Rear brake suddenly slack

keithc440
keithc440 Posts: 277
edited December 2007 in Workshop
Just been applying a bit of lube to the rear brake cable after washing the bike, gave the lever a few tweaks to spread it about and all of a sudden the braking action slackened off dramatically. It will still stop the wheel but not adequately so I will have to adjust it. Puzzled as to why this should suddenly happen all of a sudden. Thought I may have knocked the adjuster switch on the rear caliper but this was not the case. Anyone any idea what happened ? I am running Dura Ace 9 speed levers and 105 calipers.

Comments

  • feel
    feel Posts: 800
    did the cable slip slightly?
    We are born with the dead:
    See, they return, and bring us with them.
  • keithc440
    keithc440 Posts: 277
    Didn't notice any cable slip. Was thinking I am going to have to adjust it by tightening the cable. Is this best done as a 2 person job so the second person can clamp the calipers together whilst you use plyers to pull the cable through and then tighten ?
  • blackhands
    blackhands Posts: 950
    You shouldn't need pliers - just loosen off the cable clamp (5mm allen key) then undo the cable barrel adjuster a couple of turns anti clockwise. Squeeze the brake blocks onto the rim with one hand and pull the cable taught with the other then tighten up the cable clamp whilst keeping the brake squeezed. If you've overdone it so that the brake rubs, firstly make sure its centered properly - if it is, then the brake needs loosening off, so turn the barrel adjuster clockwise.
  • keithc440
    keithc440 Posts: 277
    Thanks Blackhand I have learnt something there. Just followed your instructions and jobs a good un. Don't want to be riding on these roads with a poor back brake. Can only conclude that the cable must have slipped slightly.
  • feel
    feel Posts: 800
    Keith if your brakes are still not as good as they should be try cleaning the rims with a degreaser and finish off with some wire wool. Was amazed the other day how much crap was stuck to my rims and the brake blocks. Cleaning them made a big difference to my braking. If you remove your blocks for cleaning remember to angle them in at the front slightly when refitting otherwise they might judder or squeak.
    We are born with the dead:
    See, they return, and bring us with them.
  • robbarker
    robbarker Posts: 1,367
    Did you knock the quick release (the small lever on the calipers that allows the wheel to be removed without the tyre fouling the brake shoes)?
  • richa
    richa Posts: 1,632
    robbarker wrote:
    Did you knock the quick release (the small lever on the calipers that allows the wheel to be removed without the tyre fouling the brake shoes)?

    My thought as well. Would explain why it suddenly became slack.
    Rich
  • andrew_s
    andrew_s Posts: 2,511
    Maybe the cable outer wasn't previously seated properly in the lever, caliper or one of the cable stops? If the outer was caught on the edge of a stop, and dropped fully in when the lever was being waggled, that would explain things.
  • robbarker
    robbarker Posts: 1,367
    You might have hit the nail on the head Andrew - I didn't read Keith's message thoroughly enough - he mentioned "adjuster switch", probably meaning the same thing that I meant by "quick release". You'd think a badly seated outer would show itself quite quickly though? I wonder if the cable was recently installed?
  • turkeytickler
    turkeytickler Posts: 640
    Are you positive this happened _precisely_ after you applied the lube? I only ask because I lost a _huge_ amount of rubber off of my rear pads at the weekend (not to mention my rear rim) due to grit, and the gain in lever travel was really noticeable.....

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