Poll: Are Prius brakes a problem?

Bob,

I agree with everything you said above (except the part about a G2 Prius not having a lapse of regenerative breaking under 5 MPH - my wife and I both have felt this on occaision in our 2005 when we had it) as I've only had one experience in our new 2010 that I think is even close to what others are saying and for me it was a non-event. I'm going to keep trying to get the car to do this when I drive it (usually on weekends).

Mike

 

I'm coming in a little late to the discussion, but I don't think this is always the case. I practice extremely conservative driving, slowly coasting to long stops, and I have also experienced this sudden loss of braking while going over a bump. In my case, I was coming down a neighborhood steep hill (slowly) and doing my usual long slow braking for the intersection at the bottom. About 10 ft from the bottom of the hill and the intersection, there was a sudden sharp bump from a pothole, and abruptly my brakes weren't braking any more.

I was able to regain braking control by releasing the brake entirely and then slamming back down on the brakes again, but it was quite startling, and I'm just glad that I figured it out in time to miss sliding out into the intersection!

Take care,

--Sherri, otherwise happy 2010 Prius owner

 

Its happen to me 3 times only over the 5 months that I owned the car. 1 of them was quite scary on the highway.

To reproduce the problem, you have to travel at a constant speed not too slow and the brake have to be applied slightly and continuely (Slowly slowing down). There must be another car closely in front of you in order get the out of control feel. When you go over the potholes your car will lost the brake for a split second and you will feel like you dat forward and going to hit the car in front.

 

I will say after working in the auto repair industry for over 30 years that new technology is always un-nerving for consumers and technicians.
When ABS brakes were first introduced in the US, we had a constant stream of customers, who did not trust their dealer when they were told the brake pedal was supposed to push back at them and they shouldn't be able to lock up the brakes. We spent many hours of our time re-educating our customer to trust the technology. Since the late 70s, ABS feel has changed very little from one make to the next, even though the methods have varried greatly.
When I first began studying the Gen3 Prius, I was immediately impressed that someone was finally trying to do away with all the noise and pedal pulsing associated with an ABS system, but I also thought, "here we go again" on re-educating our customers. We have talked to many since the news media and our government has taken aim at Toyota and not one has failed to stop their car as expected.
I think the sensation of feeling like the car is not doing anything creates an immediate sense of panic, but is probably not causing the vehicle to stop any slower than it could normally.
With the old system, the solenoids would immediately give you feedback in the pedal that something was happening before the brake pads were engaged, but we have lost that feedback with the new design.
I think this is a good thing, but it will certainly take some getting used to.

I am also concerned greatly with the level of attacks being leveled at Toyota given the scale of their failures and their quick response. Are we trying to "level the playing field" a little?
GM had a big problem with brakes on their front wheel drive cars starting in 1980 that would cause the rear to lock up and send the car into a skid. This continued to be a problem for at least 10 years, even though there had been many accidents and deaths associated with the failures. During that time, the media and the government were pretty quiet about it.
I guess we lived in a different world then, but it is food for thought.

This is just my opinion and I am not trying to dismiss or disrespect anyone over this issue.

 

Has anyone tried replicating this scenario but not changing the pedal position when it happens. Both times that it's happened to me instaict takes over and I hit the pedal hard. It would be interesting to see what happens if the driver didn't do this, would the brakes still reapply???

 

Thanks, hybriddriveguy. I think your post provides a lot of needed perspective. Our world has become more polarized, and less tolerant to anything not perfect. Many of us now think that we live in a theme park where everything is clean, safe, and beautiful. My wife and I see this all of the time with sailing and rock climbing. There are a lot of people who think that the government should control the weather and make sure that rocks don't fall. Life just isn't that clean or easy. Hopefully we all do our best, and try to do the right thing, but at the end of the day a lot of s__t happens.

There are some bad apples; people and companies that try to cheat. They deserve to get smacked. However, for the rest, we need a little more tolerance and a whole lot less hysteria.

Tom

 

Hi Bob,

Yep, I realized after posting and then reading the entire thread that I'd jumped the gun a bit (as well as bringing back a mostly dead thread...sorry about that, all). What a first impression to make! Thanks for being understanding despite my newbieness. :redface:

I will have to see if the pothole/bump is still there; this happened months ago, and I really just chalked it up at the time to "interesting albeit spooky Prius quirk" and have just been watchful since then. It was only yesterday when I started reading about the investigation that I said "Oh wow, that sounds exactly like what happened to me!" and decided to go to PriusChat to see if others had seen it too. I didn't realize that it was such a polarizing topic!

Trust me, I'm not a Toyota or a Prius hater. I love my 2010! Makes our summer drive to North Carolina from snowy New England more fun again. I do wish that this investigation didn't hit at the same time as their other massive recalls, Toyota is going through a very hard time right now.

Take care,

--Sherri :focus:

 

When we first got our Prius, we were driving across the Astoria bridge, in the pouring rain, I was driving, and we were on the OEM tires.

I was going pretty fast, noticed I was getting really close to the T intersection (the stoplight was red)... I slammed on the brakes as I hit the painted white bars on the road. I experienced a combination of hydroplaning, slipping, and the anti-slip feature, all at the same time. It was freaky. I very quickly realized that the fault was MY OWN, for driving too fast for the conditions, and for hitting the brakes hard on those painted stripes.

After replacing those OEM POS tires, I've never had that sort of problem. I do, occasionally, notice the slip/anti-slip response when I'm starting/stopping on a railroad track or a painted white stripe, when either is wet. It's momentary, and doesn't bother me much anymore.

 

comment deleted

 

Yes, I have tried this when the lane was clear well ahead of me. The brakes did re-engage very quickly, well under a one second delay. Once re-engaged, they were not at the same stopping power as they were initially.

 

over at NASIOC.com and Legacygt.com the Bridgestone OEM re92's are known as "SUCKstones"


nobody really likes them for spirited driving.


for all around driving they are just adequate.


the "bean counters" are everywhere.

 

another spot to repro

I know Bwilson4web is collecting data points but I'm not sure where the best place to post them is now...

Here's another report of a place to trigger the braking anomaly on a 3rd gen from a former coworker. He asked me to post it for him. I have not verified whether I can repro it there on my 2nd gen, yet. (It's 13 miles from my apartment and it's not an area I normally go to at all.)

296th Ave NE and Carnation-Duvall Road, Carnation, WA - Google Maps

In his own words:

I clarified with him that he's coming down 296th Ave NE towards the highway.

From some of his posts at work, long ago, he said that the braking anamoly is repro on his former 1st gen but feels consideradbly worse on his 3rd gen. From his old post (and how he described the coming around a corner on a gravel road, washboard, downhill, etc.) it sounds like he's talking about the exact same road as above. I can clarify. He also later stated that he's owned many other ABS equipped Toyotas and that his non-Priuses don't exhibit this kind of feedback while braking down that road.

 

I had a 2007 gen ii for almost 3 years.
did not once have any issue with the brakes.

for 5 months now i have a 2010 gen iii,
experienced the loss of brakeing power once (about 2 months ago).
i was surprized and startled. Thankfully there was no one infront of me.
Did try to recreate the situation numerous times on the very same spot, with no avail.

 

Bob, I have one for you... A Gen II report!!

los feliz,ca - Google Maps
Traveling away from camera, rough spot in lower portin of pic, however with recent rains it has degraded further than it looks!

I have a Gen II 08, V and run 42-40 PSI front/rear so I feel a lot of the drive. After 17,000 mies I can tell blindfolded when I am in Regen, Warp Stealth, and Battery or ICE acceleration.
It was medium traffic, coming up to to a stop way ahead, plenty of cars in front of me. I was going 35-40 tops, and since I knew I was going to have to stop ahead, I backed off the gas and went into Warp Stealth for a bit, NO arrows at all,then Regen mode, I traveled like that a bit, then hit brakes lightly. I could feel the deceleration effect, then I hit the rough patch in the pic. I felt the car drop into what felt like Warp Stealth mode, niether acceleration, nor deceleration. The effects lasted pretty much like your accelerometer readings, a split second, right after the bump, the "Problem" occured, a half sec of "Coasting", then deceleration again.
I actually started laughing...
This is what all the fuss is about....
C'mon!!
I promptly went around the block, and repoduced the effect.
Feeling quite pleased with myself for not only noticing the "Effect" but actually reproducing it, I Goggle Mapped the spot for you, and here we are!!!
I will stop by the dealer tomorrow, and talk to my Service Rep, have him put my name on a list of trouble makers. AND MOVE ON!!

Hey, NICE JOB, and ATTABOY, for the accelerometer write up. Well pesented, and honestly as I was laughing, in my head I was flashing back to your graph...Pretty much spot on for the effect I felt!

I downloaded an App for my Droid that will do XYZ readings. I think I will go back and see if I can record the "Effect"
It may not be as sensitive as your unit however!! If it records, I will do a Save Screen and post the pic!!
Thanks for your posts, always a great read!!!

 

I've only had situations where the traction control will fly in right when I'm about to break, can be a bit scary.