Leaking Calipers?

costica88
costica88 Posts: 12
edited July 2014 in MTB workshop & tech
Hello,

Since a while ago I noticed a considerable lost in power for my brakes (2013 SLX) after a couple of muddy rides . I removed the pads and as expected they were contaminated. The strange thing is that the pistons and piston seals appeared to be clean. Anyway, I cleaned the pads with some ISA and used some paper grinder and used them for another run. Checked them and again they had a decent amount of oil on them. The issues is happening for both the front and rear brakes.

The thing is the rotors appear to be contaminated and I can't get the oil off with ISA or grinding.

I am completely at a loss as from what the issue might arise. If any can help would greatly appreciate it. Thanks!

Comments

  • The Rookie
    The Rookie Posts: 27,812
    What is ISA?

    You can't clean the pads like that, you have to replace them, once they get hot the contaminants left in the pad wil come back out.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • costica88
    costica88 Posts: 12
    The Rookie wrote:
    What is ISA?

    You can't clean the pads like that, you have to replace them, once they get hot the contaminants left in the pad wil come back out.

    Isoprophylic alcohol.

    Does the oil get so deep in the pads that it resurfaces when they get hot?

    Tbh, I am still trying to figure out for where does the issue come from. I would hate it to changed the pads and realize that the issue was with the calipers.
  • swod1
    swod1 Posts: 1,639
    Take the pads out and use something like a bit of card to expose the pistons and check for any oil leaks ?

    With the rotors if oil is on them and I isopropyl won't clean it off then start again and use some wet n dry to rough up the surface and then bed in a new set of pads.

    If the pads are contaminated then as your likely going to chuck them in the bin you could try heating them up over a gas flame and any oil/grease will burn off.
  • The Rookie
    The Rookie Posts: 27,812
    costica88 wrote:
    The Rookie wrote:
    What is ISA?
    Isopropyl alcohol.
    FTFY - IPA then!
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • costica88
    costica88 Posts: 12
    swod1 wrote:
    Take the pads out and use something like a bit of card to expose the pistons and check for any oil leaks ?

    With the rotors if oil is on them and I isopropyl won't clean it off then start again and use some wet n dry to rough up the surface and then bed in a new set of pads.

    If the pads are contaminated then as your likely going to chuck them in the bin you could try heating them up over a gas flame and any oil/grease will burn off.

    I'll try and do that...how much can the pistons come out? I don't want to do anything stupid and mess things further. Thanks!
  • swod1
    swod1 Posts: 1,639
    just press the leaver lightly with something in the brake like a bit of folded up card etc so the pistons advance out a little bit and you could use a cotton bud or something to rub around it for any trace of mineral oil.
  • Hidrosmen
    Hidrosmen Posts: 6
    swod1 wrote:
    just press the leaver lightly with something in the brake like a bit of folded up card etc so the pistons advance out a little bit and you could use a cotton bud or something to rub around it for any trace of mineral oil.

    So I first cleaned the calipers and pistons for any dirt or oil from the contamination so that things are clean and tidy . Afterwards I squezzed both brakes, maybe 50 times, while checking for any oil residue, but there was close to none. Just very small traces that i think i missed while cleaning. From my point of view I don't see there being any leak.

    My question now is, does the oil/residue from contaminated pads come back out after a ride? I did some tests with the pads. Cleaned them, went for a ride and afterwards they were full of a dark colored substance. Repeated the process severals times and the same happened.

    I'm planning on changing the rotors and pads, and would really hate it to find out later that the issue was other than contamintaed pads.
  • swod1
    swod1 Posts: 1,639
    So just try some new pads but before you do that rough up the disc rotors with some wet n dry course paper and then re bed in the new pads.

    I would try that before going to the expense of buying new rotors or even brakes.
  • cooldad
    cooldad Posts: 32,599
    What's this fad with sanding rotors?
    New ones are nice and smooth - why would you want to roughen them up?
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • swod1
    swod1 Posts: 1,639
    cooldad wrote:
    What's this fad with sanding rotors?
    New ones are nice and smooth - why would you want to roughen them up?

    I mentioned it as the op said they couldn't get oil off the disc but some IPA should have got it off ?
  • The Rookie
    The Rookie Posts: 27,812
    He said he couldn't get it out the pads you twit!

    Hidrosmen, read my first reply - told you it wouldn't work, but you still went ahead anyway. Clean discs, change pads, I'm out.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • swod1
    swod1 Posts: 1,639
    The Rookie wrote:
    He said he couldn't get it out the pads you twit!

    Hidrosmen, read my first reply - told you it wouldn't work, but you still went ahead anyway. Clean discs, change pads, I'm out.

    Yes but there appears to be two people posting about the same issue and the first poster mentioned oil on the rotor, why I suggested doing that.
  • Hidrosmen
    Hidrosmen Posts: 6
    swod1 wrote:
    The Rookie wrote:
    He said he couldn't get it out the pads you twit!

    Hidrosmen, read my first reply - told you it wouldn't work, but you still went ahead anyway. Clean discs, change pads, I'm out.

    Yes but there appears to be two people posting about the same issue and the first poster mentioned oil on the rotor, why I suggested doing that.

    Sorry for the confusion guys..costica88 and Hidrosmen are the same person. I used an old account for the first posting, aka costica88. I'll write on this one from now on.

    @TheRookie, I read your post and I thank you for your advice, but I really want to make sure that the issue is from the pads and not leaky calipers.
  • justin1978
    justin1978 Posts: 18
    my old hope c2's started leaking and got onto the pads and all I did was hold them over a flame for a few seconds and the oil comes to the surface and burns off.
  • swod1
    swod1 Posts: 1,639
    justin1978 wrote:
    my old hope c2's started leaking and got onto the pads and all I did was hold them over a flame for a few seconds and the oil comes to the surface and burns off.

    Yeah that may have worked for you but depends how bad the pads are contaminated.

    Hidrosmen, have you fitted some new pads in the brake to see if its is the pad that is the problem ?
  • costica88
    costica88 Posts: 12
    swod1 wrote:
    justin1978 wrote:
    my old hope c2's started leaking and got onto the pads and all I did was hold them over a flame for a few seconds and the oil comes to the surface and burns off.

    Yeah that may have worked for you but depends how bad the pads are contaminated.

    Hidrosmen, have you fitted some new pads in the brake to see if its is the pad that is the problem ?

    Yes, I've just changed the pads and the issues seem to be gone. Thank you all for your help!

Categories