Disc brake lost performance

Discussion in 'Cycling Equipment' started by Candt, Jul 22, 2003.

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  1. Candt

    Candt Guest

    After a particularly liberal use of bike cleaner and water dispersant, the bike looks great - but I
    think I've contaminated my disc pads. The brakes feel right
    - in that the levers still hit the hard resistance after an inch, theres no spongy feel, but the
    front and rear will just not lock up at all.

    I've removed the pads, and cleaned with methylated spirits, and the rear is a little better, (I can
    skid now), but the front just doesnt want to provide that 'throw-me-over-the-bars' type stopping
    power like it used to.

    I've cleaned the rotors with a proprietary disc rotor cleaning spray, and when I removed the pads,
    theres no extraneous mineral oil or other visible contamination. The fact that both brakes were poor
    when I rode on Sunday leads me to believe it was my cleaning that did it..

    Any tips for cleaning the pads, or am I going to have to replace them...??

    Cheers,

    CandT
     
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  2. Shaun Rimmer

    Shaun Rimmer Guest

    CandT <[email protected]> wrote in message
    news:[email protected]...
    > After a particularly liberal use of bike cleaner and water dispersant, the
    bike
    > looks great - but I think I've contaminated my disc pads. The brakes feel
    right
    > - in that the levers still hit the hard resistance after an inch, theres
    no
    > spongy feel, but the front and rear will just not lock up at all.
    >
    > I've removed the pads, and cleaned with methylated spirits, and the rear
    is a
    > little better, (I can skid now), but the front just doesnt want to provide
    that
    > 'throw-me-over-the-bars' type stopping power like it used to.
    >
    > I've cleaned the rotors with a proprietary disc rotor cleaning spray, and
    when I
    > removed the pads, theres no extraneous mineral oil or other visible contamination. The fact that
    > both brakes were poor when I rode on Sunday
    leads
    > me to believe it was my cleaning that did it..
    >
    > Any tips for cleaning the pads, or am I going to have to replace them...??
    >
    > Cheers,
    >
    > CandT

    Hey there - It does indeed sound like you've got some crap on them that they don't like. What I did
    with mine when I got them _covered_ with fork oil (leaky fork seal - happened a few times before I
    sorted it), was I took the pads out, scrubbed them with dishwash liquid and water, heated them with
    a hot air gun (blow torch will do, but _don't_ over do it or the pad material _will_ separate from
    the metal), then I sanded the surface. I cleaned the rotor with nothing more than dishwash liquid,
    hot water, and a green plastic pan scrub.

    I put it all back together, and covered the rotor with fine (stone free!) wet mud. Rode, braked,
    more mud - repeat until they bite again.

    Like I said, the problem happened a few times, and each time, this saw me regain full brake
    performance (Hope Mini).

    HTH!

    Shaun aRe
     
  3. Candt

    Candt Guest

    On Tue, 22 Jul 2003 10:20:50 +0100, "Shaun Rimmer" <[email protected]> wrote:

    >
    >HTH!
    >
    >
    >
    >Shaun aRe
    >
    >
    >
    >
    >

    Help, yes - what I wanted to hear, no ;-)

    better crack out my scrubbing brush I guess.... I've got no blowtorch, but will a gas burner of a
    cooker work? I could use pliers to keep it at arms length...

    Cheers

    CandT
     
  4. Doug Huffman

    Doug Huffman Guest

    Find a good hill and heat the hell out of your brakes. Three or four hard stops from 50 mph on my
    forty-ish pound bike carrying my 220 pounds and the crap is cooked out. The first one will be scary
    due to the contamination but things will get better. The distributors know about this considering
    that they're charging $20 for what used to be $10 pad sets.

    "CandT" <[email protected]> wrote in message
    news:[email protected]...
    > After a particularly liberal use of bike cleaner and water dispersant, the
    bike
    > looks great - but I think I've contaminated my disc pads. The brakes feel
    right
    > - in that the levers still hit the hard resistance after an inch, theres
    no
    > spongy feel, but the front and rear will just not lock up at all.
    >
    > I've removed the pads, and cleaned with methylated spirits, and the rear
    is a
    > little better, (I can skid now), but the front just doesnt want to provide
    that
    > 'throw-me-over-the-bars' type stopping power like it used to.
    >
    > I've cleaned the rotors with a proprietary disc rotor cleaning spray, and
    when I
    > removed the pads, theres no extraneous mineral oil or other visible contamination. The fact that
    > both brakes were poor when I rode on Sunday
    leads
    > me to believe it was my cleaning that did it..
    >
    > Any tips for cleaning the pads, or am I going to have to replace them...??
    >
    > Cheers,
    >
    > CandT
     
  5. Shaun Rimmer

    Shaun Rimmer Guest

    CandT <[email protected]> wrote in message
    news:[email protected]...
    > On Tue, 22 Jul 2003 10:20:50 +0100, "Shaun Rimmer" <[email protected]> wrote:
    >
    > >
    > >HTH!
    > >
    > >
    > >
    > >Shaun aRe
    > >
    > >
    > >
    > >
    > >
    >
    > Help, yes - what I wanted to hear, no ;-)

    Why? - I told you that your pads are likely reclaimable.......

    > better crack out my scrubbing brush I guess.... I've got no blowtorch, but
    will
    > a gas burner of a cooker work? I could use pliers to keep it at arms
    length...

    Yes, but as I mentioned (and I stress this!), do _not_ get the pads too hot! I used pliers and held
    over a gas cooker the first time, and managed to burn all the oil off. Brakes worked _perfectly_
    straight off, until my 3rd or 4th hard braking test, when the friction material separated form the
    metal and launched across the street - I'd damaged the glue/resin/stuff that holds them on with the
    heat (why I used an air-gun the last times).

    It's possible the mud alone will work (it _is_ quite miraculous in its brake bedding/contamination
    removing properties - at a _guess_, I'd say it abrades the surfaces (well, not guessing here!), and
    as it dries, absorbs the oils a little before dropping/flaking off).

    Shaun aRe
     
  6. Doug Huffman

    Doug Huffman Guest

    Yep. Aluminum foil

    "David Kunz" <[email protected]> wrote in message news:b%aUa.119312>
    > I ended up making a disc cover for my rear rotor so that when I clean my chain, the cleaner/old
    > chain oil don't get on it.
    >
    > David
     
  7. [email protected] (Doug=A0Huffman) wrote:

    >Find a good hill and heat the hell out of your brakes. Three or four hard stops from 50 mph on my
    >forty-ish pound bike carrying my 220 pounds and the crap is cooked out. The first one will be scary
    >due to the contamination but things will get better. The distributors know about this considering
    >that they're charging $20 for what used to be $10 pad sets. "CandT"

    This was a joke, right? you aren't actually suicidal enough to descend like this on less than
    perfect brakes?!

    May you have the wind at your back. And a really low gear for the hills! Chris

    Chris'Z Corner "The Website for the Common Bicyclist": http://www.geocities.com/czcorner
     
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