Results 1 to 15 of 15
  1. #1
    mtbr member
    Reputation: Pezerinno's Avatar
    Join Date
    Sep 2004
    Posts
    125

    disk brakes rubbing?

    Hi, I have recently bought a new bike but my front disk brake is rubbing. The brake in question is a Hope mono M4 200mm hydrualic. It's a continous rub from one side of pads. Everything is new so should not be worn/warped/buckled etc

    I've heard people comment on how disk brakes always rub/drag a little however this is actually making quite a lot of resistance when I try and ride, also the back one doesn't seem to rub at all. You can quite clearly see the disk is too far over one side - could do with going about .75mm to the left to make the disk central.

    I've tried the trick with the playing cards which stops the rubbing nicely until I reapply the brake a couple of times resulting in it going back to normal, in this case - rubbing.

    I'm new to disk brakes so am a little unsure of what adjustments I could try and make (if any) I have tried loosening the caliper and wiggling it more centrally on the disk but once tightened it reverts back to its original position. There's also a screw coming out the top of the caliper with a protective black rubber outing - but am not sure what this does.

    I have taken it down the my lbs but they haven't fixed the problem ( I picked my bike up just before closing time so didn't stop to try it out)

    Anyway any help would be much appreciated. Thanks, Nick.

  2. #2
    Riding a Rig.
    Reputation: Vulcan's Avatar
    Join Date
    May 2004
    Posts
    1,157
    Probably just need to bend the rotor a bit. Check out the
    disc brake faq's.

  3. #3
    UKMac
    Guest

    I would go to http://www.hopetech.com/ for the Manual

    It should be able to explain all of the bits of the brake for you. Unfortunately the Hope manuals are crap for troubleshooting, IMO.

    The "screw" coming out of the top with the rubber cap on it is the bleed nipple I'm pretty sure, so don't turn it unless you're bleeding the brakes (and if you are, be sure to read how to do it in the manual first). Also, I wouldn't loosen and/or reposition the caliper for this problem; the caliper needs to be centered (square) over the rotor for good performance.

    I have two sets of Minis and can say that the seals can be quite tight initially which can cause the pistons to not retract properly (either too much or not enough in your case). I have solved this problem in the past by removing the wheel and pads and moving one piston at a time in and out. To accomplish this you hold the other piston in place with a small screwdriver while moving it by gently squeezing the lever. Don't overdue this or you'll pop the piston right out of the caliper (then you will need to bleed the brakes). Once extended, push the piston back in with the screwdriver taking care to push evenly so the piston doesn't bind on the way back in. Repeat this five or six times on each side. Replace the pads and wheel and squeeze the lever a few times to reposition the pistons.

    For really tight or dry seals, you can apply silicone plumberís lube on the extended pistons when carrying out the procedure I just described. I got all of these tips by calling Hope in the UK, and I've used them successfully myself. If you are unsure of this, or need other advice on the brakes, I wouldn't hesitate to call Hope in the US or UK. Good luck.

  4. #4
    UKMac
    Guest

    And another thing..

    Unless the cause of the problem is a bent rotor, I would definately NOT try to solve this problem by bending the rotor!

  5. #5
    mtbr member
    Reputation: Pezerinno's Avatar
    Join Date
    Sep 2004
    Posts
    125
    thanks for the reply UKMac. Will have ago tomorrow. Are the pads easy to get off?

  6. #6
    UKMac
    Guest

    I think so

    If they're like the mono's all you have to do is remove the cotter pin and the retaining pin and pull the pads out. Have a look and I think you'll know what I mean. Be careful not to touch the braking surface of the pads (or the rotor for that matter) because even the oil from your skin can affect the performance of disc brakes.

    Also, after re-reading your first post it sounds like you may have a Manitou fork (I get this from the wiggling the caliper comment, wiht IS you'd have to remove shims). If this is true getting the caliper centered is a bit more difficult than with IS; I would recommend making sure it's properly centered by putting the wheel back after removing the pads (IMO pads are a distraction when centering the caliper). I have both a Fox (IS) and Manitou (Hayes) and find it harder to center the caliper with the Hayes mount, but both work fine.

  7. #7
    Authority is dead!
    Reputation: Lucky13's Avatar
    Join Date
    Jan 2004
    Posts
    1,812

    doh

    adjust caliper position with washers.
    [SIZE=5]For the love of Oi[/size]

    [size=6]Rent a house at Attitash[/size]

  8. #8
    UKMac
    Guest

    Not with a Hayes Mount

    Quote Originally Posted by Lucky13
    adjust caliper position with washers.
    IS uses shims or "washers", but with hayes you simply move the caliper back and fourth--No shims. Manitou forks use hayes mounts.

  9. #9
    mtbr member
    Reputation: Pezerinno's Avatar
    Join Date
    Sep 2004
    Posts
    125
    I actually am using a 2004 marzocchi Z1 freeride QR20 on this bike. Are they similar to manitou forks?

  10. #10
    mtbr member
    Reputation:
    Join Date
    Jan 2004
    Posts
    57
    I have the same set up on my bike, you have to adjust the position of the brake caliper with some washers.

  11. #11
    UKMac
    Guest

    No it's IS, but the basic advice stays the same

    center the caliper using the shims (washers), don't reposition the caliper to compensate for a rubbing piston. Instead use the procedure I described in my first post.

  12. #12
    83 feet less per minute
    Reputation:
    Join Date
    Jun 2004
    Posts
    732
    Try loosening both attachment bolts slightly, spin wheel to center caliper, then carefully re-tighten bolts. I have to do this when changing wheels, since all wheels have some slight variation in distance of rotor from center. Can't hurt to try. Make sure axel is all the way into drop-outs first.

  13. #13
    mtbr member
    Reputation: yknotryde's Avatar
    Join Date
    May 2004
    Posts
    21

    Got the same problem with my "new" XT discs

    And I stopped by this forum seeking answers. My problem is with the rear and I too don't know what to do. It doesn't rub alot but it is a big difference compared with the free rotation after I push the pads apart. Is there a way to adjust the distance the pads recess after each lever pull?

  14. #14
    Authority is dead!
    Reputation: Lucky13's Avatar
    Join Date
    Jan 2004
    Posts
    1,812

    doh

    Bleed with pads touching the rotor, USE WASHERS to adjust position of the caliper.
    [SIZE=5]For the love of Oi[/size]

    [size=6]Rent a house at Attitash[/size]

  15. #15
    mtbr member
    Reputation: yknotryde's Avatar
    Join Date
    May 2004
    Posts
    21

    Thank You Lucky!

    Because I couldn't read your first reply of "doh" which was so friggin' helpful. "Use washers" That is clear as day, now we know what to do, thanks. But thank you really because your lack of help reminded me that if you really want something done you have to do it yourself.

    So for anyone else here that needs some assistance with their brakes check out this website

    http://www.utahmountainbiking.com/fix/

    Adjusting the mounting screws did the trick for me and my wheels are running SO smoothly now.

Similar Threads

  1. Disk brakes, or a new fork...
    By summitlt in forum General Discussion
    Replies: 5
    Last Post: 08-31-2004, 03:12 PM
  2. Which disk brakes do I want (for racing)?
    By CKS in forum Weight Weenies
    Replies: 58
    Last Post: 06-03-2004, 09:07 PM
  3. modify frame 4 disk brakes?
    By jman0war in forum General Discussion
    Replies: 3
    Last Post: 03-28-2004, 05:05 PM
  4. Ahoy! V-brake holdouts!
    By Padre in forum Singlespeed
    Replies: 29
    Last Post: 03-23-2004, 09:06 AM
  5. Replies: 7
    Last Post: 03-01-2004, 05:45 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •