brake surge again!

Not to worry, one thing I know about intermittent problems is they will come back. If not today, another day.

Did I get the location and direction correct?

We need to quantify the road surface. This is a hypothesis, if the rock in the road material is exposed and came from a stream, polished smooth, these can work like a 'slip 'n slide'. It doesn't take much and suddenly the road surface itself presents a problem that brakes can not handle.

Bob Wilson

 

I've never experienced it with Pearl S though with Pearl it was "normal".

BTW, it's "brake and brakes" not break or breaks. Unless they're broken.

 

On my daily commute, there's a downhill road leading to a right turn. The turning lane has this small pothole that the right wheels will go over. As I approach the turn, I slow down. Once I hit the pothole, I get the 'surge'. 100% reproducible.

The first time it happened, it was a bit of surprise. This forum has helped me to understand why it happens. So now I keep my distance and just press harder on the brakes after I hit the pothole.

 

Is it correct to call it a surge? The car is not accelerating but only having a few microseconds of no brake force. I know the feeling as I have done it with pre-updated 2010 Prii. Never got to experience it with post-updated Prii so far.

Mike

 

The brakes in the 2012 will put me up against my seatbelts firmly unless I deliberately watch the HSI and lighten up my foot on the pedal. They seem way over aggressive to me. I try my best to not use the friction brakes as much as I can to make 'em last Seems many other Toyota's are setup with super aggressive brakes since the fiasco with the Prius a while back. My wife was complaining last week when we were in a rental RAV4. Even the Swagger has wicked aggressive brakes.

Mike

 

Thanks,

I couldn't see the bumps and dips in the Google 'street view' but I grateful when I can read a speed sign.

Any guess about the slope? The building on the right suggests it is pretty steep.

I also noticed some rubber on the painted yellow curb. I hope that wasn't your tire track!

Bob Wilson

 

Bondo, I've experienced it a few times, and it got better after the software update (can't recall when it was, prob 2011). I still get it once in awhile when I'm in an area that I'm not familiar with the road surface, and it sneaks up on me. Usually, I can steer away from the bumps just enough that it's OK, but when it does happen I still get that "oh geez" feeling and my heart beats a little harder & faster for a few moments.

The brakes also work wonders as others have stated if you have to emergency stop with them. Almost ate my steering wheel once, and I don't think it would have been all that tasty .

 

I was just researching the "surge" to explain the lurch that I get in certain conditions when braking, often on a bit of slope, and hit a bit of a hole or bump. I guess it's nice to see that it's a known issue, though disconcerting when it happens.

 

First, I believe that the Prius gen 3 are really experiencing these braking problems. We now have 10k miles on our Oct 2011 build date Hatch and have not experienced any of these reported brake problems. My wife and I drove German cars with Bosch ABS brakes for over 20 yrs and in all this time never experienced any of the brake problems reported here. I am very curious as to what the reasons for the problems are and hope in all your sincere efforts can find out what is wrong, but I BELIEVE SOMETHING IS NOT RIGHT here. If I experienced these problems with the brakes it would not be acceptable to me and I would either get rid of the Prius or go after Toyota for the truth and an acceptable repair and I don't care what anyone thinks about my response on this serious matter.

 

Intermittent problems like the braking of the ZVW30 can be especially vexing. It took nearly two months before I was able to replicate what others reported and quantify with an accelerometer. We had just figured it out when Toyota announced the software patch to the brake controller that mitigated the problem . . . at least I could no longer reproduce it.

The worst thing about one intermittent problem is it can mask a second one that has a lower frequency. That is why I continue to work with anyone reporting a braking problem to see if we can match the original problem conditions and/or find a way to replicate the new report. It is time consuming but I don't know of any other way.

Your money and it should be spent for products that make you happy. So I look at problems as a puzzle and weigh them against the alternatives. Sometimes you just 'live with it' but other times, like you, it goes back to the seller. It just depends.

Bob Wilson

 

I respect your diagnostic expertise. Toyota rattles me sometimes in the way they feed us their misleading propaganda.

 

Thanks - pet peeve of mine, too.

 

Another pet peeve of mine besides the use of the wrong word (break instead of brake) is the use of peddle instead of pedal. Peddle is a verb, not a noun (Peddle - Definition and More from the Free Merriam-Webster Dictionary).

 

This happens to me almost daily due to a bump on an exit ramp near my work. I don't get the ABS light (I never get the pulsation a on the break pedal though, I assumed that's because it's all fly-by-wire ) but it has nearly lead me to hit the car in front of me numerous times. I mean the breaking efficiency suddenly changes it's bound to lead to an accident.

 

Or maybe the car is telling you that you need to slow down and brake more gradually? Speed and poor driving habits lead to accidents 99.9% of the time, not the Prius TCS

 

Did you have the software update? I see it is a 2010.

Mike

 

Depending on how large the bump in the road is, if the tire loses contact with the road due to rebound even for a split second, the ABS will kick in giving you the feeling of surging forward. This can happen with any vehicle. Nothing wrong with the car.

 

Since this is a known event, you can easily compensate by hitting this exit at a lower speed, start braking sooner, and maybe even brake harder as you come to the bump. If you know how you car is going to react to the situation, you have multiple ways to eliminate or minimize the negative braking aspect of your car.