Shimano XT M785 – Brake bleeding?

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  • Shimano XT M785 – Brake bleeding?
  • mr plow
    Member

    What kit do you require to bleed the XT brakes? I read they are now “one way” bleeding…?

    Worried I will buy the wrong kit for them. Also does mineral oil suffer from water absorbtion like Dot brake fluid?

    Cheers for your help. :mrgreen:

    Premier Icon tomaso
    Subscriber

    A bit of rubber tube is all you need to bleed the very similar Deore brakes – squeeze open close release repeat

    Superficial
    Member

    I don’t think mineral oil absorbs water – at least nowhere near as much as Dot5.1.

    As for bleeding the brakes, you’re supposed to buy a bleeding funnel. However a (non Luer lock) 20ml syringe jammed into the bleed port works just as well. Aside from that you need another syringe and some tubing.

    rwc03
    Member

    You need the funnel too, I think you might just manage it without but it will make life a lot easier and your less likely to get air in.

    Edit: Too slow

    Tube available from Pets at home. Clicky

    I also use the tomaso method. Very easy.

    Edit; Another clicky

    mr plow
    Member

    Thanks for the help. Have a good weekend ๐Ÿ˜€

    Rickos
    Member

    That ‘Another clicky’ link from Mulletus shows it to be oh so simple. I’ll have to give that a go on my SLXs.

    Superficial
    Member

    It’s not a difficult process but it’s an art to get a good bleed. I say art, but my success rate seems to suggest it’s more like pot luck. On the third bleed I got it working really nicely, can’t say what I did differently.

    That youtube video has a few good tips though – I’m definitely going to try the olive-over-the-bleed-hose thing, when the tube pops off the bleed nipple it’s very irritating.

    jruk
    Member

    That video is brilliant but what happens when you pull the syringe out of the lever end? I’m guessing it pi$$es everwhere and you screw the thingy back in?

    Anyone have a link to the vid for shortening the hoses? My rear hose is stupidly long so I need to trim it down. I’ve got a spare olive and a silver thing (insert?). What else do I need – I’ve got the oil and a couple of syringes.

    rwc03
    Member

    Have a search for the big thread on the xt brakes, someone did a nice picture guide. I got away without bleeding mine when I cut them down.

    jruk
    Member

    Thanks rwc. I’ve had a look but can’t find that thread – there seem to be loads. Do the hoses just unscrew from the lever? Not taken the plastic cover off as I’m not sure what’s under there!

    rwc03
    Member

    Hi jruk, yep they just unscrew, but they’ve been nipped up pretty tight so I clamped mine on a pair of old bars to undo. The plastic covers on the hoses are just help keep mud and other crap out. If you’re careful when you cut and don’t swing the bits around you should get away with not having to bleed.

    Here’s the guide:

    http://singletrackworld.com/forum/topic/psa-xt-m785-brakes/page/6

    Thanks again to DezB for doing that.

    Rickos – Member
    That ‘Another clicky’ link from Mulletus shows it to be oh so simple. I’ll have to give that a go on my SLXs

    Where can those syringes be had? The one that screws into the lever, in particular?

    Superficial
    Member

    They’re just standard (?) syringes – I know they’re a standard size for IV lines in hospitals – I think they’re the same ones people buy from Vets. The plastic’s fairly soft so it just deforms to the thread – if you’re offered a choice though, “Luer lock” ones won’t work.

    endorphinix
    Member

    Hi,

    my wife got a set of these a month ago and smashed the right lever on some rocks in a crash last week. I ordered a new lever and some oil, it is mineral oil but not shimano of CRC. I used the bleed instructions and seem to have filled the resevior, ( it did start comming randomly out of the side of the res at one point ) but the brakes are no where near as strong as the original rear. They dont seem to actuate as soon as the lever moves like the rear does. there is a slight delay.

    Bled and re bled all day, following al shimano guidelines and the ways mentioned on here. Anybody else experienced this lack of sharpness after a bleed. could it be inferior oil?

    cheers

    K

    solitone
    Member

    @jruk, that wrote:

    that video is brilliant but what happens when you pull the syringe out of the lever end? I’m guessing it pi$$es everwhere and you screw the thingy back in?

    You might insert the plunger into the barrel before pulling the syringe out. This way you wouldn’t leak oil.

    solitone
    Member

    Superficial wrote:

    That youtube video has a few good tips though – I’m definitely going to try the olive-over-the-bleed-hose thing, when the tube pops off the bleed nipple it’s very irritating.

    I also can’t stand it when the tube pops off the bleed nipple!

    But I can’t understand how I should use the olive. The olive is free to move up and down the tube. How can the olive keep the tube tight? Maybe it locks on the bleed nipple?

    perthmtb
    Member

    Yes, the olive locks over the bleed nipple, and is the same principle as the special Shimano clamp that comes with their bleed kit – see black plastic piece at bottom of this photo…

    But of course why buy the tools specially made for the job when you can cobble together stuff from a vet, hardware store, pets shop, and your spares bin, and bodge it.

    Sometimes I just don’t understand the mentality of us bike owners. We spend rediculous amounts of dosh on bits for the bike just because they are anodised purple, or weight 0.3 grams less than the perfectly good ones that came with it. But then when it comes to maintenance, and something as important as having brakes that work properly, we scavenge around anywhere to avoid buying the kit made for the job with all the parts that fit perfectly and make the job real simple. Yes, its slightly cheaper – but a litre of Shimano mineral oil only costs 14 quid and will probably last the life of the bike (or a few bikes), and the proper Shimano bleed kit above with everything you need costs all of 15 quid.

    Really, why all this reverse one-upmanship to see who can get away with the cheapest maintenance products not designed to do the job…

    solitone
    Member

    Yes, I agree. And personally I did buy the kit offered by Shimano.

    However I didn’t figure out that the special black clamp locks over the bleed nipple, like the olive.

    I wondered how I was supposed to take advantage of it, but I didn’t come up with any idea! ๐Ÿ™‚

    So, thanks for your hint! I’ll try it next time (my first attempt at bleeding was far from perfection!)

    BTW, why is the black clamp so long? Does it lock somewhere over the caliper, as well as the bleed nipple?

    Thanks again

    mr plow
    Member

    I have had best bleeds on all brakes by taking the brake off the bike and hanging then vertically with calliper at bottom. Mega bleeds on XTs, OROs and Hopes using this method and moving the caliper about a bit to knock any air out of caught spaces into the line and up to the lever. ๐Ÿ™‚

    Premier Icon Pridds
    Subscriber

    Neat solution, i’ll be buying one of them next time my brakes need bleeding.

    perthmtb
    Member

    BTW, why is the black clamp so long? Does it lock somewhere over the caliper, as well as the bleed nipple?

    Nah – it’s just a long handle to make it easier to push the thing over the bleed nipple to secure the hose, and remove it after. In fact, that’s the main problem with the olive workaround – its too fiddly!

    Premier Icon edd
    Subscriber

    Personally I wonder why people don’t buy the funnel, it’s ยฃ3.99 so hardly expensive.
    http://www.chainreactioncycles.com/Models.aspx?ModelID=34710

    The easiest way to bleed is to follow Shimano’s excellent instructions.
    http://techdocs.shimano.com/media/techdocs/content/cycle/SI/Deore-XT/SI_0116A/SI-0116A-001-00-Eng_v1_m56577569830746864.pdf

    Premier Icon chainslapp
    Subscriber

    +1 for Epic Bleed Solutions. I’ve used their kit on a number of 2012 Shimano brakes and its really easy to use.

    Superficial
    Member

    This thread is 9 months old…

    Really, why all this reverse one-upmanship to see who can get away with the cheapest maintenance products not designed to do the job…

    It’s more to do with the fact that people resent being ripped off. Avid bleed kits are ยฃ42 or something stupid for two syringes and a bit of plastic tube. It’s sheer profiteering and we shouldn’t accept it.

    The Shimano bleed nozzle thing for ยฃ4 is a different matter I guess.

    Scamper
    Member

    Regarding the Shimano instructions, I have found that the last step of rotating the lever 30 degrees back and forth always seems to get the last air bubble out of the reservoir.

    Is an indication of a good bleed, turning the bike upside down, then the right way, and pressing the brake lever ie poor braking would be an indiation of air usually trapped in the reservoir flowing into the system when up side down?

    andyrm
    Member

    I’ve filled and bled XT and Zee brakes using the funnel & syringe as per the instructions.

    One top trick though (taught to me by a bl**dy good mechanic and DH racer) is that once you have completed the bleed process, you can “trick” the caliper into thinking there is a bit of pad wear, and so get a more positive bite point feel.

    To do this, take out the bleed block and put pads in, then put about 1cm of fluid into the funnel, slowly pull the lever once (with lever at horizontal position and nipple on caliper CLOSED) and release. Then close off funnel and bleed cap, insert wheels and away you go. Helps remove the very last little bubbles and ensures a really good lever feel.

    solitone
    Member

    This thread is 9 months old…

    Yes, still interesting though.

    once you have completed the bleed process, you can “trick” the caliper into thinking there is a bit of pad wear, and so get a more positive bite point feel.

    To do this, take out the bleed block and put pads in, then put about 1cm of fluid into the funnel, slowly pull the lever once (with lever at horizontal position and nipple on caliper CLOSED) and release.

    How much do you pull the lever?

    andyrm
    Member

    Pulling it about half way seems to work best ๐Ÿ™‚

    solitone
    Member

    @andyrm: your trick rocks!

    I bleeded my BR-M785 system a couple of times in the last few days, but always ended up with the lever having too long travel for my taste.

    So I followed your suggestion, and now I have the right travel!

    The only thing, I needed to pull and release the lever several times, pulling it almost all its way (I put and took out the wheel several times to check). But my pads weren’t new, so I did have some pad wear, and this might have been relevant.

    Scamper
    Member

    The levers on my M596 Deore were pulling very close to the bar I presume due to pad wear? So tried that trick above pulling the lever fully in twice and its worked a treat. Pads have adjusted themselves to the caliper and if anything the modulation seems to have improved too. Will this effect the servo-wave though?

    solitone
    Member

    Scamper wrote:

    Regarding the Shimano instructions, I have found that the last step of rotating the lever 30 degrees back and forth always seems to get the last air bubble out of the reservoir.

    That’s true. As well as the the step before, of pulling the lever, opening and closing the bleed nipple for half a second, and releasing the lever.

    These last two steps require much patience. I repeated them tens of times, and few little tiny bubbles seemed to never end. Overall the extra amount of air that I managed was little though, as those bubbles were few and small. I don’t know whether such perfectionism makes any noticeable difference.

    andyrm
    Member

    Nice one guys! Glad it helped ๐Ÿ™‚

    Doesn’t seem to affect the way the servo wave comes “on cam” in any way either……..

    Pity they don’t show this in any of the guides eh?

    bigyinn
    Member

    I don’t think M596 have servo wave do they?

    cienega
    Member

    Here’s the guide:

    http://singletrackworld.com/forum/topic/psa-xt-m785-brakes/page/6

    Great guide, thanks for reposting.

    Slight departure from the main discussion, but does anyone have any experience of cutting Shimano hoses and installing the olive / insert without a vice / yellow hose clamp (missing from my new m596)?

    solitone
    Member

    Yes andyrm, it’s curious such info is in no official instruction!

    you wrote:

    take out the bleed block and put pads in, then put about 1cm of fluid into the funnel, slowly pull the lever once (with lever at horizontal position and nipple on caliper CLOSED) and release.

    Wouldn’t this work after tightening the bleed screw as well?

    I mean, you close the caliper, tighten the bleed screw, remove the bleed block, put pads in, and pull and release the lever.

    What’s the point of having the funnel with oil installed? Does some oil enter into the system when the lever is pulled?

    andyrm
    Member

    Yeah it lets a tiny amount more fluid in and also acts to protect against risk of air ingress.

    Someone far cleverer than me when it comes to fluid systems could probably explain why – all I know is it makes Shimano “new style” brakes loads nicer!

    ๐Ÿ™‚

    slimporcini
    Member

    so glad to hear about this trick. Thank you very much Andyrm. Brakes are feeling well sweet now! ๐Ÿ˜€

    robarnold
    Member

    One top trick though (taught to me by a bl**dy good mechanic and DH racer) is that once you have completed the bleed process, you can “trick” the caliper into thinking there is a bit of pad wear, and so get a more positive bite point feel.

    To do this, take out the bleed block and put pads in, then put about 1cm of fluid into the funnel, slowly pull the lever once (with lever at horizontal position and nipple on caliper CLOSED) and release. Then close off funnel and bleed cap, insert wheels and away you go. Helps remove the very last little bubbles and ensures a really good lever feel.

    This is the best piece of advice I’ve heard in ages, just done the same to my 785s and they feel brilliantly positive with short lever throw again. I was only thinking on today’s ride that they were getting a bit close to the bar, although they’ve always stayed sharp despite this. Now they are like throwing an anchor out the back with minimal lever throw, just as they should be ๐Ÿ˜€

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