2008 Prius DEFINITELY has a brake problem

I've not had any problems with my Prius. One thing I noticed back when I had a Nissan Murano, though, is that if you try to brake while going over bumps, you can easily lose control of that particular vehicle. A lot of what people describe about this Prius problems sounds like what I experienced with the Murano. Because of the Murano issues, I have a habit of not braking over bumps or railroad tracks. I let off the accelerator. Obviously, I've not had to come to a sudden stop in those situations. Is this the same type problem, or am I missing something when I'm reading the articles?

 

Hi All,

I have a theory why people feel they loose brakes, when test after test have showed this is not typical of the 2 nd Gen Prius.

Braking force is developed by the foot against the pedal.

Part of that force is the muscles in the leg. But a good part of it is the dynamic force of the weight of the calf on the pedal during decelleration. Or another way to say it, the momentum of the mass of the lower part of the leg is creating a force, simply because the car is decellerating.

Now hit a pot-hole, or loose pavement, and the car momentarily reduces its rate of decelleration to avoid sliding, and switches to friction/abs mode. People easily maintain the same muscle motive power, but the momentum brake pedal force can be drastically reduced. Creating an illusion of lost braking.

Also, the pedal force / braking power gain is different between the electric and friction brakes. The friction brakes will need more force if wet or rusty, too. That is, it takes more pedal force to get the same braking power in the friction brakes, typically.

If your going to brake hard on intermitantly loose pavement (usually not a good idea), then be prepared to replace the momentum force, with more muscle force, quickly, when the car switches to friction brakes. Do this, and keep the brakes from being rusty (Coast-down cleaning technique and/or full wheel covers) and you will not really have any more loss of braking than any other car when on rough surfaces.

As a side note, for people reading this who do not drive a Prius. The Prius electric brakes take very little force to develope ALLOT of braking power. I used to drive a Saturn SL2. When I took a drive in a Prius at a dealarship, my first stop I slamed the poor salesmen into the belt so hard, his head went whipping forward. It took allot more foot force to stop a SL2 than a Prius in electric mode. What happens in the Prius, is it goes back to that friction brake mode when it hits rough surfaces, and although the Prius pedal gain in friction mode is allot more than the SL2 (less force for the same braking power), its still significantly less than the pedal gain when the Prius is in electric braking.

 

I have the same problem with my 2008 Prius. I took it into the dealer for this within 60 days of owning the car and they said they had no idea what I was talking about. I called them back today in light of the recall mess, and was rudely dismissed... told "it's not on the list of recall models so there's nothing to discuss".

 

I have to chuckle at all the "problems" coming out of the woodwork after 8 years of almost flawless reliability documented by Consumers Reports for the Prius and other Toyotas. All of a sudden, everybody has problems. I wonder what that says about the state of the Society.

I just read an article in March's Car and Driver, where they thoroughly tested a Camry for its braking under high accelerative conditions. They found its braking distances as good or better than controls of other automakers they tested. They found no evidence of sudden acceleration and being unable to brake the car under hard acceleration.
They did say that Toyota doesn't use a throttle or baffle? to suppress the engine when it's under braking, like some (not all) auto makers do. That would make the braking data look even better. But clearly, it isn't necessary. There was a veiled criticism of Toyota for this--to be consistent with the rest of the media.

They said all of this started when some Calif. cop got killed in his rented or leased Lexus 350 when he allegedly said on his cell that the car was accelerating and he couldn't brake it. Somebody decided to make this a political football, because the honest car media can't find anything wrong with these cars--at least with the Camry--which was targeted. After all, it's the no.1 bestseller in the industry.

As for the floor mat issue in the Prius, mine has two floor anchors with the OE mats. They can't move.

My wife just bought a Honda Insight LX. The car comes with no floor mats, just a thin rubber one on the driver's side--unanchored. I see no evidence of anchor hooks on the floor for a regular mat, though Honda may use a bracket under the seat (like the Civic) which I haven't looked for yet.

The Prius floor mat "issue" is BS. Somebody has targeted Toyota. You can start with the Detroit car media and the Michigan pols, who are at the forefront of all this. The survival of the Detroit car industry is at stake here, and a part of me says I can't blame them.

There has never been a better time to buy a Toyota or Honda. Buy low, sell high.
That's partly why my wife bought an Insight. $3K cheaper right now with the current Honda incentive than the best internet price on a new Prius. About the price of a used 08 Prius.

 

I have the same braking problem with my 08. I never mentioned it because it doesn't happen "that" often. Hopefully it will keep happening when it doesn't make much of a difference and not when I am avoiding something serious like a person.

 

this whole ordeal is pretty 'crazy'. I haven't taken my car to the dealer yet..waiting on the 35k mark for oil/lube to have them see if mine is in the recall pool. Its an 07. I honeslty haven't even paid much attention to this whole ordeal. All i know is VSC can cause some scares on certain road surfaces. I made a post about a year ago when i first really ex pierced it. My tires are loosing tread..plan to get new rubber soon for better traction, which should help VSC scares. Alot of this braking issue is normal from what i gather when you transition from Regen to Friction. You get some odd sensations, like a slight lurch..especially at low speeds. This can i suppose be an issue on icey roads, etc.

I know the ABS works on this car fine. It saved my life 2 weeks ago. I was nearly Tboned. But the car stopped from 55 mph and i went about 15 feet into the intersection. I was distracted ( not texting LOL). I have also tested ABS in wet conditions on empty roads and it stops very well, even on my ratty OEM tires.

I do not know though. Still gonna take it in and see whats up. The only thing i got in the mail was the floormat warning recall dealo.

 

My '07 Touring, with 24K, (and new Nokians) experiences similar - especially when coming across a manhole cover. "hydroplaning" is a good way to describe the unnerving split second sensation. It did this prior to Nokians (I initially thought maybe it was the OEM tires). While car drives a lil'better in snow now w/Nokians, its still far from a "snow car" in my opinion. And still "skips" when braking across a slippery surface - especially when braking downhill.

Nearing in on 3 yrs so wonder if I should get the extended warranty
and live with this, trade it in for a 2010 (figuring the 2010 should be
the safest model Toyota sells), or trade it in for another brand. My '07 is my 1st Toyota.

Have to wonder why Toyota doesn't extend its recall to pre-2010
Prius since there are owners who have come forward with this issue.
Would appear that many do not experience this, so the dealers shouldn't be overrun. Maybe they don't have an explanation or solution to pre-2010 issue?

 

The only way to get Toyota to focus on Gen II braking issues is to file a report with NHTSA. Back at post #25 in this thread, I provided a link for filing a report. If the brake issue is important to you, file a report.

 

Actually, if there is a safety recall, we all have to get the problem fixed, or be held liable if the problem causes an accident.

The reason I wouldn't complain about this to Toyota is because I've driven a dozen cars and trucks with ABS and they all do the same thing (the Prius is my first Toyota). They still stop better than cars and trucks without them.

 

... and yet you continue to bomb over potholes & washboard areas that you regularly drive? ... or is it that you manage to pick a new pothole/washboard route ... yet each & every single day, they too have pothole/washboard roads? did you ever consider not driving so fast? I duno ... they say the Prius gets better mpg's that way ... so I hear.

Let's see ... with between 1 to 2 million prius ... if only 5% made threads about it, that be what ... a few 1,000 threads. Maybe you'd like to volunteer as a mod assistant, and strap on that task your self? With 10 or 20 merges a day I figure we'll see you some time next year.


EDIT:
OK, now i too note a brake problem. 90,000-ish miles, and the rotor pads hardly look worn. Something's definitely wrong. What's up with that?


.

 

I too have owned and driven a lot of cars and trucks w/ABS but never
experienced this sensation - especially when one can pinpoint "when" - slowing, braking downhill - and "what" - manhole cover - may cause. Also own a 1994 Ford Ranger and it stops on a dime regardless of road conditions. Same with Hondas & Nissans I've owned.

Filed a report with NHTSA couple months ago when noticed how many other pre-2010 owners were expressing similar (again, prior to all this, was told its probably caused by the OEM tires, but they only had 22K on them).

 

We had issues with inconsistent braking and traction control on our '08 and all of that went away when we got rid of the crappy tires and put some quality all season tires that were not made for MPGs. The MPGs dropped 1 MPG and that's it. That's a great price to pay to get rid of the issues that we were having.

 

I was wondering whether fitting tires with improved traction would have any impact on the traction loss and resulting brake drop-out. Since Toyota has seen fit to specify a particular tire for the Prius, it would seem that they can either change the tire specification and retrofit the new tires to all of the cars they have already sold, or develop a revised brake control system and fit that to the cars they have already sold. I wonder which remedy will cost them less?

 

I replaced the OEM Bridgestones (only 22K on them) with Nokians this Nov, and the sensation still occurs. So its not my tires.

Was recently told by another Prius owner that this isn't a braking problem, its a traction control problem. That the traction control is likely causing the regen braking to stop. I thought traction control was something that "helps" a driver to feel more safe. If this is indeed an issue with traction control that would go against the whole purpose of having it. Wouldn't it?

 

This depends on the traction control. On the Gen II Prius, the purpose of traction control is to keep the HSD from being damaged. Slipping tires can produce shock loads and high electrical transients. The high electrical transients are probably the biggest problem.

Without traction control to cut power, the Prius could easily blow out expensive electronics when losing traction, whether accelerating or braking.

The Gen III Prius has added selective braking to the traction control system. It now functions more in the sense that you expect, while it still maintains the primary function of protecting the HSD.

Tom

 

This is my story. I had a problem because I couldn't push/lock my 2008 Prius. It has 3800 miles on it. I'm 80YO and extremely conservative driver. I'm afraid of all the enthusiastic young folks today, so sure of themselves and their robotic horses. Turns out my Prius Pony was trying to be helpful. The service man asked me for my keys. I couldn't find them. I panicked. He said "Not to worry". I didn't realize it but my keys had dropped out of the unzipped pocket and he found them in the car.

I had removed the carpet myself and just placed it on the passengers carpet. He surprised me "Did you bring it in for recall?". No I hadn't. So they did a brake recall. Now I've got to get used to the display all over again because the readout of the electrical system is different. For instance, now my running lights do use up the battery. Maybe they always did and I just didn't know it.

I learned to be aware of running lights from Prius Newbie forum here.
Decided to look for 2008 Prius Recall and here I am.
The a/c also uses up the battery.

Oh yes, they re-installed my original floor mat. Now if I hadn't been careless with my pocketbook, I'd never have taken in my 2008 Prius even though they kept sending me email to do this. I thought, gee, anyone can certainly remove a floor mat.

Toyota is so honest. I'm going to pay more attention to them. I wrote software for 26 years (1967-93) and had to work 7x24 because my fellow employees played tricks on me. It started in 1967 with a couple of females. I'm female but 15 years older than everyone else so they thought me an old fool. Born 1929.

 

Always nice to hear from another engineer. I suspect the issue with your running lights is the fact that you are now paying attention. It's the same reason that your car feels like it runs better after an oil change. The Gen II recall was very simple and had nothing to do with software or electronics. All they do is remove all-weather floor mats, make sure your floor mat is secured, and carve away some pieces from your accelerator and the floor to make more clearance. It's all mechanical.

Tom

 

If you were REALLY that concerned, you would have sold the car already, no? :der:

Shockingly, my 08 has never done what you described.

-Brad

 

I'm not sure about "enthusiastic". Historically, the younger set do what they've always done with few exceptions...they live under the delusion of immortality, and make decisions without the benefit of experience. This is a bit of a "Catch 22" because some of them don't live long enough to gain the experience and make a better decision next time, and may unfortunately "take someone else with them" in the process...

The above process seems to endlessly repeat itself every generation. A relative few learn from other peoples experiences, which is why History repeats itself over and over again...

For the few who do take advice from we Oldsters (about 55 here), take good advice from a Pilots adage...

"There are old pilots and bold Pilots, but no old bold Pilots".

 

well said.