just to make sure everything has a chance to settle in nicely before one tight nut prevents the next joint from moving just that last little smidge.

Answer 2

First off, it's a bad idea to use metal slip-joint nuts on plastic drain parts which most certainly didn't come with metal nuts. Slip-joint nuts are not all the same, and are not necessarily interchangeable.

One trick to deal with a difficult joint is to leave ALL other nuts loose, so the drain parts have some wiggle, and then try to tighten the problem joint first.