Avid Brake Pad Change + Rubbing

Discussion in 'The Workshop' started by M.C. Gong, Mar 29, 2011.

  1. M.C. Gong

    M.C. Gong I am the motor

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    Just changed out my Avid Elixir Pads but not the rotor rubs on both sides. I tried to push the pistons back in on both sides as much as they would go. The piston still sticks out inside the caliper about 1-2mm. When I squeeze the lever now, there is no play before it engages...the pads are constantly touching the rotor. Seems like I need to let some fluid out of the system or something. Will bleeding solve this. Thanks
     
  2. thomaswildchild

    thomaswildchild Active Member

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    Don't bleed them, you just need to push the pistons back more. (Same issue to mine when changingpads) put the old ones back in and using a flat blade or standard screwdrivew twist to push both back at the same time. Take the pads out and try the new ones for clearance. If they still rub then clean the area around the pistons, perhaps there is some build up there. You can bleed them but if they worked fine before the youshouldnt have to...
     
  3. M.C. Gong

    M.C. Gong I am the motor

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    Thanks I'll give that I try. I tried to push them out with a wrench and they wouldn't move any further. I'll give it one more try.
     
  4. RustyIron

    RustyIron Rob S.

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    If your system has excessive fluid, no amount of pushing will get the pistons to move in further. If that is the case, you can barely crack the bleed screw and put a rag over it. Then push the pistons in more, and all will be well. Even so, I'm a big proponent of bleeding the brakes frequently, and now would be a good time.
     
  5. thomaswildchild

    thomaswildchild Active Member

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    I agree, but if they worked fine before then why work on it? Also there could be excessive fluid, but if they didnt act like that from the beginning then why would they do so after time?
     
  6. cruzin 52s

    cruzin 52s Member

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    I woud put that wedge in between the pads that came with your brakes.That will bring them out to the correct opening.It never hurts to bleed them then you would know every thing is spot on.
     
  7. sir crashalot

    sir crashalot Member

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    Did you turn the pad contavt adjuster all the way "in" (counterclockwise) before you pushed in the pistons? It puts the brake system at max volume so you can more easily push the pads back in. Try this before you let any fluid out. Also, what works really well to push pistons in is to install old pads you dont care about, wedge in a big flat scredriver and rock back and forth until theyre pushed in. If pads arent in, a plastic yellow Pedro's tire lever seems to work well. And +1 on what Crusin said, the pad spacer puts the pads into a good position, maybe try that first (make sure its clean!) and see if then you get the right gap. I always do that when I put in new pads; first I push pistons all the way in, install the pads, then squeeze levr a bit to push the pads out a tad, then I wedge in the pad spacer (not the bleed block, the other thing) to push the pads back in to the perfect gap. then loosen cps bolts, install wheel w/rotor, turn the pad contact adjuster back "out" about 2/3 of the way, squeeze lever several times , then hold it squeezed while tightening cps bolts.
    Also, have you ever bled, or had someone bleed, it? If it was bled either without the bleed block in (pistons fully in) or without the pad contact adjuster dialed all the way "out" (clockwise) it will be overfilled. Of course, if that was the case, you would have had problems before with them rubbing or tightening up, especially when hot.
     
  8. M.C. Gong

    M.C. Gong I am the motor

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    Thanks all for the responses. I have Avid Elixir brakes, so I don't think I have the pad adjustment. The brakes have never been bled since I bought the bike from The Path about 7-8 months ago.

    Ok I tried it again. Tried to push the pistons all the way out and still rubs...no space in between the pad or rotor. Not sure if the rotor is all the way in, but it sure looks like it. Another thing I found is that only the inside piston moves out. The outside piston seems to be stuck. Maybe that has something to do with it. Do I need to take the caliper apart and rebuild it.

    My bleed kit is coming tomorrow and I'm pretty sure I can tackle that, but not sure about taking apart the caliper to fix it.
     
  9. M.C. Gong

    M.C. Gong I am the motor

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    Just did some google'ing and found that it is common for Elixir R brakes to have sticky pistons and that bleeding will solve the issue. So I'll bleed the brakes tomorrow and see if that helps. Thanks
     
  10. blindman_22

    blindman_22 HAB Crew President

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    the sram youtube vid is pretty straight forward on how to bleed.
     
  11. xhuskr

    xhuskr Powered by Guinness

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    go for a ride and hit the brakes hard a few times to seat them into position. It doesn't always work, but has for me...just 3 weeks ago on my Juicy 7s
     
  12. M.C. Gong

    M.C. Gong I am the motor

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    Thanks, tried this and opened the screw a little bleed out some of the fluid. It worked and both pistons now move...still need to bleed as the brake lever moves in too much now. Guess there was too much fluid or air in the system.
     
  13. Garrett

    Garrett Active Member

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    Another trick, you can fill a syringe with a bit of fluid (1/4 maybe), connect it to the caliper bleed port and push the pistons in. Then insert the bleed block, apply some pressure to the syringe while unthreading it, and replace the bleed screw.

    Worked great on mine when I had the same problem and I didn't need to do a full bleed.

    On another semi-related note with the Elixirs, a tip that was posted on Pinkbike a while back has helped mine a lot. They used to get stuck or slow pistons all the time. The video recommended that you take the pads out and watch the pistons as they push out. Using a flathead screwdriver, hold the faster piston from moving, which forces the other piston to move faster. This somehow "trains" the pistons to move at the same speed. Not sure how it works, but it seems to make a major difference with the feel of my brakes.
     
  14. jae2460

    jae2460 Active Member

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    Is this the first time you changed the pads since buying the bike? Both of my oem elixir R's wound up being replaced under warranty by SRAM--just got a new rear brake today... There was a similar problem when changing the pads. I'm not mechanically inclined, so when I couldn't easily get the replacement pads in, I took it back to The Path and they found the problem--first with the front, and most recently with the rear.
     
  15. bing!

    bing! Active Member

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    this advice is golden.

    i actually bled the brakes before i found this. i blasted the pistons with brake cleaner and pushed them back as above.

    sticky pistons suck.
     
  16. boyfester

    boyfester New Member

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    Do both Elixir calipers' pistons move or only one side? It sounds like I may need to blast both of my pistons out with brake cleaner as I'm hearing intermittent squealing when the brakes are NOT applied. I think I may have sticky pistons. I replaced the pads and bled the brakes last night but still hear the squealing. I noticed only one of the pistons (wheel side) seemed to move. I'd like to try holding this piston with a screwdriver and see if the other one moves when I actuate the levers.
     
  17. exrcyst

    exrcyst Member

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    I'd say avoid using screwdrivers. If you happen to have something like ceramic pistons, you could damage the piston (I know the Avids are cheapo plastic, but if any Shimano users are reading this, be careful). Try a plastic tire lever or the park tool specifically designed for this type of service.
     
  18. Garrett

    Garrett Active Member

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    Yea, a plastic tire lever is preferred.

    Both pistons should push out the same distance when you squeeze the brake lever.
     
  19. herzalot

    herzalot Well-Known Member

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    He (TWC) did say use the screwdriver with the old pads back in place, so not directly on the pistons.

    "put the old ones back in and using a flat blade or standard screwdrivew twist to push both back at the same time."

    But yes, I agree, avoid screwdrivers directly on pistons.
     
  20. strobe

    strobe resident noob

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    Using a standard screwdriver directly on the pads could cause them to chip/crack/flake. Just pointing out there are ways to cause damage with multiple methods if not done carefully. I usually use a open end wrench on the pistons and apply even/slow pressure. I also have a plastic tire lever when i want to be less careful. I'm sure that will cause damage some day, but, i'm running Juicy's and wouldn't hate a need to upgrade.
     

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