Kitchen Sink, trap keeps slipping off drain pipe?

There should be a white nylon beveled washer on the tail pipe. The low edge of the washer should aim into the fitting so it is wedged snug by the nut. If it is installed backwards it won't hold. If it is damaged or missing, you can pick one up at your favorite hardware store for a few cents.

If the pipes are plastic they could be cross threaded even if its metal is still can be cross threaded from over tightening The washers are held in place by the cap your tightening if installed backwards you will not be able to screw the cap more then a thread or two. Also If the pipes are dirty those washers can slip down Since drain pipes have no water pressure just gravity feed even if you tighten all the way you can still pull the pipes down. If the pipes or washers are worn old dirty buy new one you can get the wall arm P-trap and the straight pipe in a kit at home depot with all washers included. for few bucks city dependent

Plumbers tape also known as Teflon tape, is used on the threads to aid in sealing and to keep metal on metal parts from rusting together what your stretching it across to is a mystery. Your washers should have a tapered edge that taper goes towards the pipe not the screw cap when screwed together the washers are pressed into either side of the P- Trap the wall arm has a flat edge washer called a {T} washer it looks like a {T} They are all plastic and don't last for ever in most cases. Also they come in 2 sizes 1-1/2 to 1-1/4 n my state the kitchen sink is 1-1/2 Generally the smaller of the two belong in the bathroom. Ive included the link to home depot in my state for the cost of the entire assemble the cost vs hassle of clean up plus wrecking the cabinets wood not to mention future mold is well worth it. Also my personal preference is the PVC vs Metal they allow More flexibility vs metal which don't and metal is more expensive and don't last as long.

hope that helps

Lr

hope that helps

Lr

1

Sink Pipe

Those great plastic pipes they use now? Yeah, ours feel apart several times just like yours. . . . the final straw was when we heard a crash, went into the kitchen in time to see the disposer rolling across the floor.

We told the plumber not to bother showing-up unless he brought some METAL pipes that would hold together - no problems since.

Yes, there should be a tapered washer that seals even tighter as you tighten the nut, but I go a step further, Put silicone all around that washer it'll seal and stay sealed long before the nut starts to crack

There should be a round wedged washer mostly white but some are clear should fit snugly around tail pipe with wedge facing down. Your hardware guy will have these