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Brake bleeding

sparky.2002sparky.2002 Posts: 118
edited April 2012 in MTB workshop & tech
Quite a few on here seem obsessed with bleeding brakes. As the lever, hose, caliper is a sealed system. If there was any way for air to get in, then surely you would also have evidence of fluid loss?? Or am I missing something??

Posts

  • nicklousenicklouse Posts: 50,675 Lives Here
    they are missguided. without damage there is no way.

    if there is already air in there then that is another story.

    Bleeding is the last thing that should be done as most issues are set up or users in a hurry.

    or just people that have not read the manual and gone blindly in.

    also the retailers not providing the pad spacers is another issue.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • cooldadcooldad Posts: 32,599
    Hallelujah. This thread should be made a sticky.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • benpinnickbenpinnick Posts: 4,148
    If you have Avids, bleeding does become a bit of an obsession. For whatever reason, they just need bleeding regularly.
    A Flock of Birds
    + some other bikes.
  • nicklousenicklouse Posts: 50,675 Lives Here
    benpinnick wrote:
    If you have Avids, bleeding does become a bit of an obsession. For whatever reason, they just need bleeding regularly.
    none that i have fitted did.(other than for shortening hoses).

    and I have fitted more than most on here.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • sparky.2002sparky.2002 Posts: 118
    edited April 2012
    even if there not leaking??
  • benpinnickbenpinnick Posts: 4,148
    every pair I or my friends have owned end up pulling to the bar at some point with no real reason why. Can't explain it, its just what I have seen happen.
    A Flock of Birds
    + some other bikes.
  • bennett_346bennett_346 Posts: 5,029
    benpinnick wrote:
    If you have Avids, bleeding does become a bit of an obsession. For whatever reason, they just need bleeding regularly.
    I've had 3 different sets of Avid brakes in the last 2 years and none have needed bleeding nor had any other problems. People i know have had other avid brakes and also never needed bled.
  • ricardo_smoothricardo_smooth Posts: 1,281
    many people mistake the fact that their pads are wearing out for them thinking that the brakes need bleeding
  • many people mistake the fact that their pads are wearing out for them thinking that the brakes need bleeding

    the wear of the pads shouldn't make any difference as the master cylinder will take fluid from the reservoir to compensate for pad wear.

    i have never touched the shimano brakes on my 07 trek ex7, the avids on my 6 month old remedy have been done once. front lever coming back to the bars on the furthest reach setting.
  • ricardo_smoothricardo_smooth Posts: 1,281
    I found when I ran avids, you could tell from the lever travel when the pads were low (no contact adjustment etc). I run shimano's on both my bikes now and find them spot on and consistent no matter what the pad levels. I was specifically talking about Avids (few friends have had/still have them). Could be an internal seals issue if its happening already, doesn't mean they are leaking anything but can still fail
  • gloomyandygloomyandy Posts: 520
    So the spaces are a bit of a mystery to me. How exactly are you supposed to use them? Also I'm a little puzzled about comments I keep seeing about pumping the leavers a couple of times to set the self adjust point? How does that work? How is this different from when you use the brakes in normal use? I'm totally new to disc brakes of any kind and would love to understand how this all works and I would certainly like to avoid having to bleed by Elixir 3 brakes if I possibly can! Oh and on that topic I assume there is no way to adjust the contact point with these brakes (don't think there is any adjuster other than reach on the leavers)...

    Thanks for any help..
  • nicklousenicklouse Posts: 50,675 Lives Here
    gloomyandy wrote:
    So the spaces are a bit of a mystery to me. How exactly are you supposed to use them? Also I'm a little puzzled about comments I keep seeing about pumping the leavers a couple of times to set the self adjust point? How does that work? How is this different from when you use the brakes in normal use? I'm totally new to disc brakes of any kind and would love to understand how this all works and I would certainly like to avoid having to bleed by Elixir 3 brakes if I possibly can! Oh and on that topic I assume there is no way to adjust the contact point with these brakes (don't think there is any adjuster other than reach on the leavers)...

    Thanks for any help..
    there are no spacers.

    there is the CPS system (which should be regarded as part of the caliper). contact point no but as you use them the pistons will settle and the movment will become less.

    I suggest reading the manual.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • gloomyandygloomyandy Posts: 520
    I have read the manual and it refers to a setup spacer that is used to set the spacing of the pads/pistons and that can also be used to keep the pads apart if the wheel is removed. Another poster also referred to these earlier in the thread. The thing is my bike came without the spacers (it was a showroom model). Looking at the Avid bleed kits it seems that these contain the spacers but my understanding is that normally they are supplied with a new bike...

    EDIT: Seems that the manual refers to this spacer as a "bleed block"...
  • cooldadcooldad Posts: 32,599
    It basically just takes up the space the disc would when the wheel is off the bike. Stops the caliper closing if you brake without the wheel on.
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • The RookieThe Rookie Posts: 27,804
    many people mistake the fact that their pads are wearing out for them thinking that the brakes need bleeding

    the wear of the pads shouldn't make any difference as the master cylinder will take fluid from the reservoir to compensate for pad wear.
    On the Avids it doesn't always do this very well, the pads retract to far off the disc and then the lever travel is all used up by the time you get any braking, people 'correct' this by overfilling (and calling it bleeding as they don't remove the pads and wedge the pistons back while doing it) rather than by other methods (tweak the lever reach adjust and elastic band lever to bars for a while works well).
    Current steed - Whyte T129, 2013 frame, mongrel Revelations, Giant dropper, Stans S1 wheelset. 12, Magura Trail Sport brakes, 1x11. 12.8Kg
  • benpinnickbenpinnick Posts: 4,148
    How would adjusting the lever reach possibly solve the problem? Especially if the reach was all the way out already like 99% of levers are (as most people never change the reach from the factory).
    A Flock of Birds
    + some other bikes.
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