Dodgy waste pipe connection

[pmx_super]

I've just removed the kitchen sink u-bend and the connection to the 43mm (OD) waste pipe drain looks to be a right dog's dinner. The end of the waste pipe isn't cut cleanly, and the white threaded connector that was on there doesn't grip at all. There appears to be black gunk where the O-ring is, almost as if the cavity was filled with black silicone glue. Is that a valid method!?

How should a U-bend be connected to a 43mm unthread waste pipe? Will I need to clean up the cut end, or can I get a compression seal around the outside of the pipe?

 

[Wayners]

McAlpine Adjustable Inlet Bottle Trap White. Might work as is but you may need to replace part of that solvent top bit with a joints and a bend or two.
DIY sell short pipe and beads

 

[pmx_super]

McAlpine Adjustable Inlet Bottle Trap White. Might work as is but you may need to replace part of that solvent top bit with a joints and a bend or two.
DIY sell short pipe and beads

So I guess the magic part there is the multifit connector on the outlet? If I just want to reinstall the U-bend do you know if there is a 90 degree elbow which is "multifit" one end and "normal" (screw up compression type) on the other?

 

[Wayners]

You need a u bend or bottle trap. I mean p trap...
You saying your current p trap won't line up?

 

[pmx_super]

You need a u bend or bottle trap. I mean p trap...
You saying your current p trap won't line up?

It lines up but I just can't get a good connection to the solvent weld cut end.

 

[pmx_super]

Feels like I need one of these only with a threaded end where the coupling nut is

T5M-A 95 Degree Multifit Bend X BSP Coupling Nut 1½

Manufactured in Polypropylene

www.macdonaldplumbingsupplies.com

 

[pmx_super]

Just realised that the existing elbow shown in my first post is mcalpine multifit. So how are these supposed to make a seal? I feel like mine is missing a rubber seal, or it's become stuffed down into the fitting.

 

[oldbuffer]

1. Looks to me as if the 90 degree elbow is missing its sealing ring.
2. The black pipe should have (from black elbow towards open end):
2.1 The white knurled nut from the white elbow.
2.2 The orange coloured plain washer from the white elbow.
2.3 A black rubber sealing ring. E.g. McAlpine RWM2. Narrower end of tape towards white elbow.
3. Worth cleaning up the black pipe with something like Scotchbrite, but probably OK without.

 

[pmx_super]

1. Looks to me as if the 90 degree elbow is missing its sealing ring.

Is this it, stuffed down inside the fitting, or is there a second rubber in there too?



I'm wondering if Mr muscle sink unblocker could have dissolved the rubber, hence the black goo at the end of the pipe? Unblocking the waste pipe is why dismantled it in the first place.

 

[oldbuffer]

Looks like the seal. Try fishing it out with a hook of some sort (old wire coat hanger cut and bent?) and see if it can be re-used.

 

[Hugh Jaleak]

Need to hook that black rubber washer out first and check its condition. If in any doubt, replace, pack of O Rings less than £3. https://www.screwfix.com/p/floplast-40mm-replacement-trap-seal-4-pcs/40512 You need the red plastic ring and thick rubber washer, the big O ring is for middle of a Bottle trap, so discard. (Smaller O ring is for joints in P/S traps, might be prudent to replace the seal where you've undone your trap before reassembling.)

Slide Plastic nut, then Red O ring, then Tapered rubber washer onto the spigot of your waste paste, taper needs to be facing the trap, as its this that makes the seal. Offer trap back to outlet, making sure it's pushed as far on as it'll go, if need be slide the plastic nut and washers across to meet the trap, you want as much of the spigot inside the socket of the compression fitting as possible. Tighten nut, refill trap and test.

 

[pmx_super]

Thanks for the help everyone. I fished out the washer and it was a very mangled version of the thing Hugh linked above. When I followed your installation instructions I could get a water tight seal, but will get a couple of spare washers anyway because that thing really shouldn't have been reused.