Brake problems????

[wvgasguy]

Originally Posted by HTMLSpinnr

I've purposedly paid attention braking over bumps, haven't had regen or ABS cut out yet, though one morning, I did notice on a relatively empty battery after hard acceleration to get into traffic, I had almost no regen effect on braking after a light change and had to press harder than usual to get enough friction braking to compensate. Wondering if the battery temp was deemed too high to allow charge until it cooled...

Either way, I didn't feel unsafe, just that it was abnormal.

I've experienced this before myself, though just consider this as something to expect and not follow too close or brake adequately in time. I've noticed it on my Prius yesterday and a couple of times on the TCH. When approaching a "T" intersection near my home they have rumble strips fairly close to the intersection. When applying the brakes there as I come to a stop (approx 10 mph) I did get a sensation that the car freewheeled just briefly. It is a little unnerving the first time. However I don't believe it affected my stopping distances by "feet" as some say they have experienced.

It's about the same but opposite sensation that I had in 2007 when I pulled out infront of traffic with a new hybrid car that had no engine running. People talked about the the non-responsiveness of the system scaring them but in reality the electric motor was applying the torque to get them moving while the ICE was kicking in. It felt scary but I don't believe any acceleration was delayed because of the system's funtion.

[Martin37]

Originally Posted by khoglan67

I had this problem this happen this morning. I put it back in park, pumped the brakes about 5 times, put it in drive and the brakes didn't grab anymore.

Haven't tried this - pumping brakes while in park - yet but I experienced OP's way too sensative braking just backing out of a slightly down hill parking space. Kind of felt (looked?) like comedy scene of brand new driver applying for first license at the department of motor vehicles..... Certainly not the results of rust/dirt, nor lack of braking in vehicle - 2300+ miles on Prius at the time.

[yardman 49]

I've often driven Ford Crown Vics/Marquis for work rental cars. They have a similar unnerving ABS behavior. Really badly startled me the first couple of times I hit a bump while stopping on a particular stretch of road that I would take.

As others described, it either felt like the car was accelerating or that the brakes weren't working. The effect was worse than anything I've yet experienced on my G2 Prius. I probably just haven't encountered the right set of circimstances, though.

All that being said, the G3 is a brand new model. There could be some slight differences in braking when compared to the G2s. For instance, my U.S. G2 has drum brakes in the back (which I actually prefer).

Best wishes,
Frank

[RobertMBecker]

Originally Posted by FlipStylee270

Has anyone experienced this type of brake problem?...

Theres plenty of pot-holes here in NYC, when I am braking on a slight downhill and run over some minor bumps, the car feels like it accelerates or someone rear-ended. I dont get any whiplash, but a sudden forward jerk when you are expecting to slow down.. Is this a common CVT transmission behavior when your are rapidly deccelerating?

If it this was like a manual transmission, it would feel like the hard clutch engagement during up-shifting at high RPMs. A little scary if the front vehicle is too close to you and you need that braking power with no "hiccups".

I've noticed the same EXACT thing for me here in New York City and just sent an email to my dealer about it. Hitting potholes or bumps seems to trigger it. Have you gotten to the bottom of this yet?

[qbee42]

Originally Posted by RobertMBecker

I've noticed the same EXACT thing for me here in New York City and just sent an email to my dealer about it. Hitting potholes or bumps seems to trigger it. Have you gotten to the bottom of this yet?

Yes we have gotten to the bottom of this. Did you read the rest of this thread? I won't retype all the details again, but in short the Prius normally uses regenerative braking, which brakes only with the front wheels. Hitting a potholes or bumps can cause a loss of traction, which causes a fast transition to normal friction brakes. It is the loss of traction and transition to friction brakes that you feel. This is normal. In a panic stop this is not an issue, as regenerative braking is not used.

Tom

[RobertMBecker]

As I have a stated in other similiar threads, debating the issue, trying to explain the WHY, or questioning how one is driving does not solve the problem--and it IS a problem. The bottom line is that if the car is not stopping when it should (which it is not), the safety of passengers and pedestrians is in jeopardy.

I have written certified letters to Customer Experience and the President of Toyota and have spoken to Technical Field Specialists and customer service reps and Toyota Executive Analysts. They all acknowledge that the braking issue occurs, but state that the car is operating "as designed." For me, this was unnacceptable, so my next step was to submit a report to the National Highway Traffic Safety Administration. About 50% of the current NHTSA reports on the 2010 Prius are in regards to this issue.

[qbee42]

Originally Posted by RobertMBecker

As I have a stated in other similiar threads, debating the issue, trying to explain the WHY, or questioning how one is driving does not solve the problem--and it IS a problem. The bottom line is that if the car is not stopping when it should (which it is not), the safety of passengers and pedestrians is in jeopardy.
<snip>

Most of us do not see this as a problem, nor do we find that the car is not stopping properly. The only stopping problem I've ever had with my 2006 came from the crappy OEM Goodyear Integrity tires. Perhaps yours is different than most.

Tom