XT brake bleed question…

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  • XT brake bleed question…
  • Premier Icon Alex
    Subscriber

    Santa didn’t bring me the oft-requested bike maintenance skills 😉 Using the funnel + bottle approach. I know it works as I’ve seen my mate do it many times. Front is a triumph. Rear, well that’s not good at all even doing EXACTLY the same!

    So
    – wind adjuster all the way out
    – wind servo wave screw all the way out
    – remove reservoir screw on brake and screw in Shimano funnel thing. Leave bung in
    – remove pads, stick yellow plastic bung in to stop pistons moving (hah, like that’s going to happen!)
    – Attach tube (which finished in a sealed bottle) to rear bleed screw
    – Crack open bleed screw 1/2 turn it
    – remove plug from funnel.

    Fluid flows for a bit then stops, pump lever, more fluid comes out and then straight back in once lever is released. Checked all connections are tight, there’s not much air being pushed through but lever comes back to bar and pistons not moving even with bleed screw closed.

    Tried
    – doing the old Hope/Car thing of squeeze, close bleed screw, release lever, open bleed screw
    – put it all back together and start from scratch
    – Syringe at caliper end with fluid in to try and bleed any air
    – not opening bleed screw as much as maybe air is getting in there
    – shouting at it and stroking the big hammer to show it what might happen if it doesn’t get its act together.

    Whatever I do, as soon a the lever is released, the fluid rushes back into the caliper. If I put pads back in they move a bit but not enough to grab the disc.

    Any ideas, before I admit defeat short term and shove a working brake off another bike on there.

    crosshair
    Member

    Have you released all the hose mounts and disconnected the caliper so its hanging nice and straight down with the caliper right at the bottom? It’ll be the tiny bubbles causing trouble. There was a good thread fairly recently….

    jimw
    Member

    Normally, you partially fill a syringe with fluid , attach to bleed screw, attach funnel at the top, pull out bung and then force fluid up from the calliper till bubbles stop, then allow fluid to drain the other way, topping up with fluid in the funnel as necessary. Close bleed screw, then move the lever to different angles and flick lever to get rid of bubbles in the master cylinder. Then put un bung and remove funnel.

    Premier Icon Alex
    Subscriber

    Thanks all, I’ve had a beer to quell my hammer twitch! I did try the syringe thing (using a bastardised reverb service kit) but seemed to get more fluid on the caliper than into the hose!

    I’m going to go ‘dangle my caliper’ now. That thread was useful. Ta.

    Premier Icon deets
    Subscriber

    Having just spent an hour in the man cave arising about with mine, I reckon it’s a bit of a black art… I’m never happy with having to pull the lever nearly to the bar to get good braking, like there’s not enough fluid in there. I’ve been experimenting with the method of removing the bleed block or pad spacer and squeezing the lever so the pads move further in, then top the reservoir up and close.

    The thing is, despite doing exactly the same with each end, the front brake has been much more successful than the rear!

    Premier Icon Alex
    Subscriber

    Yeah I know that feeling. However after some caliper-dangling, the rear is almost as good as the front, fixed it straight away. I also top up the res after taking the block out and putting the pads in.

    Thanks STW hive mind.. ready to go to Wales without wondering if I have any brakes!

    Premier Icon JoeG
    Subscriber

    If there is some air left in the system, this will get rid of it after it has migrated up to the master cylinder (lever).

    http://www.pinkbike.com/news/tech-spotlight-5-minute-bubble-bleed-2014.html

    Hob Nob
    Member

    Follow the Epicbleed method. It’s given me the most consistent results 🙂

    Here’s our bleed guide:

    http://www.epicbleedsolutions.com/blog/how-to-bleed-new-shimano-brakes/

    See how you get on with that. If you have any questions you know where I am.

    Premier Icon tillydog
    Subscriber

    Alex – Member
    doing the old Hope/Car thing of squeeze, close bleed screw, release lever, open bleed screw

    IMHO, you’ve got that sequence wrong – should be: squeeze & hold, open bleed screw gently & let fluid out, close bleed screw, release lever.

    It will stop this:

    Whatever I do, as soon a the lever is released, the fluid rushes back into the caliper.

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