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  1. #1
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    Front Shimano SLX brake power loss

    I have 203/180 Shimano SLX brakes on my bike, the rear works fine and locks up with a good squeeze of the lever. The front not so much. The brakes are new, this would be their third ride and trying the front lever, it pulls and feels as firm as the rear but it's not stopping at all, even with the 203 rotor.

    I had the bike upside down before this ride, could this be the reason? Air bubbles? Contaminated pad?

    Any remedies before I try my LBS? Thanks!

  2. #2
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    Did you set them right when you installed them?

  3. #3
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    Did you try cleaning rotor and pads with rubbing alcohol?

  4. #4
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    Quote Originally Posted by pfox90
    Did you set them right when you installed them?
    What do you mean?

    They worked fine on the first 2 rides lol. Had the bike upside down last night and now this happens today on the trail. It was fun only using the rear brake.

    Also the fronts now make a loud noise whenever you use them.

  5. #5
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    I mean did you loosen your caliper, squeeze the brake like 3-4 times, hold down the brake lever and then tighten your caliper back? If the caliper isn't centered it most likely won't work anyways.

    You may have gotten oil on them

  6. #6
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    Quote Originally Posted by pfox90
    I mean did you loosen your caliper, squeeze the brake like 3-4 times, hold down the brake lever and then tighten your caliper back? If the caliper isn't centered it most likely won't work anyways.

    You may have gotten oil on them
    I didn't installed them. And I didn't touch them or adjust them since they worked fine when I picked up my bike. The thing I could see going wrong is getting air bubbles into the line when the bike was upside down 2 nights ago.

  7. #7
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    If there is a possibility of having gotten air in the line proceed with the bleeding proceedure. If air comes out then that was needed. It might be better to clean the rotor and pads and check alignment first.
    Half our life is spent trying to find something to do with the time we have rushed through life trying to save

  8. #8
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    Sealed system. Air isn't just going to get in them by storing upside down.

    If you have a firm feel, just no stopping, it's either contaminated pads and rotor or it is our of adjustment and needs centered.

    You did go through the bed in process, didn't you?

    Never touch your rotors, skin oil will even contaminate pads and they'll need sanded and cleaned with blake kleen.

  9. #9
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    Quote Originally Posted by ratmonkey
    Sealed system. Air isn't just going to get in them by storing upside down.

    If you have a firm feel, just no stopping, it's either contaminated pads and rotor or it is our of adjustment and needs centered.

    You did go through the bed in process, didn't you?

    Never touch your rotors, skin oil will even contaminate pads and they'll need sanded and cleaned with blake kleen.
    Rotor's perfectly adjusted.

    So, I first cleaned the rotor and took the pads and used rubbing alcohol. No improvement. Next tried some mineral spirits for the heck of it. And still no improvement. Cleaned the rotor one more time with rubbing alcohol and took the pads from the rear and put them in the front. And full braking power was back. Also no more harsh noise if slightly on the brakes.

    I returned the rear pads to the back and will have to stop by REI in the morning to pick up some new Shimano M07S resin pads before my little trip to Rock Cut State Park tomorrow. Thankfully they have some in stock.

    But how does one contaminate a pad within 3 rides? On my last bike, I never experienced anything like it and I wasn't too careful with that bike. And I don't recall touching my rotors on this bike, at least lol.

    Thanks for the help guys!!

  10. #10
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    Mineral spirits leave a residue. don't use it to clean brake rotors.

    Sand the pads with 100 grit and they'll be good as new

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