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Brakes not working whilst engine off?

Discussion in 'A3/S3 Forum (8L Chassis)' started by Andy_S3, Aug 5, 2009.

  1. Andy_S3
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    Andy_S3 Member VCDS Map User

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    [Aug 5, 2009]
    Have just noticed this earlier on. Is this always the case? I could have sworn I could move the car and use the brakes without the engine on - now it just rolls down my drive! :think: Also I just put the car in gear, took off the hand brake and let the clutch out (with the engine off obviously) and again it slowly started moving slowly down the bank of my driveway! Any ideas?
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  3. <tuffty/>
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    <tuffty/> Badger 5 Edition Staff Member Moderator

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    [Aug 5, 2009]
    Resurfacing your drive so its flat? using the missus as a wheel chock? Turning the engine on?

    or...

    The brake servo looses its pressure when the engine is turned off and pumping the brakes makes the pedal harder and you loose braking ability. Servos are supposed to hold pressure for a certain amount of time to allow you to pull up if the engine stalls at speed but will loose pressure on subsequent applications.

    In short, I am pretty sure its by design and all cars are the same... happy to be proven otherwise :)

    Putting into gear won't help too much if you are on a steepish slope either as the weight of the car will just turn the engine over.

    <tuffty/>
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  4. slim40
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    slim40 Member

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    [Aug 5, 2009]
    Yes, that's normal. Brakes are servo assisted, using the vacuum from the inlet manifold (or a pump on a diesel engine). With the engine off, they will work for maybe one or two presses, but when the remaining vacuum is used, that's it. They will still work, but you'll have to stand on them to get anything!
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  5. zeeeebo
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    zeeeebo Lifes one big laugh

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    [Aug 5, 2009]
    the brakes are power assisted! the car should roll but not if its in gear !! the handbrake will work when engine is off as its a cable but brakes wont! have you tried differnt gears other than 1 such as reverse and forth?
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  6. zeeeebo
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    zeeeebo Lifes one big laugh

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    [Aug 5, 2009]
    sorry didnt see 2 other ppl replied while i was typing
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  7. slim40
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    slim40 Member

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    [Aug 5, 2009]
    Ah yes, the handbrake should always work too!
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  8. Andy_S3
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    Andy_S3 Member VCDS Map User

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    [Aug 5, 2009]
    Thanks for that guys, has put my mind at ease a bit. have tried putting it in reverse and it wont budge now. So its all good! Thanks again
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