Deore V Brakes sticking

Discussion in 'Cycling Equipment' started by missionaryman, May 2, 2006.

  1. missionaryman

    missionaryman New Member

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    I bought a 2004 Specialized Sirrus Comp from a friend and he had upgraded the standard brakes to Shimano Deore units because the original ones would keep leaning to one side and rubbing after applying them, now the Deore ones are doing it too - can I beef up the return spring or something to make them stay open when not applied and is there a way to keep them better centred?
     
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  2. Urbanbike

    Urbanbike New Member

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    Hi Missionaryman,
    If this goes without saying, then just ignore it, but have you adjusted the centering using the spring tension adjustment screws on each side? Tighten to pull the brake towards that side, loosen to allow the brake to fall back towards the rim.
     
  3. missionaryman

    missionaryman New Member

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    yeah I tried that and it helps some but they still feel a bit slack and can tend to lean to one side and rub sometimes.

    the tension on the leveres is very light - they could easily handle a much tighter return spring which would fix the problem, can this be done?
     
  4. fish156

    fish156 New Member

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    V brakes would appear to be straightforward, but adjusting them is not. If one boss or the other is a bit sticky this will affect performance. Remove the caliper arms, clean and lube the bosses. Make sure they are perfectly smooth (no burrs!) while you have the arms off. Blue Loctite 242 on the holding bolts when you re-install the arms. Spring tension on both sides must be very close for the adjustment screws to work correctly. Sometimes you have to bend one a bit to strengthen it (compared to it's mate). The adjustment screws should always be adjusted both sides at the same time - loosen one side and tighten the other. If things seem all out of whack, set both screws at a middle position (blue loctite on these guys, too). The side of the brake that moves the most when squeezing the hand control should be loosenned (turn adj screw out) and the other side should be tightenned (turn screw in). Loosenning the adjustment screw reduces spring tension on that side and if one arm is moving more than the other, it has too much spring tension and the way you fix that is by reducing it (turn screw out) - and then go to the other side and increase spring tension by turning the adj screw in (the same amount as you turned the other one out). If your bosses are lubed and the springs are close to the same tension, you will know when you make the correct adjustments because you will see both the left and right arm move (at the same time) to the needed side. Sometimes it will take several sets of adjustments to get both arms to move at once. Once you see them both move at once, you are very close to the correct adjustments. If you get an over correction, go back the other way and use smaller adjustments. It's correct when both arms are at the same angle away from the fork (or seat stays) and they both move the same amount to make the pads contact the rim.

    BTW, Sirrus Comp is pretty nice. I build a lot of bikes and that is one of the nicer models in the middle price range (around $800-1200). I like them a lot, but I would probably upgrade components myself. It's a good base model to buy and then do upgrades.
     
  5. fish156

    fish156 New Member

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    If the overall tension in your brakes seems too light, you can usually fix this problem by removing the caliper arms. At the base of the bosses you should see a little bracket with three tiny holes that one end of the return spring inserts into. Most bikes are set up with the spring end installed in the middle hole. You can stiffen up your brakes by moving the spring end to the next hole (it should be obvious which hole will make the spring wind up more). This will translate back to the hand controls.
     
  6. fish156

    fish156 New Member

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    I would also recommend checking out the Park Tool Repair blurb on V brakes:

    http://www.parktool.com/repair/readhowto.asp?id=21

    Unfortunately, they don't have any discussion at all about how to adjust for centering and tension. I had to learn the hard way, and it took LOTS of practice to get good at it.

    If anyone knows of any good articles on adjusting linear ("V") brakes, please post.
     
  7. missionaryman

    missionaryman New Member

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    Fish - thank you very much for taking the time to give me such a detailed explanation. I will first try the tension setting on the springs by re positioning the hole.

    the Sirrus Comp is normally $1800 (AUS) here + $60 for the pedals and another $80 for the upgraded brakes. I bought it from a colleague for $1000.

    What upgrades would you make to it, I had to get a 45 degree 50mm stem and cannondale riser bars to lift the handlebar height because of a bulging disc in my lower spine.

    I also built this light for it:

    [​IMG]

    1150 Lumens for 1/2hr on High Beam 700 for 80min on Low:
    [​IMG]
     
  8. gclark8

    gclark8 New Member

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    MM are you in the gosnells (WA) area?? :confused: If so, the boys at Jet Cycles can show you how to balance the brakes. I see a wire wound around the front brake cable, that will cause problems in allowing the caliper to return freely.
     
  9. missionaryman

    missionaryman New Member

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    hi guys, thanks for the help. I followed the directions given by both of you and got them to balance well - the cable for the computer was actually too tightly wound near the bottom and stopping the front brake from springing back a little (when I first read that suggestion I thought you must be a rookie - you were dead right!!)

    I got a scare in doing so because when I put the front calipers back on I didn't get the right side located properly and the it felt like the screw was threaded as a result - because it had blue loctite all the way up the thread I thought the bike shop did it and blasted them, then I realised it was just my stoopidity.

    I was told that if this screw got threaded I would need new forks beacuse they are carbon and the housing for the brakes is not serviceable but I think they are wrong.

    This is the mounting screw that I thought I had stripped:
    [​IMG]

    And here is the threaded shaft it screws into that goes into the carbon fork:
    [​IMG]

    You can see that it's shaped to be able to be driven with a spanner so I think it screws into another thread seated in the fork itself. Would this be the case?
     
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