I have an ABS pipe fitting under my kitchen sink which appears to be held on by friction (white piece just above the p-trap). After the p-trap the pipe makes a long run to the left where it's not really supported by anything. It seems the weight of this run caused the pipe to slide down off the drain pipe, causing a huge gusher.
I'm not totally sure how this is intended to work, but it seems like the white fitting just holds the p-trap and everything on by friction? If so, what should I do – replace the white piece? Anything else? Also, how do I know what the correct height of the fitting and slope of the lateral pipe should be. The lateral pipe was fairly level before, but a friend noted that ideally it should slope a bit. Not sure if I'll mess anything up by adding slope.
(Note: zip-ties in the pic are my temporary safeguard).
Best Answer
Unscrew the white compression nut and take a look at the sealing ring that is under it. These can get hard with age or over compressed and lose shape and thus lose its ability to squeeze tightly to the down drop pipe from the sink drain. If this is the case it is an indication that the sealing ring needs to be replaced.
The common type of the sealing ring is made of a nylon material whilst the orange colored one (purchased at big box store) is made of a more rubbery type plastic that will compress and squeeze much better under the compression nut. (In the picture I have cut the nylon part to show it's wedge shaped cross section). I have also seen the rubbery type wedge rings in a blue color as well. These better rubbery sealing rings cost more than the nylon types but are far superior in my opinion.
When you take apart the slip joint do take care to clean out the joint and the outside of the drop pipe to remove any old drain gunk and soap scum. A nice clean setup will result in the best seal of the wedge shaped sealing ring against the drop pipe.