Brakes squealing

Discussion in 'Thumpers' started by djchan, Mar 26, 2006.

  1. djchan

    djchan Long timer

    Dec 9, 2004
    on the border
    The front brake on my 02 LC4E has begun to squeal although braking effectiveness is maintained. There's plenty-o-pad left so I suspect a contaminant. What do you guys use to clean your discs? As a sidenote - my left fork seal is leaking - so that may explain the contaminant. Fork seals are scheduled for replacement next week, but what can I do in the meantime.

  2. Buckster

    Buckster Banned

    Jul 23, 2004
    Atlanta GA or London UK
    LC4 Brakes squeal, the only cure is to loosen the axle clamps, apply the brakes and bounce it on the forks a few times to centre the discs to the calipers, then retighten the clamps. Even then they may still squeal.
  3. Arch

    Arch Incurable Gearhead

    Dec 30, 2001
    Katy, TX
    Dean, at first I'd do all the usual things to make it go away, then I gave up worrying about the squeal long ago. :lol3 BTW, before you have the seal replaced, carefully lift and clean under 'em with some film or something similar. More often than not, that takes care of it.
  4. creeper

    creeper Still alive...

    Dec 13, 2003
    Puget Sound
    First... the seal thing. As Arch indicated... KTM seals seldom fail, but they do get crap in them, which you can clean out. To eliminate (usually) any further leaks... try this.

    Push down the dust seals... don't try to lever them off on the lip, there is no reinforcement there and you'll tear them. You have to pull the lip down then push in and rotate with a wide, screwdriver or similar tool.

    You have to push a screwdriver or similar tool in between the lip (B.) and the fork upper leg and push into the seal surface (B.)... then lever the seal down.


    I try to pry straight up and down and take small "bites"... maybe 6 or 7 little bites as I go around the seal. It's a bit fussy, but I've never damaged a dust seal.

    Once those are down, you need to clean the schmutz out of the oil seals.
    I use a new white business card rather than a piece of 35mm film... you can see the contamination on the white card and have a good idea of when you've gotten all of it out. Just push a corner up into the seal about a 1/2 inch and go around a time or two until the card comes back clean.

    Once everything is clean, pack the dust seals with medium body waterproof grease and install them. BelRay waterproof, Motorex 2000... something along those lines.
    Stroke the forks, wipe off the excess a few times and your done. The forks should never leak again as the grease in the dust seal acts as a crap trap to collect the grit before it reaches the seal.


    Now... on to the brake squeal.

    Keep in mind, what occured below is a condensed reprint of something I did months ago and on a specific bike... a 2003 640 Advenure with a 21' wheel and 320mm brake rotor, one of the few bikes made with this combination. The only other that comes to mind is the late model KTM 660 Rallye.

    This is to be considered an option, an alternative, a suggestion, a band-aid.... not an endorsement.

    EBC brake shims.


    Now we’ve all heard of the legend of homemade “brake shims”. If you’ve been around long enough, you may have contributed to that legend yer’self. I’ve made brake shims out of manila folders, printed circuit board, copper sheeting, inner tubes… you name it and I made a brake shim, that usually didn’t work, out of it.



    Product Advantages: Does this that and the other thing. Noise resistant.

    Material Specification: Fiberglass (1) and rubber (2) laminate with adhesive backing.

    Fitting instruction: Cut with scissors, peel and stick.

    To be as true a test as I can muster, I decided to remove the less noisy EBC pads with 7K miles on them and reinstall the most noisy, original Brembo pads with less than 2K miles on them. I know this is not representative of someone with relatively new pads and discs… but it’s what I have.

    To remove the old pads, and make room for the even older and thicker pads and shim, I pressed against the caliper body with my knee until the caliper was sloppy loose on its floating pins.
    (If you have fixed calipers and floating rotors… you can do this until your knee explodes... make sure to take pictures)

    I never stopped to do a stare and compare when I installed the EBCs… the Brembos are dimensionally longer than the EBCs.
    Brembos on the right, EBCs on the left.


    The back of the piston side Brembo pad.


    Note that I installed a shim ONLY on the piston side pad… there are only three narrow “ears” against the inner pad and I didn’t like the idea of putting three skinny strips on it. The instructions don’t specify… I imagine if you had a 2 or 4 opposed piston type caliper you would install them on both sides.


    Reassemble the brake, pump the fluid back to a firm lever… and go for a ride.


    And we’re back! So, howzitworkyouask?

    Low speed (35mph) stops with light pressure – no noise.
    Low speed stops with high pressure – no noise.
    High speed (75mph) stops with light pressure – no noise.
    High speed stops with high pressure – no noise.
    Brake "feel" was quite firm... not rubbery, as I had expected.

    As this “test” was performed under specific conditions, with parts with X wear, how any of this will be applicable to other KTM brakes, or for that matter any bikes brakes remains to be seen.

    Is it worth while giving it a try? Your call.

    That’s all folks,
  5. clintnz

    clintnz Trans-Global Chook Chaser

    May 17, 2004
    Rotoiti, North Is, New Zealand
    Hmmm... Interesting. I never had much noise with the stock pads, I replaced them with some hard compound SBS pads recently 'cos they were what the shop had, & now they are bloody rowdy. I think I might order some soft ones & maybe try those shims too.

  6. drmax

    drmax Been here awhile

    Sep 3, 2005
    Martinsville, IN
    Dean, this is exactly my issue. Squeeking front and rear brakes, but only when coming up to a slowed, rolling stop. Never a noise until my feet touch down. Also, my left front fork seal is showing slight signs of leakage. My yr is '02 as well. Did you clean or replace seal? What about brakes?
    I will try to clean 1st. Thx for the info. Greg
  7. herobikes

    herobikes HE AINT HEAVY HES MY LC4

    Apr 28, 2005
    Same here , replaced stock worn pads with ebc mx-s and they now howl like George Bush when asked about his Iraq exit strategy.