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  1. #1
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    Shimano 525 front brake no power

    i got a 2004 scalpel about 2 weeks ago and it came with shimano 525 disc brakes. from the first ride the rear brake has worked great but the front has very little power. the lever pull and feel is the same as the rear, but it is barely is working. i have put about 100 miles on it and have been trying to use the front brake alot to see if it just needed some braking in... any suggestions??

  2. #2
    (aka SS_MB-7)
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    Quote Originally Posted by MI Endo
    i got a 2004 scalpel about 2 weeks ago and it came with shimano 525 disc brakes. from the first ride the rear brake has worked great but the front has very little power. the lever pull and feel is the same as the rear, but it is barely is working. i have put about 100 miles on it and have been trying to use the front brake alot to see if it just needed some braking in... any suggestions??
    So, the front lever feels the same as the rear (approx same engagement point and no spongyness)? If so, then it sounds like the front is properly bled.

    I'd check the rotor and/or pads for possible signs of contamination (oil, fluid, etc.)....it doesn't take much brake fluid, oil, etc. to ruin a set of new pads. Make sure you thoroughly clean the rotor with a clean wrag and some rubbing alcohol. If the pads are contaminated, you can either buy a new set or you can try to salvage them by baking them in the oven at 400-425 for about 20-25 minutes....this will remove the oil from the pads. Before going on a serious ride, please make sure you check your pads and rotor again. I've successfully used the baking technique on several different pads (Hope, Formula, Shimano, etc.) without any issues. Your results may vary though, so be careful.
    Ride Hard,
    Mike B. (MCM# 7.77)
    http://www.one-speed.com

  3. #3
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    the front brake also squeeks very bad. is that a sign of pad contamination?

  4. #4
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    Quote Originally Posted by MI Endo
    the front brake also squeeks very bad. is that a sign of pad contamination?
    Not necessarily. Squeaking, squealing, howling, etc. are possible signs of pad contamination, but can also be signs that the caliper is not properly aligned with the rotor. If you haven't done so already, check this.

    Or, in some circumstances, just the natural frequency of the "system" (wheel, brake, fork, etc.) can cause the system to vibrate/howl. I had this issue on an older frame even though the caliper was perfectly aligned. By adding a few nylon washer to separate the caliper from the frame's tabs, it changed the natural frequency of the "system" and stopped the vibration.
    Ride Hard,
    Mike B. (MCM# 7.77)
    http://www.one-speed.com

  5. #5
    ballbuster
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    Sounds like it to me

    Quote Originally Posted by MI Endo
    the front brake also squeeks very bad. is that a sign of pad contamination?
    I would follow the decontamination procedures (sand off a bit of pad, then soak in alcohol, clean rag and alcohol/brake cleener the rotor) then use some 80-100 grit clean sandpaper to score the brake track on the disk a bit, then clean with alcohol/brake cleener. Your brakes will suck for about 200 feet worth of hard stops, but then the power should come in.

    While you're at it, check the caliper for leaks.

    High pitch squeek is normal for disc brakes, but lower frequency howl is usually a sign of contamination.

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