leaky compression joint: to diy or not? (plumbing)

Discussion in 'CycleChat Cafe' started by Dan B, 12 Dec 2017.

  1. Dan B

    Dan B Disengaged member

    The pipe to the cold water tap in the downstairs toilet has recently developed a slow leak (one drip every few seconds). How difficult is this going to be to fix myself? I know where the stopcock is, I can take a bike (or a computer) apart and reassemble it correctly, but I have never plumbed before and I overthink drilling holes in walls ("but how do I know there isn't a radiator pipe behind this?") to the extent that I never even put shelves up.


    What would a plumber charge?
  2. Brandane

    Brandane Fair weather cyclist.

    That wee silver screw on the pipe below the joint is an isolator, so turn it 90 degrees to cut off the water supply. Then you can take the joint apart, and use some PTFE tape when putting it back together. Sorted!

    Edit to add ...... The PTFE tape wraps around the threads on the joins when re-assembling. Wrap it the same direction as the nut is going to turn on the thread, so that you're not unravelling it as you turn the nut - if that makes sense.
    Last edited: 12 Dec 2017
    classic33, Dan B, Lonestar and 3 others like this.
  3. You're far better wrapping it around the olive inside, as that's where the seal is made. The threads simply hold the olive to the seat. Be careful not to over tighten, as you can make things worse.
  4. Phaeton

    Phaeton Guru

    Oop North (ish)
    That also looks like a plastic pipe, make sure it has an insert
  5. BoldonLad

    BoldonLad Über Member

    South Tyneside
    Be aware, looking at the photograph, I would say the small silver screw head in the silver part, is to isolate the water supply to the tank (to allow work on flushing mechanism etc). In order to remove mains pressure before the isolator, I would suggest you turn off the water supply at the stop-cock. Will not do any harm, and, better safe than sorry (and very wet) ;)
    raleighnut, Cycleops and Dan B like this.
  6. Globalti

    Globalti Legendary Member

    I would start by gently nipping up that locknut while holding the body of the valve firmly to prevent it from turning. Do not overtighten it if that's plastic pipe. If that doesn't stop the leak, I would turn off the water at the main stopcock, unscrew and and do as advised above with some PTFE tape. And no, I would NOT turn off using that isolator because the damned things always seem to leak when disturbed, especially if you put any pressure on the screwdriver while turning the ball.
    Dan B likes this.
  7. screenman

    screenman Legendary Member

    Of course everybody checks their stop cock on a regular basis, don't they. Every house I have bought or been involved with doing up has had a faulty stop cock, when you need it to work and it does not you tend to think blast or words to that effect.

    For the few bob the cost I would replace the vales whilst I was playing about down there.
    raleighnut, slowmotion and Dan B like this.
  8. woodenspoons

    woodenspoons Über Member

    North Yorkshire
    Around £90 up here in North Yorkshire to take apart and refit.
    You're in London, so you may have to sell your best bikes, and a kidney.
    If you do try yourself, take the advice above. Don't overtighten. You will split the plastic pipe. And check the plastic pipes all have inserts to strengthen the ends where they meet the fittings. Plastic can leak in the joint if the pipe was badly scratched when fitting. PTFE might do it, at a pinch.
  9. slowmotion

    slowmotion Quite dreadful

    lost somewhere
    It's a very simple job and you can easily do it yourself. Where are you in London? You can borrow the tools from me if you want.
    classic33 and User1252 like this.
  10. slowmotion

    slowmotion Quite dreadful

    lost somewhere
    If there's no insert, the olive has almost certainly been over-tightened. You won't get an insert in retrospectively, so it means that the short length of plastic pipe will need replacing. None of it is a big deal.
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