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  1. #1
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    Hydraulic brake problem

    I'm pretty new to hydraulic brakes, this is the first set i've had and i have only had them for about an month maybe a little more now. I'm having a little issue with my front brake, I have Shimano M486 hydraulic disc brakes and my front brake lever has slowly become a smaller and smaller pull, now the pads rub the whole rotation of the wheel and my brakes lock the wheel up if i just ever so slightly touch the lever.

    This started to happen about 5 days back when me and a friend were loading our bikes in his car to go ride some trails. We have to disconnect our front wheels to fit the bikes in his car and while he was walking my bike (without the front wheel) to the back of the car he pulled the front brake lever all the way closed (he has never used hydraulic brakes only mechanical discs and didn't think anything about what that could do to mine) anyways when we got to the trail I could not fit my font wheel back on the bike because the brake pads didn't have enough of a gap for the rotor. After a little tinkering with the caliper some of the mineral oil leaked out of the line when we loosened one of the screws and then quickly tightened it back up when I noticed that happened. After that you had to pull the lever all the way to the handlebar to get just to get a very minimal amount of braking power but would not lock the wheel up just slow it down a little. We adjusted the lever all the way out so I could get a little braking power out of it so we could ride the trail then go home and try fixing it. After we finished riding I noticed I was able to lock the front wheel up when before i couldn't, then 2 days later i noticed that the pull was getting smaller and smaller, eventually it was back to how i had it set before this whole situation happened, and now my pads are constantly rubbing and if i just tap the lever it locks the wheel up .

    Does anyone have a ideas at how to fix this? would it be something that bleeding the brakes would help? or should i just take it to a shop and pay them to fix it?

    Thanks
    Jared
    Last edited by jaredr68; 05-22-2010 at 10:08 AM.

  2. #2
    AZ
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    Push the pads back as far as you can , remount the wheel and gently apply the brake . You may have to repeat this . You may also remove the pads and push the pistons back as far as you can , remount the wheel and gently apply the brake .

  3. #3
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    Thanks AZ.MTNS that seemed to do the trick, took a little while to get it just right but for now seems to have worked, hopefully it stays that way. Thanks again

  4. #4
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    Same thing happened to me and i learned the hard way not to loosen the bolts holding the caliper together. I ended up contaminating the pads and rotor with mineral oil. Now I have squeaky and unresponsive front brakes.
    After bleeding and refilling the system with mineral oil, i cleaned the pads and rotors with isopropyl alcohol but still squeals. I know I need to replace the pads but will i need to replace the rotor too?
    2009 Kona Kahuna 29er
    2010 Dawes Deadeye

  5. #5
    AZ
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    Quote Originally Posted by harryb714
    Same thing happened to me and i learned the hard way not to loosen the bolts holding the caliper together. I ended up contaminating the pads and rotor with mineral oil. Now I have squeaky and unresponsive front brakes.
    After bleeding and refilling the system with mineral oil, i cleaned the pads and rotors with isopropyl alcohol but still squeals. I know I need to replace the pads but will i need to replace the rotor too?


    Heat the pads to about 375 until they quit smoking . After they cool sand them and clean the pads and rotor with Isopropyl Alcohol .

  6. #6
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    I've tried some similar methods with the pads, but the squealing comes back after 2-3 times using the brake. I think at this point I'll just live with the squealing and use it as a way to warn hikers that I am approaching. I'll grab some new pads next time I'm at the lbs.

    This whole experience is making me consider switching to some bb7's if i have anymore issues with these entry level hydros.
    2009 Kona Kahuna 29er
    2010 Dawes Deadeye

  7. #7
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    Quote Originally Posted by harryb714
    I've tried some similar methods with the pads, but the squealing comes back after 2-3 times using the brake. I think at this point I'll just live with the squealing and use it as a way to warn hikers that I am approaching. I'll grab some new pads next time I'm at the lbs.

    This whole experience is making me consider switching to some bb7's if i have anymore issues with these entry level hydros.
    So what did you do to clean the rotor? Altho could be the pads have just too much contamination and need replacement. Would be harder to contaminate the BB7s, though.

    Jared, next time you need to transport your bike with the wheel off either jam the spacer in between the pads that came with your brakes (or should have) or a shim of some sort (cardboard can work great).
    "...the people get the government they deserve..."
    suum quique

  8. #8
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    Yeah I knew it wasn't good for the brakes for the lever to be pulled when the wheel was out, I've always tried to make sure i didn't accidentally pull the lever or that nothing was going to push on the lever while transporting the bikes. I have done this a number of times when we are heading out to trails and it always worked out fine but I don't think my friend thought anything of it when he was walking it to the back of the car, definitely going to start putting something in between the pads just in case so it doesn't happen again

  9. #9
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    A credit card folded in half works great.

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