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Thread: ABS attack

  1. #1
    Z8 Novice
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    ABS attack

    Hello Z8 forum, thanks for creating a nice community

    Here's my issue: i have a 2001 Z8 that has 73,000 KMS.. i've driven my car more than any other Z8 in Canada (us Vancouverites love to drive) and consequently run into problems that no other Z8 has met.

    The most recent is as follows: at slow speeds (under 15k, usually under 5) if i apply moderate to threshold brake occasionally the car attacks me. The ABS goes nutz and the steering wheel shakes violently. All this happens in a matter of seconds, then dissapears.

    Since it is a new issue, i've tried to get BMW to diagnose but they can't, so they've blamed it on tire choice (i have Michelin Pilot Sport A/S) and say the only way they can accept responsibility is if i change back to stock tires.... UGH

    SO.... any feedback? anyone else experienced this?

    thanks... clint

  2. #2
    Team Z8 jawz's Avatar
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    Apr 2005
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    Flylikeus,

    I haven't experienced this, but one possibility might be warped brake rotors. You could check by getting the car rolling at the speed you think it happens most, then put the car in neutral, then apply the brakes. I would try this several times varying the speed and amount of braking until you can repeat it. (You know how it is when you take a car in to the dealership and you can't duplicate the problem!) If you feel vibration/ through the body, brake pedal or you notice unusual steering wheel fluctuation, I would suspect the rotors are warped.

    I'm sure there could be other things, but this is an easy thing to check first.

  3. #3
    Z8 Novice
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    Arrow

    hi jawz, thanks for the tip

    i was pretty sure it wasn't the rotors... but i tested anyways just to be sure... couldn't find any problems at any speeds, but a real disgnostic would probably be best

    do you think a warped rotor would cause the dsc and abs to react so violently? i'm not talking about rotor vibration in the steering wheel, it feels like the whole car jumping, and the steering wheel shakes like i was running over a couple baseball bats.!

    anyone got any advice? REALLY don't want to go back to runflats just so the dealership can rule tire choice out.

    THANKS

  4. #4

    It isn't the tires, that's for sure......

    and if your dealer says anything about the MPS tires just let him know they are exactly the tires used by BMW at the Z8 Driving School here in the USA. They feel they are the best all round tire for the car, and are better than the runflats.

    The issue is most likely caused by a combination of things that is upsetting the ABS, which is then freaking out. I have experienced this on several cars on the very rough road by my home. It is a steep downhill with a stop sign at the bottom, and a terrible surface. I get all kinds of 'ABS panic attacks' in everything from my old Land Cruiser to my GT3, Prius, Z8 and even my new Cayenne. It's always worse in the wet too, and I can get all the cars to do it now I know how, even when they're brand new!

    Anyhow, how does this relate to your car? Well, 'ABS Panic' exists, regardless of what your dealer may say, so the question is what is causing it.

    1.) I'd suggest get the discs re-skimmed, or if they are too worn to reskim, replace them.

    2.) At that mileage it might be a combo of worn wheel bearings, control arm bushings, and the shock mounts, so have all those checked, or better yet replaced at this mileage.

    if that makes no difference then try.....

    3.) A complete alingment, try to find a race shop with Hunter equipment to do this, as it is a job that surprisingly few dealers do that well.

    4.) If all that doesn't cure it then it could be the rack and pinion issue discussed elsewhere here.

    A few of our cars have had the disc warping, the control arm and steering rack & pinion issues, please do let us know what cures it so we can keep the knowledge in the database here. Good luck with it!
    Andrew Macpherson

    Expert Z8 Inspections, with full support for both Z8 sale and purchases.

  5. #5
    2001/Titan/Red Z8Cookie's Avatar
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    May 2003
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    Thumbs up Love this forum!

    "and if your dealer says anything about the MPS tires just let him know they are exactly the tires used by BMW at the Z8 Driving School here in the USA. They feel they are the best all round tire for the car, and are better than the runflats."

    That is a billiant reply! well done.

    Where would we be without this forum.

    Colin.

  6. #6
    Z8 Novice
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    believe it or not, they're still blaming the tire choice, and refuse to pursue unless we purchase runflats... unfortunately BMW NA is not active here in Canada, the Canadian group is completely seperate.... still trying though... will update

  7. #7

    My first thought is they can't duplicate the issue....

    thus they keep throwing out an irrelevant and illogical solution to a problem they can't identify. Have you actually been in the car with a service rep/tech and have they been able to duplicate the issue? If not I would certainly try to make that happen.

    If they won't play ball I'd seriously suggest that you call the CEO of BMW Canada and talk directly to him. Be very polite, and keep it simple, but explain that these are the tires used by BMW NA for their Z8 Driver's program, and that you have spoken to them about the issue. None of the over 15 cars that had a different owner at the helm every weekend for the Z8 DE exhibited this reaction. Ask him if you can bring the car to HQ and have their best man look at it. I don't think this is an unreasonable request for an owner of the most expensive car they've made to date.

    However if you rode in the car with the service tech, and it doesn't happen then you have a bigger worry, as intermittent issues like this are much harder to track down. As I mentioned I can induce all of my cars into ABS panic of the steep rough surfaced hill that leads down from my house, so ABS does have limits, it can be 'confused', and this will never be fixable.
    Andrew Macpherson

    Expert Z8 Inspections, with full support for both Z8 sale and purchases.