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Thread: Preventive maintenance: check your road disc brake pad bolt/pad axle

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    Default Preventive maintenance: check your road disc brake pad bolt/pad axle

    Hate to give another arrow for the "disc brakes are too complicated/need too much maintenance" crowd, but I got a little squeal in the rear caliper last week--Ultegra 8070--and decided to pull the pads for a proper cleaning. The bolt/axle that keeps the pads in place (and has its own retaining clip) was so tightly bonded/corroded that it fought mightily to get out and deformed upon removal. A few days later same thing happened to one of our customers on a bike with only a couple thousand miles on it (mine is about 2 years old), only his bolt failed completely. Customer is a toxic sweat guy; I sweat pretty heavily but haven't had the corrosion issues some do. Anyway, not a bad idea to crack these open and give a touch of grease or antiseize to threads. This is going to start showing up as these systems start to age.
    am I the only Marvin?

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    THANK YOU I will do that today.

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    I drill out a half dozen of these every year. It’s usually a pain to salvage the caliper at all, and almost always results in no more threads in the eyelet, a cotter pin in place of a once-classy retainer bolt.

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    The black pins are steel versus alloy like the silver ones. Can’t remember having to drill one? Silver? yeah a few times- it sucks

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    Quote Originally Posted by Applesauce View Post
    a cotter pin in place of a once-classy retainer bolt.
    i remember when these were the norm. i need to source some to keep on hand.
    -Dustin

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    Until shimano/anyone else starts offering a replacement for the retention clips that go with the pin I’ll be happy to keep using cotters. The amount of bikes that come through missing those is terrifying

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    My name is Peter Miller.

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    A wise mechanic would use the right tools on the first installation.
    Because there is a bit of a problem with the Shimano disk stuff, in terms of small fixtures that are overtightened from the factory.

    The bleeding port on the shifters does use a 2mm allen key which is not sufficient to release the bolt from the original torque. I've seen countless of those been rounded off, so we always keep a few spare ones in stock.
    Most 2mm allen keys won't do the job there, so you'll have to use one of those magic Wera Hex-Plus, or do yourself a favour and get this cheap one that appears to be slightly oversized and it's a tight fit (you have to really push it in to fit the 2mm hex); it's also very useful on those stubborn grub-screws of Shimano/Swissstop rim brake pads.

    Another annoying one is the bleeding nipple at the caliper. Both types with the 6mm bolt or the 3mm allen, they're set too tight from factory. To avoid a shower of brake fluid on your first installation, make sure you crack them open, and gently close, before you've placed the funnel and fluid at the shifter.


    Last one, as per the OP, the pin to retain the Shimano disk pads. How silly is to use a slotted screw that requires a 0.8mm screwdriver? 99% of the average tools are 5.5 or 5.0mmx1.0. If you're lucky to have a 5x0.8 flat screwdriver you can check on those silly pins: it makes all the difference.
    If you don't have one, and can remove the pin, don't be afraid of leaving it aside and replace with a split-pin of the correct size. Pliers never fail to remove them, and they're a proven design in their simpliciy.
    Andrea "Gattonero" Cattolico, head mechanic @Condor Cycles London


    "Caron, non ti crucciare:
    vuolsi coś colà dove si puote
    cị che si vuole, e più non dimandare"

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    Quote Originally Posted by Gattonero View Post
    The bleeding port on the shifters does use a 2mm allen key which is not sufficient to release the bolt from the original torque. I've seen countless of those been rounded off, so we always keep a few spare ones in stock.
    Is it just me, or do these look almost like T8 fittings? In any case, I don’t know why they went away from 2.5mm.

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    Either way the alloy is soft enough that hammering in a t10 gets most of the very stuck ones loose

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    Quote Originally Posted by Applesauce View Post
    Is it just me, or do these look almost like T8 fittings? In any case, I don’t know why they went away from 2.5mm.
    A T8 fits but the bolt looks more a proper 2mm Hex. However, the real problem is that are way too tight from the factory: the levers arrive empty, so why on earth they screw the bleeding cap SO damn tight? There's no bloody oil in the first place!

    T8 driver in the bleeding cap, it's a nice fit


    but the cap shows the parallel sides of a 2mm Hex



    This is the pin to retain the pads on Shimano calipers.

    A standard "1.0mm" screwdriver/bit doesn't fit well


    note how this Wiha 0.8mm x 5.5mm goes all the way with a proper fit
    Andrea "Gattonero" Cattolico, head mechanic @Condor Cycles London


    "Caron, non ti crucciare:
    vuolsi coś colà dove si puote
    cị che si vuole, e più non dimandare"

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    J kit sets come filled with oil

    Regardless it’s a good idea to have a few extra caps. I replace one every once in a while that someone has hamfisted

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    It doesn't really matter whether the lever comes as a kit or not, there really is no need to get those fixtures so tight in the first place.
    Andrea "Gattonero" Cattolico, head mechanic @Condor Cycles London


    "Caron, non ti crucciare:
    vuolsi coś colà dove si puote
    cị che si vuole, e più non dimandare"

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    This is true. should never need anything other than a 2mm driver to service them

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    Default Re: Preventive maintenance: check your road disc brake pad bolt/pad axle

    Quote Originally Posted by Applesauce View Post
    Is it just me, or do these look almost like T8 fittings? In any case, I don’t know why they went away from 2.5mm.
    The manual mentions 2 mm hex but is also explicit about not using a ball end key. I don't know why it's so difficult to make bolt heads properly...
    Chikashi Miyamoto

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