Fixing leaks to pipes under sink

• https://homeguides.sfgate.com/fix-pipes-come-loose-under-sink-31304.html
• https://www.hunker.com/13417096/how-to-install-slip-joint-washers-in-plumbing
• https://youtu.be/1b0asFPDzfA
• Notes:
  • you need a rubber gasket (= washer in UK)
  • for your slip joint nut (= compression joint in UK)
    • 1.5” / 40mm
  • and a nut
  • and maybe a length of pipe (also 1.5” / 40mm).
• What we did:
  • We bought a “cistern flush pipe coupling rubber conical washer seal” (see photo) from eBay, and used it to replace the previous one, which was rounded and had a uniform width (instead of tapered). This fixed the loose joint under our kitchen sink (early 2021).
  • We also bought one of these (see pic), which was a “McAlpine T12A-3 1½” BSP Coupler White 40mm x 40mm” from Screwfix. The diagram shows how it would have worked if we’d needed it, but actually the replacement washer seems to have done the job.

Installing a new kitchen mixer tap

When the pipes look like this…

• Extra advice based on experience (see also advice from friends below):
  • This video is really good
  • Turn the water off at source first, in case of error
  • Make sure you clamp the bottom nut to hold everything still while you turn the top nut
  • The olives may not come off and you may need to cut the pipe - in which case you can use a small tube cutter - only cost me £10 and worked like magic!
• Advice from friends:
  • “Turn the screw 90 degrees and it’ll isolate the valve, then you can detatch the top bit. They’re called isolator valves if you need to Google.”
  • “No welding required, those are compression joints and the bit in the middle is a valve. Turn the valve with a screwdriver to turn off water to the pipes coming off the tap, loosen the nut and the pipe should come out with that bronze bit (called an olive) round the outside near the end of the pipe. It’s possible whoever fit it also put some tape/putty other stuff round the joint but you really don’t need that with compression joints. If the olive won’t come off the pipe or it’s a bit bent then just buy some more, cost next to nothing. “
  • “the key lesson with them is to not over-tighten when you’re doing it back up.”
  • “it’s an isolator valve with compression joints on the ends. Depending on how your new tap fits it might need that same copper pipe into it or it might have flexi pipes that just screw onto the top of the isolator valve, no olives or other bits needed. “
  • “Also a top tip - If you are installing a tap from Grohe, Germans use valves that are based on metric rather than imperial measurements and are ever so slightly differently sized from standard UK plumbing so you need an adaptor. Fine for going into compression joints, not fine for screwing onto things like isolator valves.”