Do you use parking brake?

Discussion in 'Prime Main Forum (2017-Current)' started by Michael Nielsen, Feb 11, 2017.

  1. Since2002

    Since2002 Senior Lurker

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    Many years ago I read that you should practice stopping with your parking/emergency brake at least once so that if you ever have to do it in an emergency you will have already done it. So I have done that at least once with every new car I get, somewhere safe like on a street with no other cars around I try it out. It also lets you know how much (or little) braking force you get so that you won't be surprised in a real situation.

    In the old days with the t-handle (do any cars still have those?) the trick was to pull the t-handle first and then keep pulling on it while you applied the emergency brake, this kept the brake from locking into position. It was a bit awkward because you had to lean down as you held onto the t-handle with your left hand while steering with your right hand. Cars with a center lever it's a lot easier because you can just keep your thumb pressing on the release button while you are pulling on the lever to brake. The hardest is cars that you release the parking brake with your foot, because when you are trying to use it to slow the car, as you press the brake it basically locks in that position, the only way to reduce braking force is to momentarily apply full brake. Although since the braking force is not that strong it's not that bad. But worth practicing ahead of time instead of trying it out for the first time during an actual emergency.

    By the way I read the same thing about ABS that you should practice coming to a hard stop using them. So I do that also (just don't have things loose in back when you do!) I have read that a high percentage of crashes the person didn't use ABS correctly, either they tried to pulse the brakes, or they were too timid and didn't press the pedal hard enough. You should practice stomping hard on the brakes and coming to a full stop, of course with no one around, so that you won't hesitate to do so if needed in an emergency.
     
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  2. ChapmanF

    ChapmanF Senior Member

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    I find Toyota's push-on/push-off ratchet pushes off with just a slight push from wherever you are; if you got it locked in position halfway, you only need a little nudge past halfway to release it. Also, once released, it will not re-engage until you have let it almost completely back up.

    So that leads to a technique you can practice (it works for me), where you just start off with a quick double-push; that disengages the ratchet, it stays disengaged as long as you don't completely release the pedal, leaving you free to modulate the braking as you like (er, as well as you can modulate a parking brake you're trying to use as a stopping device, anyway). The trick would be remembering to do that in a panic situation.

    Unless it's badly out of adjustment, don't be too sure it can't throw you into an oversteer loss of control.

    -Chap
     
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  3. Skylis A

    Skylis A Senior Member

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    So I've gotten into the habit of using the parking brake pedal.

    Now I have to get into the habit of remembering to release it before hitting the gas. (n)
     
  4. PriusNeckBeard

    PriusNeckBeard Active Member

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    Or, user error.

    It's weird, but on occasion, I've actually depressed the parking brake, but some how slightly re-prssed it at the bottom of foot travel (or something like that - am not sure exactly what's happened).

    The result was, the parking brake pedal came back up from its intended bottom-most point. I forget if it ended up three-quarters way down, or half. Maybe occasionally back near the top.

    Thus the parking brake ended up not fully engaged, and needed a do-over.

    I think it's happened once in the Prius, more times in my previous car.
     
  5. PriusNeckBeard

    PriusNeckBeard Active Member

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    Mine reminds me because the car can't move !

    It also could save the pawl if rear ended, no? Per other pchat threads.

    I push parking brake first, the the Off button. Pawl not leaned on, not under duress. Also no clunk ever, which is nice.
     
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  6. Lee Jay

    Lee Jay Senior Member

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    No need. Just stop the car with the regular brake pedal, then push off.
     
  7. Trollbait

    Trollbait It's a D&D thing

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    Just noticed teh Camry rolls more than the Sable when the door is shut while just using the parking pawl.
    There should be an angry red light on the dash if the parking brake is engaged.

    How is that physically possible? 70% of the work that allows a normal braking event is done by the front wheels. Rear brakes alone aren't going to stop the car as quickly. Heat will be an issue because it reduces the coefficient of friction between the pads/shoes between the rotor/drum. Drums will also experience mechanical fade as the heat causes them to expand and pull away from the shoes. On top of that, manual parking brakes don't have the benefit of a power system to increase the applied force. Which might make electronic parking brakes better for an emergency.
     
  8. Lee Jay

    Lee Jay Senior Member

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    A normal braking event is less than 1/10th the power of an emergency braking event. The front brakes might do 70% of the work during an emergency event, with 30% on the back. But 1/10th of that is only 10% and 10% is less than 30%.
     
  9. WilDavis

    WilDavis Senior Member

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    All this discussion of brakes, (hand-brakes as the parking-brakes are called on t'other side of T'Pond), reminds me of my friend Michael's Twin-Cam MGA which he used to rally in the mid 1960s, I was a mere teen in those days, but I used to pump gas at his Dad's service station for pocket money, and Mike used to let me ride with him as his navigator at the local club events. His MGA had a "racing hand-brake", which operated as follows, when it was pulled up to get it to engage, but to get it to stay "on" the button had to be pressed for the pawl to engage the ratchet, so anyone unfamiliar with the device would be struggling to release the brake not realizing that the button was only used to set the brake and not release it. (…effective anti-theft device?)
    Having a "racing (or quick-release) hand-brake" fitted it made it much easier to do "hand-brake turns" since you didn't have to fuss with the release button… …well, it fooled me the first time he let me move his car, I remember him giving me the keys, and I was so chuffed as I proudly strode over to his car, got in, started it, and then couldn't release the bloody hand-brake :oops: o_O (cue: howls of ribald laughter from gathered audience) ;)
     
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  10. PriusNeckBeard

    PriusNeckBeard Active Member

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    Chap -

    It's late... my brain is not on it's game...

    What does this mean, exactly, to do ? (and why/what situation?)

    "So that leads to a technique you can practice (it works for me), where you just start off with a quick double-push; that disengages the ratchet, it stays disengaged as long as you don't completely release the pedal, leaving you free to modulate the braking as you like (er, as well as you can modulate a parking brake you're trying to use as a stopping device, anyway). The trick would be remembering to do that in a panic situation."

    Thanks much,
    pnb
     
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  11. HPrimeAdvanced

    HPrimeAdvanced Senior Member

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    In case your regular brakes fail. Been there with a '57 Plymouth!! You use the mechanical, so-called emergency brake to stop.

    .
     
  12. PriusNeckBeard

    PriusNeckBeard Active Member

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    Whoa, so you..
    1. Pump down to engage emergency brake
    2. Immediately pump again to disengage it?
    then 3. float the pedal up and down to brake less or more??

    (do I have that right, in a prius?)
     
  13. HPrimeAdvanced

    HPrimeAdvanced Senior Member

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    Yup, that's the principle.

    .
     
  14. PriusNeckBeard

    PriusNeckBeard Active Member

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    Scary! Really. as Chap mentioned, control of the car seems concern.

    Soo...

    1. a IRL, this is in case the front brakes fail? And we're just trying to use rear brakes using the "emergency" brake ?
    b (because, as I understand it, the emergency brake on the Prius is just sustained computer application of the rear brake, isn't it?)...

    2. So...to practice this...just do it at low speeds and should be fine? Anything to watch for, other than accidentally not-double-pumping and slamming myself to a stop? (at a few miles an hour, the first time, don't worry).

    Thx
     
  15. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    I've got a recollection the brakes hydraulic lines are in diagonal pairs, so if a brake line failed, it might (for example) be front right and rear left brake.
     
  16. El Dobro

    El Dobro A Member

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    Yep, they've been plumbing the brakes that way for years.
     
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  17. Mendel Leisk

    Mendel Leisk 'Orrible Oracle

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    Thinking about that parking brake technique, avoiding the ratcheting mechanism locking, I'm pretty sure I wouldn't have the presence of mind to do that in an emergency.
     
  18. Trollbait

    Trollbait It's a D&D thing

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    Toyota uses the same parking brake system in other models too.

    That or the front left, front right, and rear brakes are on separate circuits.

    Even if you do manage it, it is easy to lock up the rear wheels using the parking brake.
     
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  19. Lee Jay

    Lee Jay Senior Member

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    Have you tried it? It's either hard or impossible on dry ground. I couldn't do it.

    I did use the parking brake for the first time off of my driveway yesterday. I had to park on the street on a hill that probably should have had stairs on it instead of a sidewalk. Here's what I did. I stopped on the hill with the service (regular) brake, applied the parking brake all the way to the floor, put the car in park, then released the service brake. The car rolled about a half inch or so and jerked to a stop - exactly what others above said they don't like about NOT using the parking brake. It did it anyway even with the parking brake.
     
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  20. Trollbait

    Trollbait It's a D&D thing

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    I have, with easier to modulate hand brakes, and it is possible to lock the wheels. Since amount of force applied is a factor in the wheels locking up, not getting lock up is a sign of the limit on the braking force being applied by the parking brake.

    I'd expect give when parked on a slope, but not on level pavement. We now have a Camry, but have had a Prius and Matrix. They have all had more give and roll in Park gear on level ground than another brand I have driven. It is probably fine, but the thought that the car's weight is wobbling on a part inside the transmission can give one pause. Using the parking brake all the time could very well just be placebo, but it does no harm.
     
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