Loosen the other slip joints, and then go back and tighten the swivel first.
The swivel gets snugged up first, and then you can tighten the other two.
I'm getting a slight leak where the tailpiece joins the j-bend. The diagram on the packaging doesn't show a washer in this location - it's just plastic on plastic. Do I need to tighten more, or use some kind of sealant?
I think you need a washer, regardless of what any diagram shows. I've seen wall tubes (trap outlet tubes) that had molded-in round
edges to match the mating end of the J-bend, but never any such thing where the tailpiece gets connected. Just to make sure we're on the
same page, the "tailpiece" is the vertical tube piece that gets connected directly to the sink outlet.
I was referring to the tailpiece as the PVC part that goes into the drain pipe in the wall. I did as Terry suggested and the leak stopped.
The tailpiece is the pipe that comes down from the sink into the trap. The piece to the wall is a "wall bend". When you give the wrong name, we can only assume you know what you are talking about and give an answer to that.
Licensed residential and commercial plumber
Although this will cause wailing and gnashing of teeth, I sometimes put plumbers putty in the groove of the swivel. Not too much.