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Thread: brake question

  1. #1
    I like bacon... (clyde)
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    brake question

    I finally (luckily) received a Reba Team in place of my Tora 302 fork on a warranty issue. I swapped the forks today and I am having an issue with my front brake caliper. To get the right orientation, I had to get rid of the little adapter that my old fork had to use. The pads engage the rotor correctly, but the adjustment slots aren't wide enough for the inside pad to clear the rotor. It works for braking, but I literally cannot adjust in such a way that it doesn't rub. My brakes are low end shimano hydros, which work decently but always were a pain to keep aligned correctly to the rotor.

    The options I've come up with are: modify the caliper's slots, buy a new (different, more adjustable) hydraulic shimano caliper on ebay, replace the whole front brake system, or buy a whole new set of brakes (front and back). What are your recommendations? Would it be strange to have different brakes on the front and back?
    Bike: '08 Trek 6500
    Color: Oreo
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  2. #2
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    It really seems like you should be able to get this to work with your current parts. Talk to the boys at your LBS and get some rotor shims to bump it out enough to avoid rub.

  3. #3
    I like bacon... (clyde)
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    Quote Originally Posted by CheeseSoda
    It really seems like you should be able to get this to work with your current parts. Talk to the boys at your LBS and get some rotor shims to bump it out enough to avoid rub.
    Awesome. I didn't even know something like that existed. Thanks!

    Granted, they are centerlock hubs and rotors. All the shim packs I've founds so far online seem like they're for 6-bolt setups. I can probably find some kind spacer or washer at the hardware store that will work, though.
    Bike: '08 Trek 6500
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  4. #4
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    You might want to try a simple fix first:

    1. Put the bike into a workstand or turn it upside down.

    2. Remove the front wheel and check the bolts on the left side of the axle haven't come loose.

    3. Insert a large flat bladed tool (eg a screwdriver) between the pads and prize them apart until they sit flush on either side of the caliper slit.

    4. Loosen the mounting bolts holding the caliper onto the fork leg.

    5. Replace the front wheel and make a mental note of how tight you do up the quick release. Each time you remove and replace the wheel, this is how tight it should be put back on.

    6. Gently spin the wheel and watch the rotor to see if it is bent.

    7. Now, center the caliper slit (never the pads) onto the rotor, accommodating any bends in the rotor the best you can.

    8. Slowly screw in the mounting bolts a bit at a time each in turn until they have been fully tighten, but keep watching the spinning rotor.

    9. Put the bike the right way up, raise the front end and spin the front wheel.

    10. Grab the front brake lever and pull gently to reduce the speed of (but not stop) the spinning wheel. Do this two or three times.

    11. Then roll the bike with the wheels on the ground backwards and forwards while pulling the brake lever harder and harder to stop the bike.

    12. The pads will self center (a property of Shimano hydraulic brakes) when you complete this process.

    13. Now take the bike out for a ride to dial-in the pads again. Put the bike into a low gear and pedal hard whilst partially engaging the front brake. The brake should work smoothly after 10mins or so.

  5. #5
    I like bacon... (clyde)
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    ^^^ I'll give that a try before I shim the rotor out. Thanks for typing all that out
    Bike: '08 Trek 6500
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  6. #6
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    Okay but...

    Quote Originally Posted by standard3x
    You might want to try a simple fix first:

    1. Put the bike into a workstand or turn it upside down.

    2. Remove the front wheel and check the bolts on the left side of the axle haven't come loose.

    3. Insert a large flat bladed tool (eg a screwdriver) between the pads and prize them apart until they sit flush on either side of the caliper slit.

    4. Loosen the mounting bolts holding the caliper onto the fork leg.

    5. Replace the front wheel and make a mental note of how tight you do up the quick release. Each time you remove and replace the wheel, this is how tight it should be put back on.

    6. Gently spin the wheel and watch the rotor to see if it is bent.

    7. Now, center the caliper slit (never the pads) onto the rotor, accommodating any bends in the rotor the best you can.

    8. Slowly screw in the mounting bolts a bit at a time each in turn until they have been fully tighten, but keep watching the spinning rotor.

    9. Put the bike the right way up, raise the front end and spin the front wheel.

    10. Grab the front brake lever and pull gently to reduce the speed of (but not stop) the spinning wheel. Do this two or three times.

    11. Then roll the bike with the wheels on the ground backwards and forwards while pulling the brake lever harder and harder to stop the bike.

    12. The pads will self center (a property of Shimano hydraulic brakes) when you complete this process.

    13. Now take the bike out for a ride to dial-in the pads again. Put the bike into a low gear and pedal hard whilst partially engaging the front brake. The brake should work smoothly after 10mins or so.

    Edit to add: The last time I set up hydraulic brakes was about 5 years ago. The proceedure to align calipers may have changed since the last time I set them up. (/Edit)

    Wouldn't it be simplify things to take steps 7+ and do this:

    7. If the rotor is bent in step 6, gently rebend the rotor with a metric crescent wrench to straighten the bend in the rotor.

    8. Spin the wheel again to ensure that the rotor is straight.

    9. Pull the brake rotor (hard) to stop the wheel because the caliper (still loose) will align itself to center on the rotor.

    10. Still holding the brake lever (caliper is still holding the rotor but the caliper is loose), tighten the caliper bolts to their torque spec.

    11. Spin wheel to test that things are aligned.

    12. Ride your bike.


    You could also "upgrade" to a higher end pair of mechanical brakes and likely see a performance increase over lower end hydraulic brakes and eliminate the problem forever.

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