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Brake nightmare!!!!

Coxy_UKCoxy_UK Posts: 297
edited August 2011 in MTB workshop & tech
Both my brakes are under powered.

I have bled them both numerous times, following instructions and videos. I have replaced the pads in the front and cleaned the discs.

I have replaced the insides of the front lever as a bit had broken, but this hasn't really done much.

I can't, for eample, even lock the backes brake at walking speed!!!

I don't know what the problem can be.

The brakes are Elixir R on my 2009 Stumpjumper.
_______________________________________________________________________________________
Tides of sin draw tighter and brighter, hours become heavier and weighted, and the shadows smile...dark and wild.
<font color="blue">My Stumpy FSR Pic 1</font id="blue">
<font color="red">My Stumpy FSR Pic 2</font id="red">

Posts

  • AnonymousAnonymous Posts: 28,799
    edited July 2011
    Something must be wrong if you can't lock them at walking speed.
    What did you clean the rotors with?
    Are you absolutely positively certain that they've been bled "well"? It's easy to stick the syringes on, but takes a little patience, and a little "knack" to get them done well.

    Also, what size rotors are you using, and how much do you weigh?
  • nicklousenicklouse Posts: 81,520 Lives Here
    what have you used for cleaning?

    how does the lever feel?

    is the rotor being moved by the pads?

    have you let the brakes bed in after the last "adjustment"?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Coxy_UKCoxy_UK Posts: 297
    I weigh about 16st, 160mm rotors, cleaned with Wurth brake cleaner which I've always used and never had a problem.

    Levers feel a little spongy, which makes it easy to say it must just be air in the system, however I have done the bleed process coutless times. I spend a good while degassing the syringe too.

    So I follow the instructions and do it thus;

    Bleed hose pushing caliper syringe, fluid goes into lever syringe.
    Tie lever pulled.
    Bleed caliper.
    Push caliper syringe extending lever back out. At this point instructions always say push until the lever is back in the original position, but you can push more, is it best to stop here or push a little more until you can't push more in?
    Bleed lever.
    Job done.

    Pulling real hard on the back brake while riding didn't lock the wheel but made one hell of a shudder and squeel!!

    Since owning the bike new, no setup has been changed. Discs, calipers, etc, nothing has even been moved.

    The pads do not appear to be moving the discs.
    _______________________________________________________________________________________
    Tides of sin draw tighter and brighter, hours become heavier and weighted, and the shadows smile...dark and wild.
    <font color="blue">My Stumpy FSR Pic 1</font id="blue">
    <font color="red">My Stumpy FSR Pic 2</font id="red">
  • chrisskichrisski Posts: 79
    ive had similar issues with my avids and never with shimano on my other bike so ive come to the conclusion that avids are naff lol

    try a lbs see if they can fix it? but mines be in 4 times and they still no better and my bike is under a yr old!
  • AnonymousAnonymous Posts: 28,799
    In my opinion, Shimano are far far far superior to avids but neither should judder.

    Never heard of this brake cleaner. I've had serious problems using car and motorcycle brake cleaners though, everything from contaminated pads to totally disintigrated pads :shock:
    Try cleaning the rotors with isopropyl alcohol , AND replacing the pads.

    I'll trust your judgement that you've bled them properly, Avids naturally have a slightly "spongy" feel anyway.
  • johnsavjohnsav Posts: 775
    sounds like contaminated pads to me - especially with the juddering

    new pads, clean the rotors with isopropyl
  • chrisskichrisski Posts: 79
    where do u get this isopropyl alcohol from? maplins do it but its quite expensive!
  • gilesjukgilesjuk Posts: 340
    Use meths. it is a degreaser.
  • anjsanjs Posts: 486
    and leaves a residue. IPA from the local chemist of ebay
  • AnonymousAnonymous Posts: 28,799
    gilesjuk wrote:
    Use meths. it is a degreaser.
    No, do NOT use meths. It leaves horrible oily censored behind. IPA does not.

    I honestly don't know where you could buy IPA from, we have a stock of it at work to clean tape heads, so I just pinch some of that.
  • johnsavjohnsav Posts: 775
    yeah chemists usually have some

    we have it in spray cans at work
  • Coxy_UKCoxy_UK Posts: 297
    Wurth Brake and Chain cleaner is indeed intended for motorbikes, and is what I used.
    _______________________________________________________________________________________
    Tides of sin draw tighter and brighter, hours become heavier and weighted, and the shadows smile...dark and wild.
    <font color="blue">My Stumpy FSR Pic 1</font id="blue">
    <font color="red">My Stumpy FSR Pic 2</font id="red">
  • mattl80mattl80 Posts: 80
    Honestly, i had the exact same problems with a set of avids on my old bike, my new kona has shimano slx and not only do they always lock me dead, they are very easy to maintain. I've never had to bleed them yet and i've had them on my bike for 3 years.

    If you've tried everything maybe try selling them and putting some shimano's on.
  • Coxy_UKCoxy_UK Posts: 297
    Well used medium sandpaper to get a good surface on the pads and cleaned everything with isopropyl alcohol... no improvement.

    I want to sell this bike but I don't want to try and sell it with brakes like this. Any would be buyer should be able to expect great brakes.

    I guess I will have to bite the bullet and put it into my LBS tomorrow, that being Stows in Windsor. I've used them in the past with mixed results, but I don't know of anywhere else really around here.
    _______________________________________________________________________________________
    Tides of sin draw tighter and brighter, hours become heavier and weighted, and the shadows smile...dark and wild.
    <font color="blue">My Stumpy FSR Pic 1</font id="blue">
    <font color="red">My Stumpy FSR Pic 2</font id="red">
  • nicklousenicklouse Posts: 81,520 Lives Here
    sounds like they are seriously contaminated. or just cooked.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Coxy_UKCoxy_UK Posts: 297
    Well the front pads were new!
    _______________________________________________________________________________________
    Tides of sin draw tighter and brighter, hours become heavier and weighted, and the shadows smile...dark and wild.
    <font color="blue">My Stumpy FSR Pic 1</font id="blue">
    <font color="red">My Stumpy FSR Pic 2</font id="red">
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