Brake Grinding
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Thread: Brake Grinding

  1. #1
    Fellow Frogger!
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    Default Brake Grinding

    On Saturday I was at home and a salesman offered to bring a car(German sedan, auto transmission) over for my dad to see. The salesman drove for about 20 minutes and explained the car, my dad said he had seen enough and the salesmen dropped us off. What my dad didn't like about the car was that every time the sales guy brought the car to a complete stop there was a rough jerk just before the full stop, every time the salesman would pull away from a stop light or stop sign you could hear the brakes grinding when he lifted his foot off the brake.

    That afternoon, the sales manager called and asked me why my dad wasn't interested, so I told him. Even though my dad had left, the sales manager sent the same car back around but with a different salesman. I went for the test drive and this time there was no jerkiness at a complete stop or grinding noise when he let his foot off the brake.

    What causes that jerkiness when most people have to bring a car to a full stop? And what is behind the grindy vibration when the driver eases up off the brake? Is it a flaw in the car that the second salesman knows how to compensate for? Each salesman made the car ride completely differnt.

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  2. #2
    Real cars have hydraulics DoubleChevron's Avatar
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    The first guy driving shouldn't be allowed to drive demonstrators.

    All cars will jerk badly when braking if you don't regulate the brakes. What you need to do in order to a smooth clean jerk free stop is regulate the brakes off just as your about to come to a halt.

    Next time your driving your car, brake hard to a stop, the car will jerk badly as you stop. Do it again, but this time just as the car is about to come to a complete halt, back off the brakes quite a bit and feel the difference (very noticable to passengers in the car. I always do it so passengers don't realise how heavily I brake at times).

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  3. #3
    Fellow Frogger!
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    Quote Originally Posted by DoubleChevron
    The first guy driving shouldn't be allowed to drive demonstrators.

    All cars will jerk badly when braking if you don't regulate the brakes. What you need to do in order to a smooth clean jerk free stop is regulate the brakes off just as your about to come to a halt.

    Next time your driving your car, brake hard to a stop, the car will jerk badly as you stop. Do it again, but this time just as the car is about to come to a complete halt, back off the brakes quite a bit and feel the difference (very noticable to passengers in the car. I always do it so passengers don't realise how heavily I brake at times).

    seeya,
    Shane L.

    Interesting DOUBLECHEVRON. I always thought it was normal for all cars to jerk a little, my dads feeling was that a car that expensive should stop smoothly.

    So DOUBLECHEVRON, you actually back off on the brakes a lot before a complete stop even in a heavy braking situation? Sounds like you're saying it was 100% the salesman's driving style.

  4. #4
    Sense Pug307's Avatar
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    I disagree - I blame the brakes. In some cars you just can't get away from that chirp or slight graunch - it's not the braking technique, it's the brakes.

    You often notice it after you've washed the car, the brakes aren't as smooth, usually graunching just at the moment you come to a halt. Modern Peugeots tend to do it a bit, but they're not famed for quiet brakes - a new pad composition appears to have fixed that up on the 206 though.

    The 307 does it, you can modulate your brakes but you'll get that chirp. Good luxury cars just don't do it - drove the Cross Country a few weeks back, didn't do it. Stomp like hell on the brakes, still beautifully smooth, quiet, no graunching at all, and you still stopped damn quickly.

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    Fellow Frogger! briz205's Avatar
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    Justin,

    DO you know this is a french forum not a swedish?? Your not the MD of volvo are you??

    Nick
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  6. #6
    nJm
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    It might have needed to have the front discs to be machined. I know our Magna's front brakes tend the chew up the discs quite a bit, and over time they start to make groaning/crunching type noises.
    Nick
    1983 Peugeot 505 GR


    "All of its cars from the 1.1 litre 205 through the ugly duckling 309 to the 2.2 litre 505 GTi had a rightness and a righteousness about them that turned every humdrum drive into a journey. Someone, I once wrote, in the bowels of Peugeot understands handling and how a chassis should feel." - Jeremy Clarkson

  7. #7
    Budding Architect ???? pugrambo's Avatar
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    or
    perhaps they were full of brake dust and they have cleaned them out before the other sales rep came back around with the car
    hence the lack of noise
    when they start getting gummed up with dust and road grime you can get the grinding type noise
    if they weren't shuddering then i'd say the discs were probably ok but just full of dust and grime

    spellng mistake

    i need a spell checker
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  8. #8
    Real cars have hydraulics DoubleChevron's Avatar
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    Hi Guys,

    By reading the comments it sounded like the driver was braking hard and coming to a stop with a 'thump'. This is particualy easy to do in softley sprung cars as the nose bobs back to it's normal height, and the cars bum drops back down all at once, after the cars come to a halt.

    Out of round brake rotor and contaminated brake pads should show as a shuddering while slowing, but not really a 'thump' as the car comes to a halt. Does this make sense

    seeya,
    Shane L.
    'Cit' homepage:
    Citroen Workshop
    Proper cars--
    '85 Series II CX2500 GTi Turbo I
    '63 ID19 http://www.aussiefrogs.com/forum/showthread.php?t=90325
    '72 DS21 ie 5spd pallas (last looked at ... about 15years ago)
    '78 GS1220 pallas
    '92 Range Rover Classic ... 5spd manual.

    Yay ... No Slugomatics


    Modern Junk:
    '07 Poogoe 407 HDi 6spd manual

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