Brakes keep locking up-any ideas?

Mendip rouleur
Mendip rouleur Posts: 163
edited March 2011 in Workshop
I know this is probably obvious-if you know the answer, but I just changed my blocks on the rear wheel of my road bike and now even though there is plenty of clearance on the rim, the brakes lock on the wheel when I pull on the lever.

Same blocks, cables fine and oiled, plenty of play in the spring.

Any ideas? Sorry if this is obvious.

Thanks
“I ride my bicycle to ride my bicycle.”

http://mendiprouleur.blogspot.com/

Comments

  • A few questions;

    What brakes are they?

    Did you tighten the pivot bolts or frame fixing bolt?

    If you squeeze the caliper with your hand does it return?
  • Pivot bolt needed adjusting, brilliant thanks
    “I ride my bicycle to ride my bicycle.”

    http://mendiprouleur.blogspot.com/
  • Grifteruk
    Grifteruk Posts: 244
    I dont want to hijack this thread, but looks like OP got his problem solved yet I am still having a problem with mine.

    I changed out the brake blocks entirely and refitted with new. I adjusted the cable tension to give good clearance and the rear seems to work fine, but the front block seem to stick after pulling brake lever.

    the brake lever is returning to the proper position once i release it but it seems like the brake itself is not releasing fully. I can pull it apart easily with my hand to free up the wheel, but it wont do it on its own. It releases some of the way, but not all. I have cleaned the brakes but am not sure what else it could be?

    As a newbit to fiddling with brakes, any ideas gratefully received in advance of what could be a short, painful ride on Sat am otherwise!!
  • Butterd2
    Butterd2 Posts: 937
    My guess would be the cable is sticking in the outer. If you have adjusted the cable tension then you could now have a bit of "dirty" cable that used to sit outside of the outer now pulling into it and sticking.
    Release the cable and work a bit of WD40 or chain oil into it, that should free it up.
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  • racingcondor
    racingcondor Posts: 1,434
    Grifter, I'd go with the cable sticking as well but it could be the brakes themselves. Couple of things to think about -

    1) If the brakes are dirty or have seen a lot of road salt recently they may be gummed up or corroded enough that they're not releasing properly. you can fix that with a good clean and generous dousing in WD40.

    2) Tight bends in the cable housing is likely to cause some stickyness in the cables.

    Personally I squeeze a little heavy grease onto my finger and run the cable through that so that you can barely see the coating of grease (too much and it might start clogging the cable housing up). A light lube (teflon spray like GT85 or chain lube) would probably work just as well.
  • keef66
    keef66 Posts: 13,123
    You can easily tell if it's the brake caliper or the cable or both by separating them.
    With the cable no longer attached to the caliper, squeeze the caliper by hand to press the blocks against the rim. Does it release and centre itself properly when you let go?
    If no, it suggests the caliper itself needs taking apart, cleaning, lubricating and reassembly.

    If yes, the fault must lie with the cable. Whip out the inner cable, give it a clean and examine it carefully. Any kinks, rust or broken strands then replace it. If it looks OK, then a very light greasing as racingcondor describes, and rethread it.

    Any difficulty rethreading it may suggest a problem with the outer. Cheap enough to replace too, but a bit more hassle.

    HTH