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Thread: Pads leaving weird deposits on rotors- see photo's

  1. #1
    NSW supra club Member
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    Pads leaving weird deposits on rotors- see photo's

    Hey guys.
    Recently at a track day(smsp), i went to try out my new brake setup that i installed, but immediately i was feeling weird brake vibration/shudder before i could even start bedding them in! So even tho it was causing issues pretty much straight away, i continued to bed them in as per winmax/circo instructions for the first session.
    During the day, it didnt improve and was very bad at vibration the whole day.

    The car is a 1450kg supra.
    Brakes are 6/4 pot brembos with circo m119 pads.
    Still using boosted brake system.
    Rotors were brand new 360mm.
    Air ducting.
    The dba paint temp hardly reached a tuch over 500deg.

    I removed the circo pads, sanded down the rotors as much as possible, put standard oem brembo pads this time...and issue went away, rotors cleaned up even more and no vibration/shudder with these pads.

    Anyone know or have an idea what that looks like? What is causing it?

    Ive attached the photo of the fronts
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    93 tt supra,black 6 speed
    --------------------------------
    SINGLE

  2. #2
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    At the risk of being Captain Obvious, the vibration was caused by the deposits on the rotor, in the brake trade they call it "disk thickness variation".

    As for what caused it with those Circo pads, my first suggestion would be incorrect bedding in procedure, for either the new pads or the new rotors, or both. Check with both suppliers.

    FWIW, I fitted some new road pads to the tow car right before we went down to Winton a few months back. By the time we got 100k out of town, the shaking under brakes was so bad, I was convinced I hadn't done the wheel nuts up properly, and we were about to lose a wheel. It must have been some sort of incompatibility between the deposits left by the old pads and the new ones. After about 500k and a few more brake applications it sorted itself out.

  3. #3
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    Bedding procedure got rotors too hot too soon OR you've parked up with the rotors still hot (farkin hot) and the result is pad deposits ........ need to do much more brake cooling after session.

    Actually, reread you original post .......... bed new rotors with old pads ............ bedding new rotors with new pads is going to cause a problem
    Last edited by BGTV8; 06-11-17 at 05:37 AM.

  4. #4
    Registered User Stevil's Avatar
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    Yep most likely incorrect bedding, and got too hot too quickly.

    Id threw my track pads in on sat at wakefield, I then went for a 20 min run down the road and did this, Brakes performed as expected.

    1 After installing new disc rotors &/or brake pads, perform 8 to 10 slow-downs applying moderate pressure from approximately 50 60 KM/h without coming to a complete stop
    2 Make an additional 2 to 3 slow-downs, applying heavy pressure from approximately 60 70 KM/h without coming to a complete stop.
    3 Allow at least 15 minutes for brake system to cool down.

  5. #5
    Purist, whats that? Jason Broadhurst's Avatar
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    I would get weird deposits in your pads checked out man.
    Jason Broadhurst

    Someone once asked me if they could use my mower. I said "sure, so long as it doesn't leave my yard"

  6. #6
    Title pending
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    EBC greens used to be dreadful for this when used with DBA slotted
    Resins leech out of the pads and drop onto the rotor cause they aren't getting hot enough to burn off
    Stop being a pussy and get some temp in them
    Brembo pads have probably bed the rotor in by now... and probably good enough for the job anyway
    But if you still want to try the new pads... scuff em... then work them
    Location Perth Western Australia

  7. #7
    Registered User Sean951's Avatar
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    We had the same thing on one of our track cars. First time use of the winmax/circo pads, followed bed in to a tea and the car had an unbelievable shutter as you even breath on the pedal. threw the winmax as far as we could and installed project Mu no more problems. Upon saying this we also installed a set in a 944 turbo with stock brakes that just circulates burrows days and they worked perfectly for him. Same compound, new vs old rotors not sure why there was a difference.

  8. #8
    Registered User AlexinPerth's Avatar
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    Rub back the rotors as best you can with emery before bedding in as above.

  9. #9
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    Quote Originally Posted by AlexinPerth View Post
    Rub back the rotors as best you can with emery before bedding in as above.
    Why`s that? Give the new pads something to chew on, or what?
    Quote Originally Posted by Skompa View Post
    Yeah, bit too nice for me, I prefer my R32s with mountains of bog and LS engines

  10. #10
    Registered User AlexinPerth's Avatar
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    Remove the deposits from the previous pads & failed attempt at bedding in the new pads.

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