Panic Braking Today

[1engineer]

I recommend that every new guy reading this thread PLEASE go to a long deserted parking lot and go about 40 mph and stomp the brakes really fast once or twice so you will know what to expect in a real life situation. I, like others, learned of this powerful feature when a deer ran out in front of me one night. You guys really need to do this. One word: Scary Powerful! (two words - my bad.)

 

[-JD-]

I recommend that every new guy reading this thread PLEASE go to a long deserted parking lot and go about 40 mph and stomp the brakes really fast once or twice so you will know what to expect in a real life situation. I, like others, learned of this powerful feature when a deer ran out in front of me one night. You guys really need to do this. One word: Scary Powerful! (two words - my bad.)

I agree. Its something you need to get used to as I found out today. Almost ran into the back of someone when there was more than enough room to stop just because I wasn't prepared for the brake system to react like that.

 

[Avalanche]

Very good info. Thanks to all for sharing this very important information with the rest of us.

 

[alc9020]

The first time it happened to me I almost got rear ended. I drive mostly in NYC so you can imagine the words I got from that incident. Now I drive with a little more space between me and the vehicle in front and I get cut off constantly but if you drive in NYC you can't expect to be in a hurry. So yeah the brakes work but maybe a bit too sensitive.

 

[eddiebx]

I recommend that every new guy reading this thread PLEASE go to a long deserted parking lot and go about 40 mph and stomp the brakes really fast once or twice so you will know what to expect in a real life situation. I, like others, learned of this powerful feature when a deer ran out in front of me one night. You guys really need to do this. One word: Scary Powerful! (two words - my bad.)

Does stomping and holding it down to mimic a panic stop really make this issue the most apparent? What I mean is if you are pretty much fully depressing the brakes anyway you might not feel it's full effects because you are already mentally anticipating it?

I might just be really numb, but I tried this a couple of times and while I definitely seemed to feel it, I also certainly wasn't blindsided by it. Most of you guys make it seem like it's pretty intense.

I believe JD had mentioned this earlier, but would this issue possibly be better displayed by accelerating up to speed and quickly taking a fast jab at the brake but not fully depressing it. For example, quickly switching from the gas to the brake pedal and rapidly slamming it down (but only 3/4 of the way down). This way, your mind is only thinking a quick (but light) deceleration, while the vehicle is doing it's thing; which might help you feel the full effects and prepare you better for what to anticipate in the future.

I plan to go play around with this more when I have another chance, but it's kind of hard to do on busy city streets and tiny city parking lots, lol.

 

[1engineer]

Does stomping and holding it down to mimic a panic stop really make this issue the most apparent? What I mean is if you are pretty much fully depressing the brakes anyway you might not feel it's full effects because you are already mentally anticipating it?

I might just be really numb, but I tried this a couple of times and while I definitely seemed to feel it, I also certainly wasn't blindsided by it. Most of you guys make it seem like it's pretty intense.

I believe JD had mentioned this earlier, but would this issue possibly be better displayed by accelerating up to speed and quickly taking a fast jab at the brake but not fully depressing it. For example, quickly switching from the gas to the brake pedal and rapidly slamming it down (but only 3/4 of the way down). This way, your mind is only thinking a quick (but light) deceleration, while the vehicle is doing it's thing; which might help you feel the full effects and prepare you better for what to anticipate in the future.

I plan to go play around with this more when I have another chance, but it's kind of hard to do on busy city streets and tiny city parking lots, lol.

Pretty sure its the speed of actuation Eddie. Slowly ddepressing the brake to full does not give you the same effect.

 

[eddiebx]

Pretty sure its the speed of actuation Eddie. Slowly ddepressing the brake to full does not give you the same effect.

Yea I think I know what you mean, when I slowly press it all the way down versus slamming quickly all the way down I definitely feel the brake assist kick in and "clamp down harder", so to speak (I know this is probably not even close to what's actually going on, but I have no intellectual way to describe it ).

But from reading some of the posts here it sounds like some people appear to be caught off guard not when actually trying to stop quickly in a panic stop situation, but when just partially depressing the brake quickly, if that makes sense?

ie. I want to get on the brake a bit to prepare to slow down, so I press it down half way (but I pressed it too fast to the half way point in a rush). I might be totally off, but it sounds like some are saying that just by pressing it too fast, the brake assist decides to do it's magic and slow the vehicle down rapidly (even though my only intention was to press half way).

 

[STLDAVE]

I just activated the 'panic braking' feature on my 4runner for the first time. Damn near launched me through the windshield. Was looking down for a minute and traffic stopped in front of me. The really annoying thing about it is that when the brakes suddenly go on full force your natural reaction is to let up on them, but then the panic braking thing disengages and you aren't pressing the brakes hard enough so you keep moving forward. Almost hit the car in front of me even though there was plenty of room because of this stupid braking 'feature'.

This caught me too a couple days ago for the first time. Almost passed the entrance to a business and hit the brakes hard enough to activate the "assist". As you said, my instinct was to release some of the pressure, which released the "assist" and I rolled past the entrance. I can see how you could end up rear-ending someone in this situation. (No jokes about rear-ending, OK? We're all adults here.)

 

[1000MPH]

Yea I think I know what you mean, when I slowly press it all the way down versus slamming quickly all the way down I definitely feel the brake assist kick in and "clamp down harder", so to speak (I know this is probably not even close to what's actually going on, but I have no intellectual way to describe it ).

But from reading some of the posts here it sounds like some people appear to be caught off guard not when actually trying to stop quickly in a panic stop situation, but when just partially depressing the brake quickly, if that makes sense?

ie. I want to get on the brake a bit to prepare to slow down, so I press it down half way (but I pressed it too fast to the half way point in a rush). I might be totally off, but it sounds like some are saying that just by pressing it too fast, the brake assist decides to do it's magic and slow the vehicle down rapidly (even though my only intention was to press half way).

Easiest way to activate it is a quick move from the gas to brake pedal. You don't need to be going very fast. Probably only 15-25 mph or so.
I wouldn't want to practice it at 40mph too much.

 

[Antman]

Easiest way to activate it is a quick move from the gas to brake pedal. You don't need to be going very fast. Probably only 15-25 mph or so.
I wouldn't want to practice it at 40mph too much.

True. Just move your foot very quickly from the gas to the brake pedal and you will be stoppin' like you threw an anchor out the back window.:fish2:

 

[eddiebx]

Easiest way to activate it is a quick move from the gas to brake pedal. You don't need to be going very fast. Probably only 15-25 mph or so.
I wouldn't want to practice it at 40mph too much.

But would you practice it at.......1000mph?

(I'm sorry, I couldn't resist , thanks for the tip though, I'll try it out!)

 

[WCVanHorne]

Anyone Experinece the Brake Assist when towing?

In less than a year of ownership I too have experience the brake assist probably 3 or 4 times. I have mixed feelings about it but it's likely overall a good feature, although I wish is would stop the boost if the pedal pressure was partly let up.

Anyhow I'm going to be towing a smaller (5'x12') utility trailer this summer. It will probably total 1500 lbs or less total weight. Because I'm cautious I got electric brakes and a Prodigy P2 controller as well. What I'm kind of curious about is the implications of the brake assist when towing. I'm sure having trailer brakes (particularly with an inertial/proportional controller) will help keep thing straight but I can imagine without them it could get really interesting in a brake assist situation. So anyone had brake assist kick in while towing something large or small?

 

[Jeremy556]

It will probably total 1500 lbs or less total weight. Because I'm cautious not stupid I got electric brakes and a Prodigy P2 controller as well.

I have not experienced it, but the prodigy will send the maximum voltage you have set to the trailer brakes if it does engage. Make sure your cargo is well secured :thumb3:

 

[mkp81]

Good to know all this. I wondered why it seemed like my ABS was kicking in so easily. My last 3 trucks (fords/Chevy) with drum rears rarely ever "locked up". I've had this panic brake deal kick in a few times already, and twice while towing my boat! Startles me every time lol, didn't feel I was braking that hard... Maybe I'm braking till quickly. Can't say I'm a fan, maybe I'll get use to it.

 

[Snooperstyle]

Ahhh...the brake assist. I have ranted about this in other threads, but for the new folks on here, just beware of it, and definitely go out to an empty street and try to see how it engages, because there is not a way to adjust it's sensitivity.

I had the fortunate experience of touring the Bosch plant here in Charleston, and I met the manager of the Bosch plant's anti-lock brake division. While that plant does not make the modules for our 4runners, they do make them for the Camrys and tons of other vehicles. He said that the sensitivity of the module's brake assist feature is determined prior to making the module and that it is all computer coded into the brains of the units, per manufacturer spec. I asked him if it would be possible to bypass the electronics of it, or do some other workaround, or somehow alter the sensitivity, and he said it is just not really possible without making an entire different electronic module to a different spec.

Our only option to adjust the sensitivity of these things is to become more cautious drivers. And that just irritates me because, while I do think it has made me more cautious as a driver and that is a great thing, I now I find myself being "scared" to hit the brakes too hard in unusual potentially dangerous stopping situations. No matter how cautious you drive, something can always startle a driver to cause him/her to quickly move from the gas pedal to the brake pedal, and if we could just adjust the system to be slightly less sensitive, then it would still save us fast pedal footers from accidents. As a caveat, I read somewhere that the system "learns" your driving habits, but I'm not sure that is true. The Bosch guy never said that it does that when I asked him. He just said it was set to manufacturer spec. And yes I know he didn't make the ones for the 4runner, but he says they all work basically the same way.

Hope that helps somebody...

 

[4runner10]

Yeah, it's a pretty impressive system. Prevented me from deer strikes a couple of times.

I never thought of "that a*$hole with a beater behind you on the cell phone" issue. There would definitely be a collision because the truck stops ridiculously fast!

However, as I recall pretty much as soon as you let off the brake the system disengages (or perhaps it occurs once it gets below a certain speed...).

 

[BlackWorksInc]

This is similar in the 4th gen's as well, the hardware didn't change all that much between the two, it is very disturbing to non-experienced drivers I'll admit. Part of the issue is that the 4th and 5th gen brakes are so oddly soft.

What I mean by this is that you can for the most part completely depress the brake pedal to the floor without feeling any significant change in feedback (in this case referring to how most brakes "firm" up as you depress further) and this in itself can be difficult to get used to. The brakes aren't really "spongy" they just have such a subtle change in feedback that you get used to just mashing on the pedal when braking versus say my step-dad's Lexus LandCruiser with very firm brakes.

The main reason behind this is actually the way the system is designed, it uses a much more powerful hydraulic booster to provide braking assistance and in doing so gives an extremely consistent pedal feel. The ABS solenoid pack, VSC/TRAC, and ABS module is bolted directly to the master cylinder and functions ideally similar to the Prius's disassociated braking. What I mean by this is that in emergency situations, or situations where the ABS/TRAC/VSC takes over, it can quite literally sever your input; in this case your foot pushing the piston in actually has little effect as the system seals those ports off to brake for you, or at least how it thinks you want to brake.

These powerful tools combined with a "learned" complacency with the static pedal feel can be very disorienting as the system will "bite" and bite hard when you need it. Its not like the older GM ABS units where their brakes were pointlessly spongey and difficult to stop with and when the ABS did kick in you vibrated for another 3 car lengths. Toyota built the system for the soccermoms and feebler people than they did for big burly man men like us!

Point being, its an amazingly well designed system (wish it were a little firmer in my opinion, I like that sports car firmness to the brakes) and it takes getting used to because it lulls you into a complacency with how effortlessly good the brakes work with such a consistently mellow braking feel... then BAM! When you need to stop, IT STOPS.

 

[mikeinmass]

The braking system on this truck (IMO) simply sucks, it's that simple. This has happened to me a few times in cases that absolutely not a panic event.

 

[Pails]

I think it is oversensitive on 4th gen as well. There have been more than a couple situations at low speed on a partly snow road where it lengthened braking distances by not locking up.

I've been researching why my TE has been sliding out on me in low speed turns on wet roads, at stop lights, lane changes, roundabouts....etc. The traction control, and brake assist nannies are WAY too sensitive. Contrary to popular belief, most of us know exactly what we're doing, I don't need my truck to "think" for me. Frankly I feel these systems are dangerous and unpredictable. It scares the crap out of my wife to the point she's now pining over our old Subaru. I'm starting to think she's right. Toyota had a bad run with safety a few years ago... They should just stick to pinning down floor mats. My rant.... Still love my TE though!

 

[pimpsta]

While we are on the subject of brakes, is there aftermarket upgrades for our 5th gen? I tried looking up Brembo, Stoptech, and Wilwood but They have nothing for the 5th gen.

IMO, stock brakes does it job stock but once you load it up with people and/or cargo, more "planning" is needed.