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No. 6
Jun 30, 2002



Apologies if this has been posted before.

I'm trying to get down to the true intention of the parking brake (aka, E-brake, aka emergency brake, etc).

I'm guessing most folks first learns that they should use this if there's a hydraulic failure in the regular brake system. While that's certainly true, is that what engineers and car companies intend? I cannot find any official documentation on using the parking brake during emergencies. Furthermore, any references I find always refer to it as a parking brake.

The Wiki page is a nightmare. Sources cited are either auto-blog posts or real publications which do NOT mention any intentional emergency usage for parking brakes. I'd love to see documentation from a manufacturer which talks about the parking brake as a backup.

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ryanrs
Jul 12, 2011



The parking brake is for when you're parked. Lots of cars have an ratcheting pedal or an electronic doodad instead of a lever. These are definitely not intended to be used while the vehicle is in motion.

Your normal brakes have two hydraulic circuits, so if there's a failure they should still work to stop the car.

KYOON GRIFFEY JR
Apr 12, 2010




i'm truly fascinated by the genesis of this question

I'll check the manual of the E39 when I have to move it this afternoon

No. 6
Jun 30, 2002



ryanrs posted:

The parking brake is for when you're parked. Lots of cars have an ratcheting pedal or an electronic doodad instead of a lever. These are definitely not intended to be used while the vehicle is in motion.

This is exactly my thought and why I'm trying to find if there's ever a precedent for using the term "emergency brake."

Here's a bunch of Wikipedia info that, as far as I can tell, is just made up.

quote:

In vehicles with automatic transmissions, the parking brake was originally intended for emergency stopping (for instance, if the foot brake completely failed due to a loss of hydraulic pressure or other malfunction).[3] As safety regulations became more stringent in the 1980s, and modern brake systems became more reliable (using dual-circuit hydraulics and low-brake-fluid sensors),[4] the likelihood of brake failure reduced; in most cases this failure might be indicated through a brake warning light appearing on the dashboard.[5][6] In the event of brake failure, the parking brake lever should be slowly engaged to prevent locking up the wheels and reduce speed.[7]

Non of those citations actually state that the parking brake is ever designed or intended for emergencies. Some resources describe how it could be used in such an event, but that's never been described as an official function (and for good reason).

No. 6 fucked around with this message at 19:02 on Jun 17, 2021

tuna
Jul 17, 2003



It's actually a hand brake.
Well the non poo poo foot pedal ones anyway.

No. 6
Jun 30, 2002



Or those weird turn handle ones, like you find in old trucks or Cessnas.

Elephanthead
Sep 11, 2008




Toilet Rascal

The weird button one on the leaf that locks the whole system down and you need a level 6 tech if you lose the key fob.

KYOON GRIFFEY JR
Apr 12, 2010




Here's the copy from the E39 manual. It's actually kind of interesting.

"The parking brake is primarily designed to prevent the vehicle form rolling while parked. It operates against the rear wheels.

"If, in exceptional circumstances, it should be necessary to engage the parking brake while the vehicle is in motion, do not pull it with excessive pressure."

So they're never going to say explicitly "this is intended for emergency use" but they clearly know that it will likely be used n "exceptional circumstances."

No. 6
Jun 30, 2002



And I think this is the most sensible description. Thanks for posting.

Elephanthead
Sep 11, 2008




Toilet Rascal

tuna posted:

It's actually a hand brake.
Well the non poo poo foot pedal ones anyway.

And it is for doing sick turns to impress potential lovers not parking.

Krakkles
May 5, 2003
WITNESSED





My auto shop teacher many years ago said:

"It's called an emergency brake because if you try to use it while the car is moving, it will cause an emergency."

That being said, to Kyoon's (BMW manual) point: If you are really, really careful and really, really sure of what you're doing, you can slow a car down with it, but you need to be really, really careful.

Having done it, I'd say it's most akin to operating an old, manual mill - you pull the lever with the release engaged up until you get the pressure right, and you're varying the pressure according to feel. You could probably achieve the same with a foot-operated brake if it has a separate operable release - not the kind that ratchet into and out of position - but I don't think it'd be fun to try on my car under pressure.

Elephanthead posted:

And it is for doing sick turns to impress potential lovers not parking.
After years of trying, I can say with some authority that this is not an effective means of impressing potential lovers.

CAT INTERCEPTOR
Nov 9, 2004

SOOB UWU?!?!


Krakkles posted:

After years of trying, I can say with some authority that this is not an effective means of impressing potential lovers.

I would disagree - It has always been effective.

Elmnt80
Dec 30, 2012

There is a certain joy in a freshly laundered jock strap





CAT INTERCEPTOR posted:

I would disagree - It has always been effective.

Maybe it only works on canadians? Can ABAI confirm?

Kazinsal
Dec 13, 2011



Can confirm, if a lady drifted into a parking spot with me in the passenger seat my next stop would probably be to go get a ring.

Raluek
Nov 3, 2006

WUT.


Krakkles posted:

You could probably achieve the same with a foot-operated brake if it has a separate operable release - not the kind that ratchet into and out of position - but I don't think it'd be fun to try on my car under pressure.

ive done this. it works but is sorta sketchy

i like your quote, but it did not cause an emergency

slidebite
Nov 6, 2005

Good egg
:colbert:


Elmnt80 posted:

Maybe it only works on canadians? Can ABAI confirm?
Did an e-brake drift and seat passenger seat was wet afterwards. Take from that as you will.

22 Eargesplitten
Oct 10, 2010





:piss:

Krakkles
May 5, 2003
WITNESSED





CAT INTERCEPTOR posted:

I would disagree - It has always been effective.
Sorry, I should clarify - potential female lovers.

Krakkles fucked around with this message at 18:35 on Jun 19, 2021

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madeintaipei
Jul 13, 2012



Krakkles posted:


You could probably achieve the same with a foot-operated brake if it has a separate operable release - not the kind that ratchet into and out of position - but I don't think it'd be fun to try on my car under pressure.


No, thank you. I'd like to save as many teeth as possible.

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