Electronic Parking Brakes

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After watching "Talking Cars With Consumer Reports episodes #129 & #130, they have a small segment on Electronic Parking Brakes/EPB(as compared to hand or foot lever P-brakes). Will these EPB's stop a vehicle in an emergency?

First: Is to understand that these systems are NOT Emergency Brakes, they're Parking Brakes.

Second: Is that the EPB will eventually stop a car(in an emergency situation) the same as in the standard lever type P-brake would, keeping in mind that it's only working the rear brake or the small P-brake/drum brake.

Third: What could happen if your car loses all power? Will the EPB still work?
Should the vehicle lose all electronic/electric/mechanical power, the regular brakes(stepping on the brake pedal) themselves should still work!

Fourth: This is mine!

a)What would happen if you've parked the car with the EPB ON, only to get into your car later and find that the battery has gone dead(for whatever reason)?

b)What will happen to the EPB that were ON?

c)Can you have the EPB released in order to have the car towed?

d)Yes we all know about Jump Starting a vehicle but, what is this option is not available e.g., to our children or spouse and we ourselves are not available to help?

Fifth/& onward: Add you own scenario!

I don't mind the idea of the EPB however, in the salt belt states such as NY where I live, this just gives a reason for the system to fail in time...expensively!

I like being able to modulate my P-brakes and prefer the hand lever type of P-brake although personally I don't use them much if at all except for NY State Inspection as it's required.

What say you?
Anyone care to jump aboard and chime in?
 
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But, lets say that you needed to use it in one of the situations/scenarios above?
I still think that there are questions about the EPB's that need to be answered by the MFGs or if they haven't looked into these scenarios further, maybe they need to do so.

Maybe the EPB needs to go away like the Electric Seat Belts of the early '90s. And the latest news about DCT/DSG automated manual trannys is that, due to customers lack of acceptance and dislikes of them, many manufacturers are considering eliminating them all together. Maybe CVT's too as they all seem to be nothing but headaches for the customers and the reliability is not where it needs to be considering these trannys(DCT/DSG & CVT) have been on the market over a decade now!

But, lets stick with the subject of the EPB for now!
 
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I use mine in my M6 regulary as I have in all my cars. Anytime I'm parked on a slope I use it and just one in a while to make sure things don't freeze up. Wisconsin kills metal and anyone who owned a GM W-body knows what frozen rear calipers cost.

There is no modulation...only on or off. I can still use it to swing the rear end around in the winter but I can't be Colin McRae and control the drift. It could be used to stop the car in an emergency if you lost hydraulics, but no power equals no parking brake. If you lose both in a crash I would assume you wouldn't be in any condition to control the vehicle at all.

When activated, a motor does the job that I would do. Once on, it can be disabled by putting my foot on the brake and pull the switch. Alternately, with the car in gear and seatbelt on giving it gas will automatically release it.

Power windows have electric motors that can be exposed to the elements and they don't seem to be going away. Since I put on 35k miles a year, I don't see this as my forever car anyway.
 
My wife's Audi has a stick and and an electronic parking brake. She and I always set the parking brakes since we drive sticks.
I much prefer the hand brake on my GTI.
 
Ive driven cars with these many times. Can't stand them. Not because they're electronic, but because they're slow (yes the two may be related). It strikes me that the application could be electronic, but the release should be by spring.

Thank goodness none of our cars have these things...
 
My 2012 Subaru Legacy had EPB. The little plastic motor assembly was not much bigger than a pack of cigs IIRC. There are instructions given in the OM in regards to manually releasing the EPB. I think you used a tool supplied with jack, etc to crank the EPB loose in the event of no electrical power. You accessed the motor/actuator from under the side of the car, then a short set of cables ran from the actuator to each rear rotor hat.

I don't think many of today's parking brakes are intended to have any real stopping power with the vehicle underway. I'm not sure that's even a design factor. I know just prior to doing a rear brake job on our 2016 Nissan Quest at ~45K miles, I stomped on the PB to wear some material away to allow for easier rotor removal (PB in the rotor hat). Not a whole lot of braking power at all, although it will hold the van tight once it's stopped.
 
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The wife's new Escape has one, I hate it for a couple reasons, but I only use it if parking on a hill. You cannot "partially engage" it for a slight incline, it is full on all the time which to me is overkill and stressing the components every time it is on (wife uses it all the time). You have no feedback verification that it is on other than a light, and when the brake becomes out of adjustment, how will you know...with a manual brake the effort to apply reduces as it becomes out of adjustment. Last, its electric and subject to problems, when was the last time you had a mechanical brake just fail?
 
Playing the "what if..." game and making up off-the-wall scenarios doesn't support an argument.

Total brake failure isn't a reasonable scenario, but since we're playing the "what if..." game, I'd probably say that if you have brake failure, it's likely due to lack of maintenance and if you've neglected your hydraulic brake system to the point of failure, there's no way your mechanical parking brake works.

If your battery goes dead? You jump start it yourself. No longer an issue. If your wife has the car and the battery's dead, she calls a tow truck and he jump starts it. No longer an issue. If it needs a tow, again, the tow truck driver can power up the vehicle and release the parking brake. You think to truck drivers don't deal with things like this on a daily basis? How do you get the fancy 8-speed transmission in your Ram truck into neutral to tow it if the vehicle is dead? That cool rotary knob doesn't work without electricity. The easy answer: Put a jump box on it!

There is one large, overriding, must-have requirement for an electric parking brake: adaptive cruise control, specifically full speed, stop-and-go adaptive cruise control that can completely stop the car in traffic and continue. The vehicle needs an automated way to hold the car at a stand-still. Typically, this is all done through ABS. If the car needs to slow or stop, it pressurizes the brake fluid with the ABS pump and cycles whatever valves in the ABS hydraulic unit to slow the car down. When the vehicle is finally stopped, the ABS hold vales are energized, which holds hydraulic pressure. For most scenarios, this is fine, but it is possible to overheat the solenoids. To prevent that, after a certain amount of time, the vehicle will apply the parking brake. Additionally, for safety purposes, it may apply the parking brake... like if someone were to open the door and get out of the car when adaptive cruise control has the vehicle stopped.

There are other reasons too. Packaging is a big one. A large lever or pedal takes up valuable interior space. A switch? Not so much. Some systems use a separate control module and cables, almost like a retrofit (this is how my 2011 Buick Regal was), but most modern systems are controlled by the ABS module and use an electric actuator integrated into the rear caliper (this is how my wife's 2018 Equinox is). That means no more cables to stretch or seize. Additionally, the system cycles the parking brake on its own periodically to ensure everything is working properly, which is way more than most drivers ever do.

And yes, if absolutely necessary, the parking brake can be manually released. It's not all that easy, you'd be much better off simply getting the vehicle powered up with a jump box or something, but provisions to release are there.

The other slick thing is if you drive a stick, like my Regal was. Stopped on a hill? Set the EPB. That will hold the car until you let the clutch out. When it senses torque, indicating the clutch is engaging, it'll release the electric parking brake. No roll-back on hills!

So, what have we learned:

EPB is required in a specific instance. This means automakers *must* equip certain vehicle with an EPB. At that point, scaling costs makes it very affordable for an automaker to equipped *all* vehicles with an EPB, since engineering costs have already been accounted for.

More interior room. Less packaging space required for pedals and levers. Less weight as well.

Less likely to fail and less maintenance. Modern systems use software in the ABS unit and a simple electric actuator at the caliper. No cables to seize, no complicated linkage at the caliper, no corrosion-prone drum-in-hat designs. Also, the system proactivly maintains itself to ensure proper function.

Enhanced hill-holding capabilities.

Made-up scenarios are worthless.
 
The parking brake on my 2003 4Runner with 4-wheel disc brakes can only slow down the vehicle if it's already at a full stop before pushing on the foot pedal (lol). No matter how it's adjusted it's next to worthless. It's as useful as a chrome muffler bearing or a Ford Focus transmission.

I like the parking brake on my 84 Civic. It's drum brakes in the real and it's activated with a floor mounted lever near the floor-mounted gearshift lever. That means that it's a parking brake and an emergency brake, too. What a clever idea that new car designers appear to have not figured out.
 
I don't really like the idea of crawling underneath a car to manually release a parking brake that might lead the car to roll over me while I'm under there. Yeah I could chock a wheel if I could find something to stick under there... heck, the spare tire, maybe, if I have to get it out to get at the tool underneath it in the trunk.

There is also something to a manual connection. I used the handbrake on my camry when I hit some black ice because the way the brake proportioning works, the front locks up way early when on a very low-friction surface. I don't think a switch gives the same feedback or response time. Getting computers involved in a back-up system worries me, much like the "power button" Toyota runaway fiasco of ten years back. IMO those cars should have had a simple toggle switch for "emergency stop" and I like my cables.
smile.gif
 
Having lived in New York State, I want to know how is the Electronic Parking Brake tested when you go in for annual Safety Inspection? With regular parking brake, they engage it, then with car in gear, inspectors check to if car moves when they give it gas. With my cars both having EPB, stepping on the gas in gear releases the EPB.
 
Originally Posted By: Rick in PA
Not fond of the concept. I want something mechanical in command. Too durn many gadgets in modern cars, but that's another subject.


I agree. Which is why we (I) chose the Lex.
No: EPB, touchscreen, turbo etc.
 
Originally Posted By: skyactiv
My wife's Audi has a stick and and an electronic parking brake. She and I always set the parking brakes since we drive sticks.
I much prefer the hand brake on my GTI.


+1 here.

Too bad the new GTI's use Electronic though. Bummer.


Jeff
 
Originally Posted By: Jeffs2006EvoIX
Originally Posted By: skyactiv
My wife's Audi has a stick and and an electronic parking brake. She and I always set the parking brakes since we drive sticks.
I much prefer the hand brake on my GTI.


+1 here.

Too bad the new GTI's use Electronic though. Bummer.


Jeff


The regular GTI's still use the regular handbrake (even the mild facelift 2018 MK7.5), but the R's have the electronic version.
 
Dumbest thing ever. Even dumber than those 1990s electric seatbelts that oems stuck on cause they didn't have an airbag solution.

I guess if you're driving a snoozefest of a vehicle, the kind that had a foot parking brake it's not so bad. But that many luxury carmakers are putting them in their sporty cars says lots about the market these days. Posers galore.
 
Mid 50s Mopars had a drum brake built onto the drive shaft for an E brake. It could lock the wheels. "hat E brakes" on the BMW were ridiculous. Best only to park with, or not at all. I was using the all new parking brakes in the Rat quite a bit during use around the grounds. With calipers, I guess it is too complicated to rig a mechanical linkage. Bug drum brakes were big considering the weight and power of a Bug. Had lotsa fun in the woods in a Bug with just the E brake.
 
I'm certainly not saying I like these EPBs, but my guess is all mechanical ones will go away like mechanical throttle control. Like said above, it's so much easier in terms of packaging and for integration into computer controls. Same reasons as E-throttle.

I might be mistaken, but IIRC with my 2012 Subaru Legacy, you could force the EPB on while in motion. You just had to hold the button in.
 
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In my '15 Cherokee manual (only car I have with EPB), there is a great deal of explanation on how to operate it normally and while in motion. It is waaaay more complicated than a pedal or a lever. Personally, I hate it. It also says the "solution" to a EPB being engaged and you loose all power is...make sure your tow unit is a flatbed with a wheel dolly. Nice...
 
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