What happens when you pull the electronic parking brake while driving?


#1

today, I pulled the electronic parking brake while i was driving. I just wanted to see what would happen. I thought nothing would happen because the car would know it was moving. It did seem like it tried to kick in, but it could not. It did make a loud grinding noise from the front of the car, which I think is the ABS. I am really just wondering what the mechanics are behind this loud sound and what really happens when you pull the electronic parking brake while driving?

Thanks


#2

Make/model/year of vehicle?


#3

Make model and year are critical. Engine size too, it that’s optional.
In this case, knowing whether it’s an automatic or a manual could be a factor too.
And how fast your were going.

But generally when you apply the parking brake it acts like an emergency brake and activates regardless of everything else. And, since it only stops the rear wheels, if the parking brake is powerful enough to stop the rear wheels while you’re moving, the ABS system detects a significant difference in the wheel speed between the front and the rear and activates. The horrible crunching sound is then made by the ABS solenoids pulsating the brakes on the wheels that are still spinning. The system works by rapidly opening and closing a valve that interferes with the hydraulic pressure to that(those) wheel(s).

The sound you heard could have even come from the rear brakes clamping onto the rear rotors (or pressing the rear shoes into the drums) while they’re still being driven by the powertrain. If it’s an automatic, you’d be momentarily straining the powertrain and the torque converter lockup clutch. If it’s a manual, you’ll be forcing the brakes to try to stop the engine from turning. Depending on the size of the engine, the power of the brakes, and the speed of the car, that could range from a scary annoyance to a really nasty powertrain jolt.


#4

Its new, automatic CVT, 2.5 liter engine, AWD. Subaru Outback


#5

I’m wondering if OP means by “electronic parking brake” they are referring to the emergency brake, possibly labeled “E Brake” on the handle? If so, that’s not an electronic operated brake. It probably works by cable actuation and applies brakes to the rear wheels only. TSM’s post above explains how the ABS would respond if you pulled on the EBrake hard enough to partially lock up the rear wheels. If you only pulled on it enough to slow down the car that shouldn’t happen as both the front and rear wheels would slow down the same amount.

It’s a good idea to learn how the car responds to the Ebrake while driving. I’ve had to use the Ebrake on at least one occasion, that time to assist the stop when my truck’s front brakes suddenly went limp.


#6

I thought I’d covered that possibility with my last paragraph, but the points are excellent ones and worth explaining more than once. Besides, if I wasn’t clear, than I didn’t convey what I meant to.

I try to consciously avoid using the term “emergency brake” in favor of “parking brake”. We’ve had lengthy debates on that issue. :smile: But you may be right, it might be labeled “E BRAKE”.


#7

People do you not remember who this OP is? They had several posts that may have been fiction. If they are who they say they are then this is a 16 year old who claimed someone loaned them a brand new vehicle.

And yes there are parking brakes that are electronically operated.


#8

A little Googling reveals Subie Outbacks can indeed be configured with electronic parking brakes.


#9

Volvo, you may want to give the OP the benefit of the doubt. I see nothing in the post that suggests he/she is making this up.


#10

SMB-I am going by the past posts the OP made and I was not the only one that had doubts about the OP.

The real question is if someone did loan the OP a new vehicle why are they abusing it?


#11

My 2014 Subaru Legacy has an electric parking brake. Its a push button to set the brake, you can hear the electric motor setting the brake. You can release it by pulling back on the back side of the switch and you hear the motor again.

But it also releases automatically when you put it in gear and hit the gas. I pushed the button while moving slowly once just to see what would happen and nothing happened. It is not an emergency brake, only a parking brake.


#12

The operation of the emergency brake is in the owners manual;

Emergency brake

NOTE
. While using the emergency brake,
the electronic parking brake indicator
light and the indicator light on the
parking brake switch illuminate and a
chirp sounds.
. While using the emergency brake, a
sound may be heard from the engine
compartment. This is the operating
sound of the brake that is activated by
the Vehicle Dynamics Control system,
and does not indicate a malfunction.

If the foot brake has a malfunction, you
can stop the vehicle by pulling the parking
brake switch continuously.
While applying the emergency brake, the
electronic parking brake indicator light and
the indicator light on the parking brake
switch illuminate and a chirp sounds.

There seems to be room on a message board with little activity like this one for another discussion, even if it is though of as not to be genuine.


#13

Nevada: what make/model is that quote taken from?


#14

I can tell you what owners manual it did NOT come from and that is the 2014 Legacy. There is no mention of emergency brake at all, and you do not pull the parking brake switch to set the parking brake, you push it.


#15

The information above was taken from the 2016 Subaru Outback owners manual.


#16

I found emergency brake use information on page 7-40 of the 2014 Subaru Legacy online owners manual;

! Emergency brake
CAUTION
Use the emergency brake only in
case of an emergency. If the emergency
brake is excessively used,
the brake parts will wear down
faster or the brake may not work
sufficiently due to rear wheel brake
overheating.
NOTE
While using the emergency brake, the
brake system warning light and the
indicator light on the parking brake
switch illuminate and a chirp sounds.

If the foot brake has a malfunction, you
can stop the vehicle by pressing the
parking brake switch continuously.
While applying the emergency brake, the
brake system warning light and the indicator
light on the parking brake switch
illuminate and a chirp sounds.


#17

That is not present on the 15 Forester, so it must be a 2016 innovation. Seems like a step backwards.


#18

“That is not present on the 15 Forester, so it must be a 2016 innovation. Seems like a step backwards.”

No, the feature is only offered on the more-expensive Legacy sedan and the Outback.
The electronic e-brake has been standard on those models since the clean-sheet redesign for the 2010 model year. I have a 2011 Outback, and although I was initially skeptical about this feature, I found that I do like it.


#19

I’ll bet it makes it harder to a bootleg turn…soon, with stability control and electronic parking brakes, we’ll have a generation that has never known the joy of hooning it up at low speeds on a dirt parling lot!


#20

I wonder what will happen if I stick my finger in that moving fan…