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  1. #1
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    New question here. Weird front braking piston. Help.

    Hi everyone, I have a Rock Hopper 2012 with Tektro Draco hydraulic disc brake, post mount, 160mm 6-bolt rotor.

    Recently, I notice that my front brake has constant friction with the rotor. The piston on the right is pushing out even though I am not pulling the lever. However, the left piston is working properly. Here is a picture. I tried to recalibrate the brake position and push the piston back in position. But it doesn't seem to work.
    Weird front braking piston. Help.-2013-10-24-11.17.21.jpg

    As you can see, the right piston is pushed out (with no force on the brake lever). Now I am considering bleeding the front brake. But I am not sure if this will solve the problem.

    Can anyone give some advice with my issue? Any response is appreciated.

  2. #2
    EDR
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    Re: Weird front braking piston. Help.

    Try cleaning and lubing the piston's. Likely a sticky seal.

  3. #3
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    "I tried to recalibrate the brake position and push the piston back in position"

    Describe what you did here.
    Did you reset both pistons in the caliper so that both were flush and fully retracted?

  4. #4
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    Quote Originally Posted by Norman Clydesdale View Post
    "I tried to recalibrate the brake position and push the piston back in position"

    Describe what you did here.
    Did you reset both pistons in the caliper so that both were flush and fully retracted?
    Since only the right piston is pushed out, I tried to push it back into position with a screw driver. However, it stuck and won't go back in. The left piston is fully retracted. So they are not flush.

    Hope I described clearly.

  5. #5
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    Not sure exactly how you went about the process, but try the following if it is different than the way you went about it.

    -Leave brake caliper on bike
    -Remove brake pads
    -Use a plastic tire lever or something non metal to push/pry the piston back to flush. You can damage the pistons with a screwdriver. It may take some force.
    -You should be able to get even a sticky piston to move at this point
    -If not, rinse and clean the pistons in the calipers with iso alcohol and give the brake lever a slight squeeze. Not enough to push the pistons all the way out, but just enough to see a bit of movement.
    -Clean the pistons with iso alcohol again
    -repeat the the piston reset exercise with a plastic tire lever. You should now be able to get both pistons fully flush with the caliper body.
    -if it works, replace pads, align caliper and go ride.
    -if it doesn't work, I'd then start looking for the problem at the brake lever cylinder.

  6. #6
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    Thanks, I will definitely try this.

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