Results 1 to 21 of 21
  1. #1
    g3h6o3
    Reputation: PissedOffCil's Avatar
    Join Date
    Oct 2007
    Posts
    3,708

    Shimano M985 - Auto retract too far?

    Hello,
    I worked on my XTRs 2 days ago. The pads had some dirt baked on them and weren't giving me the usual power so I removed them and sanded them. When putting them back in I pushed the pistons back a bit and then reinstalled everything. When I pulled the lever, I could bring it all the way to the bar. I figured the pads we're positioning themselves so I kept on braking but they never returned to their original position to get the feel I like. I had to remove the wheel and pull the brake a couple of times to get a decent lever pull.

    Anybody else having the same behavior? The brakes are strong and consistent and have been recently bled. I'm very confident there is no air in the system. What could cause this? Dirty/sticky pistons?
    Check out my SportTracks plugins for some training aid software.

  2. #2
    g3h6o3
    Reputation: PissedOffCil's Avatar
    Join Date
    Oct 2007
    Posts
    3,708
    Bump... anybody got this behavior?
    Check out my SportTracks plugins for some training aid software.

  3. #3
    Picture Unrelated
    Reputation: zebrahum's Avatar
    Join Date
    Jun 2005
    Posts
    4,980
    That's normal. The pistons self adjust for wear and when you pressed the pistons back in all the way you need to pump them back into position. If your brakes didn't do this your lever throw would change when the pads wear.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  4. #4
    g3h6o3
    Reputation: PissedOffCil's Avatar
    Join Date
    Oct 2007
    Posts
    3,708
    I guess you didn't understand the question.

    I had to remove the wheel to get the pistons to get back to their original position. Unless I removed the wheel and pumped the lever a couple of times, they retracted too far away and my lever got almost all the way to the bar.

    Never had to do this before with other brakes. Could it be due to the ServoWave maybe?
    Check out my SportTracks plugins for some training aid software.

  5. #5
    mtbr member
    Reputation:
    Join Date
    Oct 2009
    Posts
    19
    Most probably due to air in the system. I would take it to a good quality LBS and get em to bleed it.

  6. #6
    Picture Unrelated
    Reputation: zebrahum's Avatar
    Join Date
    Jun 2005
    Posts
    4,980
    Quote Originally Posted by PissedOffCil View Post
    I guess you didn't understand the question.

    I had to remove the wheel to get the pistons to get back to their original position. Unless I removed the wheel and pumped the lever a couple of times, they retracted too far away and my lever got almost all the way to the bar.

    Never had to do this before with other brakes. Could it be due to the ServoWave maybe?
    You're not helping much with your description. To me it sounds like you keep saying that you took the wheel off, pushed back the pistons, and needed to pump up the lever to get the pads not to retract. Eventually with pumping the lever the pads started working properly?

    That's normal.

    If this isn't the case, push the pistons back into the caliper, flatten the lever on the bar so the fluid opening is flat, open the reservoir cap and bladder, and fill that thing up to the top. Put the bladder back in (you'll loose some fluid) and put the cap back on and try it again.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  7. #7
    g3h6o3
    Reputation: PissedOffCil's Avatar
    Join Date
    Oct 2007
    Posts
    3,708
    No here is a step by step description

    1- Removed the pads, sanded them, put them back in
    2- Pushed the pistons in slightly
    3- Put wheel back in
    4- Pulled the lever expecting it to go to the bar until the pistons got back at their position
    5- After many pulls I realized the pistons weren't getting any closer to the disk and I didn't get the lever throw I like.
    6- I removed the wheel
    7- Pulled the levers a couple of times so the pistons get closer to the disk
    8- Put the wheel back in and got the proper lever throw

    The brakes are perfectly bled, this is not the problem for sure. The lever is firm and consistent. I can hang the bike upside down and pull the lever and it remains firm. I'm 100% positive there is absolutely no air in the system.
    Check out my SportTracks plugins for some training aid software.

  8. #8
    g3h6o3
    Reputation: PissedOffCil's Avatar
    Join Date
    Oct 2007
    Posts
    3,708
    Hum.. I just got this idea. Maybe it's the free stroke adjustment screw. The reviews I read and the experience I got is that it doesn't change much but maybe it changes how far the piston retracts... Since you need to push the pistons back in to see the effect, it can mislead people to think it doesn't do much...
    Check out my SportTracks plugins for some training aid software.

  9. #9
    Picture Unrelated
    Reputation: zebrahum's Avatar
    Join Date
    Jun 2005
    Posts
    4,980
    Quote Originally Posted by PissedOffCil View Post
    ...
    8- Put the wheel back in and got the proper lever throw

    The brakes are perfectly bled, this is not the problem for sure. The lever is firm and consistent. I can hang the bike upside down and pull the lever and it remains firm. I'm 100% positive there is absolutely no air in the system.
    So what's the problem?
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  10. #10
    g3h6o3
    Reputation: PissedOffCil's Avatar
    Join Date
    Oct 2007
    Posts
    3,708
    Quote Originally Posted by zebrahum View Post
    So what's the problem?
    How often do you need to remove your wheel to get the proper lever throw?
    The pistons should self adjust, not force me to remove the wheel as the pads wear out.
    Check out my SportTracks plugins for some training aid software.

  11. #11
    Picture Unrelated
    Reputation: zebrahum's Avatar
    Join Date
    Jun 2005
    Posts
    4,980
    Quote Originally Posted by PissedOffCil View Post
    Hum.. I just got this idea. Maybe it's the free stroke adjustment screw. The reviews I read and the experience I got is that it doesn't change much but maybe it changes how far the piston retracts...
    That's more of a lever feel adjustment if I understand it correctly. It certainly won't hurt to try it though. Maybe you need to open the reach adjuster up all the way and try bleeding again. I guess I could just be misunderstanding the issue because it sounds to me like the system works fine when you have the wheel in place which is what you want.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  12. #12
    Picture Unrelated
    Reputation: zebrahum's Avatar
    Join Date
    Jun 2005
    Posts
    4,980
    Quote Originally Posted by PissedOffCil View Post
    How often do you need to remove your wheel to get the proper lever throw?
    The pistons should self adjust, not force me to remove the wheel as the pads wear out.
    But you keep saying that you get the pistons to pump up properly when you put the wheel in. If there's anything wrong with the wear adjustment that means you need to re-bleed your brake.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

  13. #13
    g3h6o3
    Reputation: PissedOffCil's Avatar
    Join Date
    Oct 2007
    Posts
    3,708
    You're not ****ing reading what I'm writing or what?

    After pushing the pistons in, if I pump the lever with the wheel in place, the pads will contact the rotor and when I release they will retract too far such that it doesn't give me the lever throw I like. I need to remove the wheel in order to push the pistons out of their seat until they are at the position which gives me the lever throw I like. Then I can put the wheel back in place and they work perfectly.

    I don't know how to make this clearer.
    Check out my SportTracks plugins for some training aid software.

  14. #14
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,334
    How many times did you actually pump? Just keep at it and I bet the lever feel will come back.

    Is this still an issue or was it a one time thing and you want to know why it wasn't back the way it was?
    WHY ARE YOU YELLING??!1

  15. #15
    g3h6o3
    Reputation: PissedOffCil's Avatar
    Join Date
    Oct 2007
    Posts
    3,708
    I don't know, 10-15 times maybe. Enough to see it wasn't doing anything anymore... On all other brakes I dealt with, it took 3-4 pumps to get the proper lever feel.

    Can't tell if it's always been this way. I never really paid attention to it and I'm not sure if I pushed the pads in before. I can't tell, sorry.
    Check out my SportTracks plugins for some training aid software.

  16. #16
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,334
    So is it fixed now?

    You pushed the pistons in too far. The correct amount is actually when they're touching the orange caliper bleed block that came with the brakes.
    WHY ARE YOU YELLING??!1

  17. #17
    g3h6o3
    Reputation: PissedOffCil's Avatar
    Join Date
    Oct 2007
    Posts
    3,708
    The brakes work perfectly, I'm curious about this behavior as I don't really like the thought of having to remove my wheel as my pads wear out...

    Never heard of pushing the pistons in too far before... Fine for the orange block, but with or without pads? I'm guessing with...
    Check out my SportTracks plugins for some training aid software.

  18. #18
    I <3 dirt
    Reputation: Ilikemtb999's Avatar
    Join Date
    Oct 2010
    Posts
    1,334
    Yea with.


    My XT's did a similar thing when I was cutting the lines. I did it without bleeding and pumped the pistons out farther then normal to do it. Then pushed them back fully in and they wouldn't come back out and the lever was on the grip. I pulled the wheel and popped in the spacer and then pumped away. Sure enough they came back to where they needed to be.

    They should move their way out as they wear...I wouldn't be worried.
    WHY ARE YOU YELLING??!1

  19. #19
    g3h6o3
    Reputation: PissedOffCil's Avatar
    Join Date
    Oct 2007
    Posts
    3,708
    Oh well, that's funny. I'm still wondering if the free stroke adjustment has something to do with it...
    Check out my SportTracks plugins for some training aid software.

  20. #20
    mtbr member
    Reputation:
    Join Date
    Jul 2008
    Posts
    661
    Sometimes it just takes a lot of pumping.

    (cue "That's what she said" jokes).

  21. #21
    Picture Unrelated
    Reputation: zebrahum's Avatar
    Join Date
    Jun 2005
    Posts
    4,980
    Quote Originally Posted by PissedOffCil View Post
    You're not ****ing reading what I'm writing or what?

    After pushing the pistons in, if I pump the lever with the wheel in place, the pads will contact the rotor and when I release they will retract too far such that it doesn't give me the lever throw I like. I need to remove the wheel in order to push the pistons out of their seat until they are at the position which gives me the lever throw I like. Then I can put the wheel back in place and they work perfectly.

    I don't know how to make this clearer.
    So your lever doesn't feel the way you like? Play with the adjustments. It's not related to pressing the calipers.
    Don't you hate it when a sentence doesn't end the way you think it octopus?

Similar Threads

  1. How to bleed Shimano XTR M985 brakes
    By jhymel in forum Brake Time
    Replies: 45
    Last Post: 12-18-2013, 02:24 PM
  2. Shimano Xtr m985 vs m988 differences?
    By gsxrawd in forum Brake Time
    Replies: 33
    Last Post: 09-11-2013, 09:28 PM
  3. Shimano XTR M985 vs Time X Roc S
    By Coop1969 in forum General Discussion
    Replies: 16
    Last Post: 04-16-2012, 04:26 PM
  4. Shimano BL-M985 compatible with BR-755?
    By jager7 in forum Brake Time
    Replies: 1
    Last Post: 12-27-2010, 02:36 PM
  5. Anyone Try the XTR M985 Shimano Pedals?
    By myitch in forum Drivetrain - shifters, derailleurs, cranks
    Replies: 8
    Last Post: 11-27-2010, 06:17 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •