Brake Bleed/Bite point

scarbs85
scarbs85 Posts: 170
edited December 2012 in MTB workshop & tech
I've just bled my rear brake (Avid Elixir 5's) as it was pulling to the bar. Even when its been bled, the bite point is pretty close to the bar, especially now I have brought the reach in a little. Elixir 5's have no bite adjuster and so it got me wondering if you can adjust the bite point by pumping a little extra fluid into the system, or would it just run back out the minute you remove the syringe as it would be slightly under pressure.

The other possibility is I just haven't bled the brake very well, and there is still a little air in there. It doesn't feel spongy, but I have always found the longer hose of a back brake seems to have a little more squidge than the front brake.

Comments

  • Newfish
    Newfish Posts: 121
    Worn pads?
    Cheers,
    Simon.
    ____________________
    2012 Spesh Rockhopper
  • scarbs85
    scarbs85 Posts: 170
    Sorry should have said new pads have gone in. Old pads were well worn and initially I thought that was the problem.
  • The Rookie
    The Rookie Posts: 27,812
    Pads settled on disc or are they still having to close in first?
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • supersonic
    supersonic Posts: 82,708
    Google 'advancing avid pads'.
  • bennett_346
    bennett_346 Posts: 5,029
    It's called the deadband. Always a problem with elixirs from personal experience. I usually bleed in a bit of extra fluid but its really hard to change the pads like this.
  • supersonic
    supersonic Posts: 82,708
    Extra fluid is a bad idea as will not allow the to expand when heats up, and due to the nature of the open system, actually does nothing unless overfilled to excess.
  • bennett_346
    bennett_346 Posts: 5,029
    True but i've never had it heat up enough to cause an issue, and it's been successful as a workaround to a degree.
  • scarbs85
    scarbs85 Posts: 170
    Well I cable tied the brake lever over night to try and advance the pads. It seems like its made a little bit of a difference. I think I will have a ride on it before mucking about with much else. I'm hoping that out on the trail, the fluid should heat up a bit and reduce the deadband (you learn something new every day!).

    Thanks for the advice chaps.
  • I've recently had this problem on my Elixir 3's with the rear brake.

    Did you adjust the reach to where you want it before you did the bleed? If not then this needs doing first.

    I just made sure that when I was doing the lever end part of the procedure that I gave it plenty of goes at vacuum pressure then plenty of squeezes on the syringe to make sure I got that fluid in. I did it with the wheels on as well, no problems.

    The 'advancing pads' procedure didn't appear to make any difference for me. When I bled there was plenty air bubbles coming out and as the bike is quite new it was probably underfilled as was suggested here when I asked for advice.
  • bennett_346
    bennett_346 Posts: 5,029
    The 'advancing pads' procedure didn't appear to make any difference for me. When I bled there was plenty air bubbles coming out and as the bike is quite new it was probably underfilled as was suggested here when I asked for advice.
    Nail on the head there, the advancing pads method has never worked for me, as elixirs are simply underfilled from the factory.
  • supersonic
    supersonic Posts: 82,708
    Well I cable tied the brake lever over night to try and advance the pads

    That is not how you advance the pads. The procedure is near the bottom if this page:

    https://docs.google.com/viewer?a=v&q=ca ... w4_bN4-N6Q
  • scarbs85 wrote:
    I'm hoping that out on the trail, the fluid should heat up a bit and reduce the deadband (you learn something new every day!).

    It won't.

    Incidentally, temperature related expansion or contraction is precisely the characteristic you least want in brake fluid...