I agree with yendog. File a complaint with NHTSA. I had the brake recall done, and this still happens to me when reversing.
After sitting in the car for a prolonged period of time, to avoid the grabby brakes, open and close the door, pat your head and stomach at the same time and then put into reverse. That should do it
The symptom is similar to the brake pressure building up beyond normal pressure. One wonders if the pressure relief valve gets stuck or the pressure monitoring device is not working and gets reset if Drive, Park or Neutral is selected. I do not know if there is a pressure relief valve to get stuck or brake pressure is only controlled by a monitoring device.
It is a recall from Toyota for 2010 Prius with certain VINs Toyota Recall Information ? 1998-2010 Sienna. (This link shows Sienna, but it IS regarding the braking on the 2010 Prius and has a place on the website page to enter your VIN to see if your car is on the recall list.) I received the recall notice in the mail, took my car to my dealer. 30 minutes later, I drove my car home. No problems since. The "hopping" has not returned, no discernible change in braking.
I got the the Prius recall fix done a few weeks ago, and it mostly fixed my braking in reverse jolting, but not completely. It's done it three times since then but not as severe. It's no longer a big issue for me.
This has happened to me also. I suspect that in reverse the hydraulics grab immediately, instead of going through the regen cycle the way the car does when going forward.
Mine has done this since day one. Very annoying. I go out of my way to try and diagnose it every time to no avail. When BARELY applying pressure to the brake pedal, as soon as it starts to grab and WITHOUT applying ANY more pressure to the pedal, the brakes clamp down completely on their own to a full stop. I am adding this to my laundry list of complaints when I go back to the dealer next time. The first time, they said the brakes were fine. I am not impressed with this car. I liked the Gen II much more.
just reading here. Interesting, happened to me just a couple days ago during heavy rain, backing out a park.
This is a potentially dangerous problem. I have experienced the brakes grabbing four times in the past six months -the most serious incident being last night. I was reversing out of a busy car park and found that the brakes were either fully on or fully off. The brake pedal was 'rock solid' and braking was violently aggressive.Releasing the brake in reverse had the effect of instantly moving backwards with no control over speed. On braking the effect was so violent that I thought I had hit another car or pedestrian. I live in the UK - and having studied this thread an convinced there is a major problem that needs a fix. It is definitely NOT driver error or driver induced. Does anyone out there have any further views - what is the relevant authority this should be reported to in the UK?
It is an attention getter for sure. The real question is it in fact a potentially dangerous problem. Be sure to report it to your dealership. I mentioned it to my tech writer when it happen to me (a couple of times). I would image writting to Toyota Corporate would help too.
There is a certain combination of events that causes this that involves sitting idle for some period of time before backing up. Has anyone found a way to consistently recreate it, knowing what steps to do and how long to wait, so you can show it to the dealer service department? Otherwise, it likely will not show the problem when they see the car and they will think you imagined it.
Mine is a Fleet Vehicle,and company policy is to park nose out, so I prob spend more time listening to those %%^$# beeps than most Prius drivers. Other than the aforementioned beeping, I haven't had any issues with reverse in mine...yet. (1,200 miles) Good Luck!
I experienced it a few times when the car was brand new (<1000 mi)--once even going forward. Never was able to consistently recreate it, but it seemed like it was more prone to happen if I started moving right after starting the car--almost like it needed to 'boot up' or something. Strange thing is, haven't experienced it in about 25K mi driving since. I also think it was more embarrassing than dangerous--it sure wasn't like the brakes weren't going to work! It always went away, too. I think it would be very hard to take it in and try to recreate it for a tech--better odds at buying a powerball ticket. ~T
The easiest workaround to get rid of it is, when the pedal gets hard, pump it a few times and then it goes back to normal. Just press the pedal hard a few times.
Happened again for first time in c8weeks. Reversing out of packing space - brakes lock up as soon as pressed - no real control, either on or off. Should not have to correct problem ourselves by unuasual breaking action - Toyota needs to recognise there is an issue here.
What works for me 100% of the time is lifting my foot completely off the brake momentarily (only once) then reapplying it. Instant cure, at least until Toyota comes out with a fix.
I have occasionally had the brakes grab and it seems to be related to the car being left overnight after it has been raining. I suspect that a film of rust forms on the brake surfaces that causes the uneven braking. Because of the Prius regenerative braking normal operation of the brakes does not use the friction brakes very much and so it probably tends to cause more of a problem than with conventional cars. It can usually be cured by using the brakes heavily a few times - you can try putting the car in neutral while stopping to ensure that the regenerative braking does not inhibit the friction braking. A Honda CRX I had also suffered to a smaller extent. Many front wheel drive cars don't get much of their braking from the rear wheels except when going in reverse. kevin
This low speed brake grabbing happens regularly on my Gen II both in forward and reverse. But this happens only in wet conditions. My thinking from experience is that brake grabbing I happens on all cars in wet conditions. For Prius brakes would take a lot longer to dry out because of regen braking. This would be more pronounced obviously in reverse as braking would be entirely frictional due to low speeds, and when backing out brakes haven't had time to dry out. Does this fit any of your experience? Was it in mostly in wet conditions?
Kevinwhite, Seems you have identical experience. I was out for some time and had not seen you response until page refresh.
4,000 miles now, and I use reverse several times a day---like every time I park in a non pull through space. I haven't seen this problem yet. Is it common? Serious? I'll keep watching and waiting....
