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  • Leaky XT caliper?
  • Premier Icon zippykona
    Full Member

    My front brake is now awful. It starts off ok but by the time of full braking it feels as if the calipers are flexing. No bite and no chance of stopping.

    Swapped disc,fluid and pads . Still bad.

    A look on the web shows lots of broken pistons.

    If it was leaking how much fluid would I see?

    I’ve covered them in talcum powder ,put the bleed block in and given them a good squeeze.

    Can’t see any damp powder anywhere.

    Any thoughts?

    Premier Icon P-Jay
    Full Member

    When mine went it didn’t take long to notice the oil on the caliper.

    Levers can leak too, and the seals collapse.

    Premier Icon joebristol
    Full Member

    It’ll either have a micro leak for the caliper or you’ll have an issue with a piston in the lever most probably.

    I’d just buy a new one to save a lot of faffing about – it’s ultimately what happens to quite a lot of Shimano brakes. Which is why my mtb’s don’t have Shimano brakes on them.

    That said I do have Shimano hydraulic road brakes as they came on the bike I wanted – they haven’t failed yet! These is a Hope caliper that is compatible with Shimano road brake systems though so when they self destruct that’s what I plan to replace them with 😃

    Premier Icon zippykona
    Full Member

    I guess one bad brake in 20 years isn’t too bad.

    Shame it’s an expensive one!

    Premier Icon ofked
    Free Member

    They can leak between the two halves of the caliper too. I didn’t see much fluid until I had it in bits. I’ve had two go (and some SRAM ones) and, same as you, tried everything and nothing fixes it.
    Easiest fix is new brakes. Never had trouble with hope’s but I did get some cheap zees for a bike I don’t use often.

    Premier Icon PimpmasterJazz
    Free Member

    Did you buy new? If you did ask the shop about recalls and/or warranty.

    Premier Icon zippykona
    Full Member

    Brakes are years old. Are the 4 pots more robust?

    Premier Icon PimpmasterJazz
    Free Member

    I’ve got both. I’ve had to bleed both, and be patient doing it (quick bleeds have been worse than useless – there’s always air left in the system). Two pots have been good for about four years (touch wood) and have been bled twice, but I’ve currently got an issue which appears to be a sticky brake lever on the rear 4-pot. Looking at it this weekend.

    Premier Icon zippykona
    Full Member

    Might stick the rear caliper with the front lever.

    Should be able to work out which bit is bad that way.

    Premier Icon zippykona
    Full Member

    Got home and gave them another squeeze and fluid spurted out of the round bit with holes in. Never noticed a leak from there before.

    Premier Icon argee
    Full Member

    You need to check the diaphragm in the reservoir, for that you will need to remove the lever from the bars, push the bit to open the lever up, then you can see a small grub screw that takes a torx key to remove, when you do this you can then remove that circular bit which has the diaphragm.

    From there check the inside of the rubber, make sure it’s all good, clean it up, refit it (quite easy, only goes in one way), then reassemble and rebleed the lever.

    Premier Icon joebristol
    Full Member

    Not sure if it’s a bad photo or if your lever is in a right state. Just buy a new brake – not worth messing about with. You could replace the lever now, but the caliper is then a ticking time bomb

    Premier Icon stevextc
    Free Member

    Got home and gave them another squeeze and fluid spurted out of the round bit with holes in. Never noticed a leak from there before.

    Was just going to post what argee posted.
    It’s meant to leak if the port is blocked… when did you last do a complete bleed and clean?

    Premier Icon zippykona
    Full Member

    Last bled yesterday. It looks a state as it’s covered in talcum powder!

    Wiggle had a complete brake for £66 , so gone with that option.

    Premier Icon argee
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    Good choice, use that one as spares now, can even do that strip of the lever to just get an understanding of the lever

    Premier Icon stevextc
    Free Member

    Last bled yesterday.

    and before that?
    What colour was the oil when you bled it?
    Immediate issue is likely a block in the port as Argee posted… the newer levers have the pressure release you discovered… (shocked the hell outa me when I found it by accident… but its worked for years after)

    longer term though if you don’t do full bleeds the dirt gets behind pistons (especially the master)… once that build up to the point it stops working you’re into a world of pain. (unless your idea of fun is even weirder than mine)

    Premier Icon stevextc
    Free Member

    can even do that strip of the lever to just get an understanding of the lever

    Or … Dry it out so the piston shrinks and clean it… leave it a while and repeat…keep going till you don’t get bits of black gunk.. you will be amazed how much gunk gets behind the master cylinder.

    Premier Icon Jordan
    Full Member

    @stevextc are they really meant to leak? Not saying I know otherwise, just been told different. I was told the diaphragm was to allow for expansion of the fluid but not supposed to let it out. I had one squirt when I pushed some pistons back while forgetting to open the bleed port and was told I had popped it.

    Premier Icon stevextc
    Free Member

    @Jordan

    Hmmm… given brakes are an important safety item I’ll reword that.

    I haven’t read the documentation or stripped a x000 series lever yet. (good sign I haven’t had to)

    I did however squirt a load out a long time ago now when the x0000’s were pretty new.
    MY first thoughts were “oh bugger….” but I cleaned it up and it’s working a couple of years down the line so I’d assumed the “new dimpled bit” is actually designed to work that way.

    Premier Icon Jordan
    Full Member

    @stevextc yeah, I had a look at the documentation and couldn’t find any mention of it. Would be interesting to know for sure.

    Premier Icon argee
    Full Member

    Funnily this thread did make me do a strip of an xtr lever i was saving for another build, there really isn’t much inside, the diaphragm/bladder attaches to the circular plastic plug that you can see the end off (which the oil can come out off), only way the oil will come out that port is if the pressure to push it through the piston is greater than the pressure required for the oil to push past the diaphragm into the plug and shoot out as you’ve seen.

    A strip is always good, dust/dirt/etc can get in over time, pretty easy to strip down, it’s just a faff working out where the two grub screws are, one of them is hidden behind a little rubber bung, but needs to be removed to get the lever off.

    Premier Icon Jordan
    Full Member

    @argee when you say that the oil can come out of it, do you mean there is a legitmate way for it to come out without it being damaged?

    Premier Icon argee
    Full Member

    Yeah, it’s all about the pressure in the reservoir, if something is causing a little more issue with the pressure required to work the piston, then it will build it up internally, below are a couple of pics of the internals that i had from the strip/rebuild.

    IMG-7651<br />download high quality pictures from instagram<br />

    IMG-7652<br />download high quality pictures from instagram<br />

    Premier Icon Jordan
    Full Member

    OK cool. Cheers for clearing that up!

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