slx m7000 Brake lever oil leak?- Mtbr.com
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  1. #1
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    slx m7000 Brake lever oil leak?

    Hello.

    The brake I use is slx m7000.

    Is there any leakage from the brake lever piston?

    It appears that oil leaks from the lever piston.
    And piston axis? Shakes differently from left lever.

    I wonder if the lever needs to be replaced, or should I have to do another maintenance?

    attach the photo and video.

    Thank you.

    https://youtu.be/_nNnvtukOPQ

    slx m7000 Brake lever oil leak?-kakaotalk_20180219_080202362.jpgslx m7000 Brake lever oil leak?-kakaotalk_20180219_080202638.jpgslx m7000 Brake lever oil leak?-kakaotalk_20180219_080203062.jpg
    Last edited by hibar; 02-20-2018 at 12:05 AM.

  2. #2
    Dave's not here.
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    Were they bled recently? Looks like some spillage that wasn't cleaned. Just looks like a weird spot for a leak. Though, the leak may have migrated to that point. Clean them well and monitor them for leaks.
    Yo no hablo inglťs

  3. #3
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    I am having a similar leak on my m8000 levers. Definitely juicing around the servowave cam and the lever pin, resulting in slow leaks on the levers. Cleaned them thoroughly and the leaks are reappearing. Rear is worse than the front. Thinking warranty time?

  4. #4
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    Same on my m8000s, rear is worse just like CP is experiencing. Might be the cause of my levers getting mushy after a few rides regardless of my bleed technique. CP, when did you purchase yours? Got mine new around 8 months ago.

  5. #5
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    Anyone reach out to Shimano with this issue yet? Iíve been cleaning and carefully monitoring the lever in that area so I can describe the issue clearly.

  6. #6
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    Hello.
    Leave feedback on problems with brake lever oil.
    Even if the oil was wiped off, the problem of oil spreading on the piston lever was still present.
    The brake fluid seems to ooze out a bit near the lever piston, and we replenished the oil again.
    Braking at rough down has not caused any problems yet.

  7. #7
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    Quote Originally Posted by jasonp22 View Post
    Anyone reach out to Shimano with this issue yet?
    Contact them for warranty replacement.

  8. #8
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    I've noticed that if I pressurize Shimano brakes using two syringes to bleed, they'll leak at the the lever or reservoir. I've chalked this up to the bladder cover distorting under pressure or there being a pressure relief built into the reservoir, depending on the type of reservoir. I believe those with the vented circular cap on the end of the reservoir (as pictured in earlier posts) have the relief valve. They were fine afterward. If the brakes are over filled with fluid, they make leak in the same way for a while. I think on some older levers there was an issue with the relief valve not sealing properly and continuing to leak.

    If I saw fluid at the lever after bleeding the brakes or putting in new pads, I'd rinse them off well by spraying with isopropanol and monitor them for a while. If they stopped leaking and the brakes kept working fine, I wouldn't worry.
    Do the math.

  9. #9
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    Has anyone solved this issue themselves?
    I have a m8000 lever that is leaking.
    It is NOT leaking from the end of the cylinder.
    Is is leaking from the green circled part on the first post.
    I have to top them off every couple of rides or keep moving the levers out which of course you can only do so much.

  10. #10
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    Have this same issue with my 3yr old m8000s and havenít been able to do anything about it. They usually need a top off / bleed every 2 weeks. Canít wait to toss them in the garbage.

  11. #11
    Elitest thrill junkie
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    Welcome to disposable shimano brakes. They don't make replacement parts, so you are just waiting till the thing catastrophically fails at the worst possible time. This is a big issue that I have with them and I definitely won't be buying any more. There are flaws that make them self destruct and nothing can last forever without some new parts, but shimano refuses to supply the spare parts.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  12. #12
    MTB brakes specialist
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    Titanium master piston that fits in all Shimano levers.
    Seals for that titanium master piston.
    Attached Thumbnails Attached Thumbnails slx m7000 Brake lever oil leak?-sans-titreasr.jpg  

    slx m7000 Brake lever oil leak?-sans-titrel.jpg  

    Attached Images Attached Images  

    Scott Genius 710 (2016)
    XTR Trail levers (BL-M9020) + XTR Trail calipers (BR-M9120)

  13. #13
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    How to disassemble

    Scott Genius 710 (2016)
    XTR Trail levers (BL-M9020) + XTR Trail calipers (BR-M9120)

  14. #14
    Trail Gnome
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    Quote Originally Posted by Groove_c View Post
    How to disassemble
    Thanks for posting that video

  15. #15
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    Hello. Did anyone resolve oil leak with replacing the piston?

  16. #16
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    Quote Originally Posted by MichaelDFC View Post
    Hello. Did anyone resolve oil leak with replacing the piston?
    It's not going to be resolved, you may get more life out of it, it'll eventually chew it up because the cylinder bore is cast, not machined.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  17. #17
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    and then what can i do? I don't want to replace my brakes.. :/

  18. #18
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    Quote Originally Posted by MichaelDFC View Post
    and then what can i do? I don't want to replace my brakes.. :/
    It might buy you time, it just won't solve the underlying issue.
    "It's only when you stand over it, you know, when you physically stand over the bike, that then you say 'hey, I don't have much stand over height', you know"-T. Ellsworth

    You're turning black metallic.

  19. #19
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    Quote Originally Posted by Jayem View Post
    It's not going to be resolved, you may get more life out of it, it'll eventually chew it up because the cylinder bore is cast, not machined.
    The master cylinder is aluminium, while the original piston is plastic. The plastic piston isn't going to wear out the cylinder as the piston is softer material. More likely is that the piston swells and gets stuck to the master cylinder and won't return properly, titanium piston won't have this(swelling) problem, but I haven't tried personally those titanium pistons so can't say if those are otherwise better/worse than the originals.

    It might also be that some dirt can seep between the two seals on the main piston, eventually causing the piston to get stuck and/or cause the seals to leak oil through. I just recently rebuilt two M8000 levers with this problem. Just cleaning the piston didn't solve the problem, I had to use some sandpaper & file to get the piston moving freely inside the main piston, so I suspect the piston had actually swollen for one reason or another. The seals were intact but there was a lot of dirt between them, so after cleaning and "machining" the piston, it moves freely and return spring returns it properly, no leak from seals.

    I'd recommend trying to "rebuild" the lever and see if that would solve the leaking problem, if there is just dirt on the master cylinder. Some "Slick kick" or other suspension grease for the seals when you re-assemble the lever and it should be good.

  20. #20
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    An update:I disassembled the lever and cleaned everything. I found dirty oil in the cylinder and on the piston. I cleaned all the parts as best I could. I also greased the piston with a little Vaseline. I assembled everything and for now everything is ok. I hope I don't see any more oil traces on the lever

  21. #21
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    Good stuff. Hopefully it's just dirty brake fluid that was causing the leak. How old are your brakes and when was the last full bleed?

  22. #22
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    3 years old. Last year

  23. #23
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    Quote Originally Posted by MichaelDFC View Post
    3 years old. Last year
    Guess it was sludge buildup in the piston area that didn't work free during the bleed.

  24. #24
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    Quote Originally Posted by Trinimon View Post
    Guess it was sludge buildup in the piston area that didn't work free during the bleed.
    I was wondering when rebuilding my levers, that is the normal bleed procedure(cup in lever, push new oil with syringe from caliper up) moving all the grey goo from deteriored/dirty oil from caliper to the main piston, where it eventually builds up and messes up the piston/seals. Hence the "gravity bleed" would be better, as that would push fresh oil from the lever towards the caliper and the grey goo wouldn't seep to the lever. The oil likely turns grey/black when it heats up in caliper under heavy braking and there might also be some dirt that enters the caliper from the caliper seals...

    Maybe two syringes would be best way to bleed, so that first push some fluid from caliper to lever, to get any air bubbles out from the lever reservoir, then push bigger amount of fresh oil from lever to caliper...

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