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Thread: Ongoing Brake Issues

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    Not A DSM verified Feedback Score 3 (100%) Polygon's Avatar
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    Ongoing Brake Issues

    This is going to be a long story, but I'm at my wits end.

    It all started a while ago when I upgraded from the factory rotors and some Axxis Ultimate pads. I bought some race shopper rotors and some Hawk HPS pads. I also flushed the system with some ATE super blue fluid. After the change the brake torque just wasn't the same. I was incapable of engaging ABS or locking the tires with full pedal pressure. I bled the brakes again, and again, and again. There was no air in the system. There are no leaks. And the brakes worked better the hotter they got. The rotors came in bags, soaked in oil. I figured that I didn't clean them well enough and that I contaminated the pads.

    Flash forward to this weekend. I installed new rotors which are R1 Concepts slotted rotors. They are zinc plated. The front pads are Carbotech Bobcats in the front, and SP Performance in the rear. I installed SCE's caliper bolts as well. I went out to bed the brakes. I still can't get the ABS to engage or the tires to lock. I let the car sit for a few hours and still, they feel like the old brakes.

    So, what could be wrong?

    Master Cylinder
    Booster
    Prop Valve
    Last edited by Polygon; 10-04-2010 at 12:29 AM.

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    owner since 2004 Feedback Score 0 colt45 gto's Avatar
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    does the pedal feel spongy at all?

    with upgraded brakes (race brakes) they only start to work right when they are upto temprature.

    also most rotors come coated with ani-rust its like a grease and regardless if they feel greasy or not i always clean them off with brake cleaner or degreaser. did you clean yours?
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    One day....it will be on 4 wheels. supporter Feedback Score 2 (100%)
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    does the pedal literally go all the way to the floor?
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    Sounds like how my brakes were performing. I could push as hard as I possibly could on the pedal, and no lock-up on dry roads. I don't know what it was, but I'm in for answers. I had assumed it was the HPS pads, lol.
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    Not A DSM verified Feedback Score 3 (100%) Polygon's Avatar
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    Quote Originally Posted by colt45 gto View Post
    does the pedal feel spongy at all?

    with upgraded brakes (race brakes) they only start to work right when they are upto temprature.

    also most rotors come coated with ani-rust its like a grease and regardless if they feel greasy or not i always clean them off with brake cleaner or degreaser. did you clean yours?
    It doesn't feel very spongy. They aren't race brakes. The pads are just Carbotech Bobcats (front) and SP Performance (rear). Both of which are street compounds. The rotors are just OE replacements from R1 Concepts. Just street rotors. The rotors are zinc plated, there were no oils of any kind. R1 Concepts said these have an installation ready finish. I still used brake cleaner on them once they were on to get the crap from my hands off.

    Quote Originally Posted by MR2 View Post
    does the pedal literally go all the way to the floor?
    I don't know if it's literally all the way to the floor. All I know is I'm pushing on the pedal as hard as I can.

    Quote Originally Posted by DocWalt View Post
    Sounds like how my brakes were performing. I could push as hard as I possibly could on the pedal, and no lock-up on dry roads. I don't know what it was, but I'm in for answers. I had assumed it was the HPS pads, lol.
    The HPSs are what I just removed.

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    Does the fluid level ever go down?
    Have you checked your linkage to make sure it moves freely through the full motion?

    -If the prop valve was bad you would just get uneven pressure to the front or back causing either the fron or rear brakes to lock up before the others, it wont make the pedal lose pressure.
    -If the brske booster was bad, you would still be able to stop it would just be harder to push the pedal down.
    -If the master is bad it could cause you to lose pressure in the pedal if it was leaking internally.

    -Austin@STM

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    Not A DSM verified Feedback Score 3 (100%) Polygon's Avatar
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    Well, that's what I thought. I know it's unlikely for a prop valve to fail anyhow. And boosters don't go out very often. Now, I had thought the MC might be bypassing as I've read that flushing the fluid can cause the internal seals to fail if they were on the verge. The fluid level doesn't drop which is another reason I don't suspect an external leak.

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    owner since 2004 Feedback Score 0 colt45 gto's Avatar
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    does it feel like the brake booster is working? pump the pedal with motor off until it goes real hard, keep pressure on and start the car, the pedal should drop slightly.

    you could always try bleeding the brakes again (with motor running) to see if you get and air out? do you use speed bleeders or no? start at the passenger rear and work your way round, passenger rear, drivers rear, drivers front, passenger front.

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    I switched my car to a 1g DSM Master Cylinder because of the driver side intake manifold, so i have my stock one sitting on the shelf. It worked great when it was on the car, its only got 70k on it. Send me $10 to cover shipping and its yours if you want it to see if it fixes the problem.

    -Austin@STM

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    Not A DSM verified Feedback Score 3 (100%) Polygon's Avatar
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    Quote Originally Posted by colt45 gto View Post
    does it feel like the brake booster is working? pump the pedal with motor off until it goes real hard, keep pressure on and start the car, the pedal should drop slightly.

    you could always try bleeding the brakes again (with motor running) to see if you get and air out? do you use speed bleeders or no? start at the passenger rear and work your way round, passenger rear, drivers rear, drivers front, passenger front.
    Engine off, pedal is hard and stays hard. Start the car and the pedal drops slightly.

    I've always bled the brakes in a split diagonal pattern as suggested in the FSM, with the engine running. I'm thinking of bleeding it again, this time, letting a shop do it with a power bleeder just for shits and giggles. I don't use speed bleeders, I never have trusted them.

    Quote Originally Posted by Austin@STM View Post
    I switched my car to a 1g DSM Master Cylinder because of the driver side intake manifold, so i have my stock one sitting on the shelf. It worked great when it was on the car, its only got 70k on it. Send me $10 to cover shipping and its yours if you want it to see if it fixes the problem.

    -Austin@STM
    Is it from an AWD and is it ABS or non/ABS?
    Last edited by Polygon; 10-04-2010 at 01:47 PM.

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