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  1. #1
    undercover brother
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    Shimano M785s leaking at Master Cylinder?

    I installed my new m785s the other night. I had to cut the lines and bleed them, that went well. However, there seems to be a leak in the cover on the master cylinder where the lid meets. After the inital bleed is was oozing out every lever pull, then slowly started decreasing. I pulled them this morning before I headed to work and a tiny, tiny amount still came out. The levers feel great, but is this normal?? I can't find anything on this. The other brake seems to be working just fine, no leaks except for the initial superfluous oil. I can also hear a small amount of a suction/release in the initial lever pull by where the leak seems to be occurring.

  2. #2
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    Check the bolts holding down the cover and make sure both of them are snugged down. I've seen a set of M596 brakes (same cover design) with a similar leak, it went away after I tightened down the torx bolt near the hose end of the cover.

  3. #3
    undercover brother
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    Quote Originally Posted by aerius View Post
    Check the bolts holding down the cover and make sure both of them are snugged down. I've seen a set of M596 brakes (same cover design) with a similar leak, it went away after I tightened down the torx bolt near the hose end of the cover.
    Do you know the size of the torx bolt, I have all the torx EXCEPT THAT SMALL SIZE!? It seemed tight, but I'm maybe thinking that I will loosen then retighten. Will all the oil come spilling out if I do this?

  4. #4
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    The torx bolt should be a T-10. I just went to my friend's shop to test it out, that's what it is on the M596 and SLX brakes. They didn't have a bike with M785 brakes on it to confirm it but I'd imagine it should be the same. You can loosen it about 1-2 turns without any oil spilling out, more than that and I can't guarantee anything.

  5. #5
    El CicloPath!!!!!!!
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    I've read that it is normal...its built in overflow. Mine did that when I cut the lines and rebled....but that lasted a day or two and its been perfect since.


    The oil will not come "splling out" If there is too much fluid, a few drops might seep out.

    I did have a mishap on my first attempt at resizing the hoses. When installing the cable to the lever witht he new olive, I did not properly seat the new olive correctly and got oil seeping out of the cable lever junction. I had use another new olive and rebleed, but that was not difficult to do at all.

  6. #6
    undercover brother
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    The rear will not stop seeping. I contacted shimano and will be sending them back for warranty.

  7. #7
    screamer
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    Tangaroo: Did you ever have a resolution to this issue? My XT 785s just started doing this while I was bleeding them, and continues to seep with every lever pull. I'm giving Shimano a buzz in the morning, but just curious to hear what your experience was. Thanks!
    On heavy rotation: White Lung: Deep Fantasy

  8. #8
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    I have the same issue. Id like to hear what the resolution is.

    Sent from my SPH-L710 using Tapatalk 4 Beta

  9. #9
    undercover brother
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    Quote Originally Posted by budgie View Post
    Tangaroo: Did you ever have a resolution to this issue? My XT 785s just started doing this while I was bleeding them, and continues to seep with every lever pull. I'm giving Shimano a buzz in the morning, but just curious to hear what your experience was. Thanks!
    The brake was warrantie by Shimano, and I have had zero issues since. Once you get these things working properly, they are amazing.

  10. #10
    screamer
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    Thanks!
    On heavy rotation: White Lung: Deep Fantasy

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