New disposal is larger than old one. It's hard to see in the photo, but the existing pipe (the one with the timestamp on it) is about 2" too long.

However the too-long pipe is glued together with other elbows and joints, so replacing this seems troublesome. Or maybe I'm overestimating the difficulty there?

Maybe if I brute-forced it I might be able to might be able to move the pipes far enough to get it to fit, but it feels like it would break something. Do these things break under much stress or is it worth a try? Or is it better to replace the whole thing for a better fit anyway?

Or, is there any way to unglue and just replace / cut / modify that middle pipe? What should I do here?

Update: I did brute-force it, but the resulting connection was so wonky that even with the ring clamp it leaked all over. So that's not an option.


  • Photo link is broken.
    – brhans
    Commented Aug 9, 2020 at 15:32
  • @alaska man the photo in your link looks different than your description I think, different name?
    – Ed Beal
    Commented Aug 9, 2020 at 15:42
  • Unfortunately, we'll need more info (including a good picture) before we have any chance of helping you. Please take our tour so you'll know how best to participate here. Commented Aug 9, 2020 at 16:23
  • Not sure what "Photo link" is referring to. It's a link to another DIY question and it works on my end. It is to provide reading on plumbing a disposal.
    – Alaska Man
    Commented Aug 9, 2020 at 17:35

1 Answer 1


However the too-long pipe is glued together with other elbows and joints, so replacing this seems troublesome.

That is why it is not standard practice to use glued ABS piping under a sink. You can not un-glue the joints, it must be cut out and replaced. You should have removable slip joints.

Your P-trap is on the wrong side for your set up.

On the left hand sink you should have tee connected to the tailpiece that is on the drain basket. That tee accepts a tail piece coming from the disposal, the P-trap is attached to the bottom of the tee and then goes to the sanitary tee to drain.

You need to cut out the sanitary tee just under where it is glued so you can glue a new one on.

Your air admittance valve on top of your sanitary tee is too low, it should be at least slightly higher than the sink drain but optimally as high as you can get it in the space between the sink and the cabinet.

This YouTube video will illustrate the set up, minus the air admittance valve.

  • I don't think I want to get that deep into it. Exploring my options, it looks like there's a flexible coupling thingy for $4. If I cut some of the middle out of the long pipe and couple it back together, would that suffice? Or should I just replace the whole thing?
    – Dax Fohl
    Commented Aug 9, 2020 at 1:28
  • @DaxFohl Those flexible pipes are magnets for collecting debris. (especially from a disposal) It is not difficult to do it right and will be more easily serviceable in the future.
    – Alaska Man
    Commented Aug 9, 2020 at 17:38

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