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Persistent snag with rear brakes ...

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  • 11-11-2019 4:38pm
    #1
    skallywag
    Registered Users Posts: 2,987 ✭✭✭


    So, I have a persistent snag with my rear brakes (Ultegra) on my roadbike. It happens every winter without fail.

    Basically, after some time of non-usage (can be just a few days) the brakes stick to the rim after the first pull and do not disengage. I need to physically force open them with my hands. I am now reasonably confident that the snag is due to gunk building up in the portion of cable housing ca 10cm long just before the cable comes out and goes into the brakes. When I jiggle the cable around i.e. force it back and forth with my hand, then after 10 minutes or so the cable seems to move more freely in the housing, and the brakes at least release enough so as not to make contact with the rim.

    So all well and good until the next day when it is a case of rinse and repeat!!

    I know that if I replace the cable/housing it will be fine, but the same snag will always reappear again after some months.

    Anyone else experiencing the same, or any tips on how to avoid it?


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    #2
    8valve
    Registered Users Posts: 976 ✭✭✭8valve


    remove brake pads. check they haven't developed a 'step' on them from catching the edge of the braking surface closest to the hub.

    Remove brake caliper from bike, soak in hot soapy water, clean well with an old toothbrush...or even the current toothbrush of someone you don't like.

    Spray generously with penetrating fluid/lubricant/water displacement spray of your choice. wipe dry with rag.

    Ensure free movement of caliper before refitting to bike.

    Replace inner cable, check outer cable for kinks etc that could impede inner cable travel. flush outer cable with Teflon spray.

    alternatively, replace outer cable and inner cable at same time.


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    #3
    triggermortis
    Registered Users Posts: 2,683 ✭✭✭triggermortis


    Sounds like a cable problem to me. Undo the cable at the brake to check that the brake calliper opens and closes easily. I would bet that if you pull the inner cable all the way out you’ll find a part of it corroded or even frayed, and this is what’s causing the brake to stick on. New inner cable will sort this problem


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    #4
    07Lapierre
    Registered Users Posts: 8,219 ✭✭✭07Lapierre


    IMO It's the caliper. It needs to be disassembled, cleaned, lubed and reassembled.

    https://www.youtube.com/watch?v=TqbCR83psAg


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    #5
    skallywag
    Registered Users Posts: 2,987 ✭✭✭skallywag


    Thanks for the advice guys.

    Brake pads look good.

    I shall remove the cable and take a look, ditto for the caliper.

    When I pull on the inner cable with a pliers, in order try to free things up and to force the caliper open again, I expose a few extra mm's of the inner cable, which does indeed look corroded.

    Anytime I have taken the bike to my local shop he has just shrugged and said you need a new cable (and has replaced both inner and outer housing), things have worked perfectly for some months, but the same snag has always reappeared. Hence perhaps the caliper is indeed at fault and needs to be overhauled. Up to now I have taken the lazy approach of spraying WD40 everywhere into the housing and in between the gaps in the caliper, though maybe this has made things worse, who knows (thinking gunk build up inside the housing).


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    #6
    Brian?
    Moderators, Recreation & Hobbies Moderators Posts: 20,883 Mod ✭✭✭✭Brian?


    Drop of oil in the spring. Done

    they/them/theirs


    And so on, and so on …. - Slavoj Žižek




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    #7
    skallywag
    Registered Users Posts: 2,987 ✭✭✭skallywag


    Brian? wrote: »
    Drop of oil in the spring. Done

    Well I WD40'd the hell out of it and it did not really make a difference, will oil make a noticeable difference I wonder?


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    #8
    magicbastarder
    Moderators, Category Moderators, Arts Moderators, Sports Moderators Posts: 48,477 CMod ✭✭✭✭magicbastarder


    i'm curious as to how your cables rust so quickly; do you have mudguards?


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    #9
    Midster
    Registered Users Posts: 322 ✭✭Midster


    Hi check these,

    1) Are the brake pads contacting the rim itself, as sometimes when pads are worn they can get stuck under the rim part of the wheel.
    2) Check the brake pads are securely tightened to the calliper, sometimes if they move it can have the same effect as number 1.
    3) Release the cable from the calliper completely and squeeze the brakes together with your hands to see if they also stick by doing it that way.
    4) Check the cable cover itself for any sort of kinks and be very critical with your eye, some bikes to be honest are designed badly and do not allow for gentle curves in the cable. If there is to severe curve anywhere, the cable housing will always kink there first.
    5) Sometimes road dirt and general grit can block either the top or bottom of a cable housing, if you ride your bike in wet weather for example and store it in a dry place after, sometimes that dirt and grit can dry and stop the cable from moving, so release the cable from the callipers and slide the cable housing down the cable until you can see the part of the cable previously covered by the housing, use spray lubricant (never oil) on the cable itself and slide the housing up and down the cable to soften any crap that might be in there, also spray on the entrance to the housing as you slide the housing back to its original position.
    6) Lastly, check the brake levers, again you’ll need to release the brake cable from the brake callipers, most brake levers have springs inside so when you pull them (without there being a cable) they will go back to there original ready position on there own, if they don’t, try spray lubricant, and if that doesn’t work, and it doesn’t look like there’s anything else you can do, go buy some new (newer) ones.


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    #10
    skallywag
    Registered Users Posts: 2,987 ✭✭✭skallywag


    Nope, no mudguards.

    What I find odd is that it always seems to be only the rear housing/cable on the rear brakes, I never have had an issue with the front brakes. Plus, I would never really ride much when it is wet.


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    #11
    Midster
    Registered Users Posts: 322 ✭✭Midster


    skallywag wrote: »
    Nope, no mudguards.

    What I find odd is that it always seems to be only the rear housing/cable on the rear brakes, I never have had an issue with the front brakes. Plus, I would never really ride much when it is wet.

    Some bikes are designed with the cable routes as an after thought, it’s possible that between the brake lever and the brake callipers either the cable housing has kinked, or that the cable itself may have become kinked, or worse, both, check my tips and be thorough to identify and eliminate the problem.

    It should only be a 5 or ten minute job.


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    #12
    skallywag
    Registered Users Posts: 2,987 ✭✭✭skallywag


    Cheers again guys. Pads themselves are not the culprit I believe, I have checked them in detail.

    So my next step I believe is to narrow it down to cable/housing gunk versus caliper itself.


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    #13
    Brian?
    Moderators, Recreation & Hobbies Moderators Posts: 20,883 Mod ✭✭✭✭Brian?


    skallywag wrote: »
    Well I WD40'd the hell out of it and it did not really make a difference, will oil make a noticeable difference I wonder?

    WD40 isn't really a lubricant that lasts. It'll get things unstuck but oil keeps them lubricated.

    Take the caliper off the bike and squeeze it closed with your hand. Is it now stuck? Probably, add some oil to the spring and move it a few times by hand. It'll work it's way free and stay free.

    they/them/theirs


    And so on, and so on …. - Slavoj Žižek




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    #14
    Midster
    Registered Users Posts: 322 ✭✭Midster


    Brian? wrote: »
    WD40 isn't really a lubricant that lasts. It'll get things unstuck but oil keeps them lubricated.

    Take the caliper off the bike and squeeze it closed with your hand. Is it now stuck? Probably, add some oil to the spring and move it a few times by hand. It'll work it's way free and stay free.

    Actually your wrong there, oil is the last and the worst thing you can use. The reason is that dirt sticks to it like a magnet, after a time it can cause another problem we’re whatever you put it on can stop working, and then you have to dismantle that part and use a bush to get it off.

    I used to work in a professional bike shop and the only place grease was ever used was for loose bearing type wheels, and loose bearing type cranks.

    My advice, don’t use it, it’s more trouble than it’s worth.


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    #15
    Brian?
    Moderators, Recreation & Hobbies Moderators Posts: 20,883 Mod ✭✭✭✭Brian?


    Midster wrote: »
    Actually your wrong there, oil is the last and the worst thing you can use. The reason is that dirt sticks to it like a magnet, after a time it can cause another problem we’re whatever you put it on can stop working, and then you have to dismantle that part and use a bush to get it off.

    I used to work in a professional bike shop and the only place grease was ever used was for loose bearing type wheels, and loose bearing type cranks.

    My advice, don’t use it, it’s more trouble than it’s worth.

    I didn't say use grease? I said use oil. Oil is perfect for this job.

    they/them/theirs


    And so on, and so on …. - Slavoj Žižek




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    #16
    Midster
    Registered Users Posts: 322 ✭✭Midster


    As any good bike mechanic will tell you, using oil or grease as a lubricant on a bycicle is a bad idea. It attracts dirt and grit, which with repeated use will cause problems later on.


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    #17
    Brian?
    Moderators, Recreation & Hobbies Moderators Posts: 20,883 Mod ✭✭✭✭Brian?


    Midster wrote: »
    As any good bike mechanic will tell you, using oil or grease as a lubricant on a bycicle is a bad idea. It attracts dirt and grit, which with repeated use will cause problems later on.

    What do you put on your chain?

    they/them/theirs


    And so on, and so on …. - Slavoj Žižek




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    #18
    Midster
    Registered Users Posts: 322 ✭✭Midster


    Brian? wrote: »
    What do you put on your chain?

    Spray lube, it keeps the chain moving correctly, while making it easy to clean.


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    #19
    secman
    Registered Users Posts: 6,238 ✭✭✭secman


    I had a similar problem with the rear brake, the mechanic changed the cable on a couple of occasions, but after a month or so it reverted to a gritty feel on the pull of the lever. Eventually changed the cable housing and its working nice and smooth...its a winter bike so time will tell.


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    #20
    skallywag
    Registered Users Posts: 2,987 ✭✭✭skallywag


    So, finally got around to going at the problem.

    Loosened the bolt which holds the cable in place and the calipers spring open with a wallop. Spring action is working perfectly well.

    So it must be gunk / corrosion on the damn housing. Pulled it about a fair bit and re-tightened the bolt, all looking good. For now.


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    #21
    Midster
    Registered Users Posts: 322 ✭✭Midster


    skallywag wrote: »
    So, finally got around to going at the problem.

    Loosened the bolt which holds the cable in place and the calipers spring open with a wallop. Spring action is working perfectly well.

    So it must be gunk / corrosion on the damn housing. Pulled it about a fair bit and re-tightened the bolt, all looking good. For now.

    If you know what a brake adjuster is and what it looks like, before you re attach the cable make sure the adjuster is about half way out, then hold the pads together against the wheel while you hold the cable tight and tighten the bolt(you may need more than one pair of hands) then screw the adjuster back in again so the pads loosen there grip on the wheel. And ideal re attachment leaves you with half a pull on the brake leaver on the handle bars until the wheel locks up.
    If your wheel is slightly buckled, then you will have to screw in the adjuster a bit further to compensate.
    And if one brake pad is resting against the wheel more than the other, there should be a small Allan key adjuster on the calliper itself, tighten one, or loosen the or you may have to do both till the gap between the pads and the wheel is the same one both sides.
    If you have a buckle, this is more tricky, it maybe prone to rubbing whatever you do, just do the best you can with it and think about maybe getting it straightened, but only if it’s worth the money to do it.


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    #22
    skallywag
    Registered Users Posts: 2,987 ✭✭✭skallywag


    Midster wrote: »
    If you know what a brake adjuster is and what it looks like

    Cheers.

    I am assuming that this is a a 'screw' type thing which I can open or close, positioned after the cable housing, and not too far away from the calipers.

    As for how to prevent this problem happening year in year out, anything that I can do there? Any tips on avoiding gunking up the cable?


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    #23
    Midster
    Registered Users Posts: 322 ✭✭Midster


    skallywag wrote: »
    Cheers.

    I am assuming that this is a a 'screw' type thing which I can open or close, positioned after the cable housing, and not too far away from the calipers.

    As for how to prevent this problem happening year in year out, anything that I can do there? Any tips on avoiding gunking up the cable?

    Yes the brake adjustment screw should be on the calliper itself. There should be 2, one big one to remove the calliper itself, and a smaller second one.
    The parts of cabling were the bear cable goes inside the cable cover, first I look at which way the cable moves when I pull and release the brake, then spray WD40 with the straw on the parts of the cable that goes back inside the covering when the brake leaver is either released or pulled, as well as the entrance the the cable covering itself.
    This should help stop dirty road water getting inside.
    Although no solution is forever, eventually either the cable or the cover will need replacing whatever you do.


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