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Brake broken?

glasgowbhoyglasgowbhoy Posts: 1,341
edited September 2010 in Workshop
Took off my brakes to fit my mudguards back on the Defy.
On the back I was trying to adjust them and now it doesn't seem to want to sping back when I release the brake lever. Has the spring gone or has all the fiddling about with the cables just stretched the cable?

Cheers, probably need some bike maintenance training as youtube videos don't seem to be helping......

Posts

  • deswellerdesweller Posts: 5,271
    Might need a little more info than that!

    Does the lever spring back? Does it move through its normal range of travel?
    When you took the brake calliper off, did you undo the cable clamp?

    The steel cables used in bicycle brakes could support your weight quite comfortably, so I wouldn't worry about having stretched it.
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    On Strava.{/url}
  • Remove the brake from the frame & give it a good dose of WD40, then give it some more. Keep squeezing the brake blocks together as you oil it. Eventually it will free off. If, when you remove it, the caliper is free, then new cables should sort it.
    -- "I am but a spoke in the wheel of life" -- Ghandi
  • desweller wrote:
    Might need a little more info than that!

    Does the lever spring back? Does it move through its normal range of travel?
    When you took the brake calliper off, did you undo the cable clamp?

    The steel cables used in bicycle brakes could support your weight quite comfortably, so I wouldn't worry about having stretched it.

    Cheers, no it doesn't spring back just stays locked in the brake on position when I release the brake . Yes I lifted the cable clamp as I removed the wheel to get the mudguard on. The eyelets of the mudguard use the pin through the brake fixing.
  • Was the brake properly centered (after tightening)?

    I had the problem that the brake wasn't centered and it would release but the whole assembly would be offline. i.e. the calipers were rotated and one side was closer (in contact) with the rim.

    If that's the case, then back-off the securing bolt, then using an appropriate (read: thin) spanner hold the nut on the other side (of the seat stays/bridge etc) so that the calipers are in a centered position and tighten the bolt again. The usual problem is that the nut is allowed to rotate while tightening, taking the calipers out of alignment.

    Hope that helps....
  • Was the brake properly centered (after tightening)?

    I had the problem that the brake wasn't centered and it would release but the whole assembly would be offline. i.e. the calipers were rotated and one side was closer (in contact) with the rim.

    If that's the case, then back-off the securing bolt, then using a appropriate (read thin) spanner hold the nut on the other side in a position where the calipers are inline and tighten the bolt again. The usual problem is that the nut is allowed to rotate while tightening, thats the thing to avoid.

    Hope that helps....

    Cheers thanks, no its not a centring problem the brake when squeezed on from the levers on the handlebars just lock the brakes on and there is no release when I let go of the brake levers. FYI its shimano tiagra on this set up
  • dmch2dmch2 Posts: 731
    possibly a silly suggestion - are the mudguards catching on something? Can you pull the blocks away from the wheel?
    2010 Trek 1.5 Road - swissstop green, conti GP4000S
    2004 Marin Muirwoods Hybrid
  • Only thing I can suggest is to check that the spring is properly seated in the calipers. Don't use shimano myself, but on Campag there was a groove that the springs sits in. I found once that the spring had been dislodged after bring transported... you never known!

    Other than that a good dose of WD40 to clean and the lubricate. I had the good fortune to watch several Pro-Tour mechanics at work. Without fail they would lubricate the pivots with the chain oil. I'm not convinced that WD40 is a good lubricant (the hint is in the name, WD=water disperser).

    After that, I have nothing
  • dmch2 wrote:
    possibly a silly suggestion - are the mudguards catching on something? Can you pull the blocks away from the wheel?

    Yes, all fine there.
  • deswellerdesweller Posts: 5,271
    It could be a number of things.

    As you've released the cable tension, perhaps the pip on the lever end is no longer properly seated within the shifter.

    I would also make sure that all my outers are correctly seated and have not come adrift of their cable stops.

    Verify that the calliper is free to move by fully releasing the cable tension and operating it with your hand.
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    On Strava.{/url}
  • It sounds as if the two arms of the caliper are binding. The Defy can have Tektro dual pivot calipers. Perhaps one of the pivots is too tight - try the screw to one side first. Slacken it a little.
  • Looks like the whole mechanism has just seized up. Pretty common on everyday bikes/commuters.
    It's either a strip and rebuild or a new back brake.
    Cheers for the input
    Anyone got a tiagra or similar brake caliper for sale :lol: .
  • dmch2dmch2 Posts: 731
    They're only about £20. I saw somewhere doing £35 for a pair which I was considering as my no name brakes seem to need a tweak to adjust them after every ride and everything else is tiagra.

    How long have you had them?
    2010 Trek 1.5 Road - swissstop green, conti GP4000S
    2004 Marin Muirwoods Hybrid
  • dmch2 wrote:
    They're only about £20. I saw somewhere doing £35 for a pair which I was considering as my no name brakes seem to need a tweak to adjust them after every ride and everything else is tiagra.

    How long have you had them?

    They are just under a year old. Unfortunately no warranty on them. Just checked.

    Wiggle have them for £17.99 each
  • deswellerdesweller Posts: 5,271
    This happened to my rear 105 brake so it is by no means curable by changing to a more expensive calliper. In my case it happened when I was running without mudguards at the end of winter, allowing the wheel to sling a load of salty mud into the calliper pivot.

    It is easily recovered though.

    You will have to run some light oil or WD40 into the pivots and then manually wiggle the calliper around a lot to a) work the oil in between the bearing surfaces and b) clear the muck that has caused it to seize. This will be easier if you take it off the bike again, and you'll avoid getting oil all over your tyre and wheel.

    Once it's free, run some heavier oil (e.g. engine lube or chain oil) into the pivot and give it another wiggle.
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    On Strava.{/url}
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