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  1. #1
    mtbr member
    Reputation: Thatshowiroll's Avatar
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    Age-old disc brake question.

    First, I'd like to say that everything I've learned about disc brakes, I got from here.

    I purchased brand new XT brakes/bleed kit and installed/bled them myself. First time I ever do that. They work but, pads rub and the lever is spongy. Rotors are true and I've tried the "loosen the bolts, squeeze the lever and re-tighten bolts" method. That helped a bit but still rubbing.
    What can I do?

  2. #2
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    Some systems are trickier than others due to caliper plumbing. If it's spongy - there's air. If the air expands due to heat, it'll rub.

    I usually push the pistons out before bleeding and push them back right before closing everything up.

  3. #3
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    Quote Originally Posted by vk45de View Post
    Some systems are trickier than others due to caliper plumbing. If it's spongy - there's air. If the air expands due to heat, it'll rub.

    I usually push the pistons out before bleeding and push them back right before closing everything up.
    Not sure what that means. When bleeding, I had the pads out with the 1cm bleed block in. Sounds like the pistons were spread out too wide?

  4. #4
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    New system? Did you add the fluid from the master cylinder or the caliper? When I put on a new Hayes master cylinder with an old caliper this is how I did mine.

    I pushed the pistons in with a box wrench or other means making sure they were flush with the casing. I installed a set of old pads and put a piece of plastic just big enough to squeeze in-between the pads. I hooked up the bottle of good fluid to the master cylinder and the drain hose to the caliper to drain into a red solo cup. i cracked open the caliper bleed screw on the caliper and lightly squeezed the bottle till a good flow of oil come out. Keeping pressure on the bottle I squeezed the brake lever a few time to get he air out. Again, keeping pressure on the bottle I closed the caliper bleed screw and added more fluid to the bottle. I then reopened the system and squeezed more oil through just to make sure I got all the air out then I close the bleed screw. I cleaned up with isopropyl alcohol. To center the caliper on the rotor I did the loosen the mounting bolts and pull the lever a few times. While holding the lever I lightly tightened the mounting bolts AND eyeballed for fine tuning the centering..... sorry for the the long description, hopefully what ever it is I wrote makes sense. always refer to the manufactures recommended bleed procedures
    '11 Jedi
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  5. #5
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    Thanks shwinn8. I'm going to try your method.

    BTW I see you're a Schwinn fan. I just retired my "2001 Moab 1" after 12 years of great service. What a sweet bike.

  6. #6
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    rock on! to add to my collection a moab is on the list.. but not right now
    '11 Jedi
    '01 Straight8
    '01Rocket88< ran over it.. always do a full walk around!
    '00 Homegrown

  7. #7
    @trailgrinder
    Reputation: Live2rideUtah's Avatar
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    You can try by burping your resovoir also, great info for you on how to center the rotors. I bled mine and just opened the top and it let a little air out then worked great.

  8. #8
    San Miguel Beer Drinker
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    i always align my calipers by sight.

    just make sure that you have the lighting conditions right

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