braking in reverse

I was thinking the update may fix it. would be nice to have some more reports from other owners.

 

I had this problem and started backing down the hill of my street in neutral to remedy it. My theory was the brakes had been worn in the direction of the forward tire rotation so that backing down would smooth out the "edge" that might have developed. Don't know whether that was the case, but after "shaving" off the "edge" that may have developed, the problem went away. Drive up to the top of a hill, put it in neutral, and let the car roll down the incline with the brake pedal depressed until the grabbing dissipates.

 

Not a bad theory but did you notice when it happened that your brake pedal sank to the floor without any (or little) back pressure? The second time it happened to me I knew it was going to happen because of the pedal feel.

 

I've had the reverse grabbing brake problem fairly often since new--now have about 3100 miles. Always happened backing out of the garage. No problem lately--kind of wonder if the way I brake when starting is the problem. At first I pressed the pedal down as far as it would go, then pushed power, kept foot on pedal into reverse and the grabbing happened when slowing down the reverse speed so I didn't hit my husband's truck. Now usually only touch the brake when starting. The other day I'd been sitting in the car for 10 minutes or so waiting for my husband. Was in pull in parking at the Dodge dealer next to a very tall one ton Dodge flatbed truck. Had to ease out into the parking lot where other cars were coming into the lot entrance--I was completely blind. Jerked like crazy! I shut it off then restarted and it was OK! Half an hour later I had the first real experience with the brake "hesitation" problem when I hit a pothole at a freeway off ramp stop sign. I had a previous incident, but now attribute it to ice--feel was totally different. Will get the brake update soon but I'm going to do some experimenting with the back up situation first. Didn't notice that the brake feel was different.

 

I've had the reverse grabbing brake problem consistently (as in 70% of the time). After the car warms up it's fine. Then if the car is turned off for 10 minutes it sometimes happens again. It's just annoying! Hoping the ABS software update will fix it!

 

On March 19 my Prius goes to its recall. I'll ask my dealer because it happened to me too but only when I start the car and must stop it almost immediatly (red light or a crossway).

 

A few people posted that they got the software update for the recall and it did not fix this issue. The two issues must be two completely unrelated brake problems.

 

My brand new(2 weeks) 2010 has exhibited this behavior frequently in reverse and once or twice at low speed going forward. When I took delivery the dealer indicated that all brake software updates for my vehicle had been performed . The problem is especially ridiculous in reverse on a slope as the car develops speed more readily and requires frequent application of the brakes.

 

happened to me today at 6900 miles. First time I've noticed it, so it's not one of those first 1200 mile breakin things (although I've had the other forward pothole thing since it was new). Was thinking of trading my basic III for a IV (wife would like the seats and navigation) and take advantage of the incentives, but now maybe I'll wait for the 2011 and see if some of these bugs get taken out first.

 

Yeah, and maybe even a PLUG! :rockon:

 

For those having this reverse break issue, I gave no detail in haste, sorry. It was just live several of the other posters. At ~7,000 miles without ever having this happen, I pulled up to the library, shut the car off. Kid runs in for some books. Turn on ACC mode to listen to the XM, kid comes out 10 minutes later, fire it up, shift to reverse, and do the bunny hop for all to see. Next time it happens I'll try the "lift the foot totally off", and if that doesn't do it, the "push Park, then back to reverse" method. This forum is great! Prius is a great car, but with a little more "R&D", it could be a safer one.

As for the oil change, I just received a new warranty/maintenance guide in the mail with the 10K mile 0W-20 information. If you look at the actual maintenance log area, they do recommend 5K changes only if driven in dirty/dusty conditions.

 

This reminds me of a problem I had with my Honda Odyssey. Whenever I backed it up for the first time in the day, tapping the brakes caused a loud "thunk." The cause of the problem was the design of the rear disc brakes. Because the brakes heat up tremendously, the brake pads need room for thermal expansion. A disc brake pad is a semi-circular piece of metal, which "floats" within the disc caliper. When it's cold, it's contracted, and when I'd back up and tap the brakes the first time, the brake pad would rotate backwards in the caliper and then stop, which made the thunk sound.

Once the car warmed up a slight bit, the pads expand and the problem can't occur. This is very similar to the conditions of the problem you're describing -- does this problem only occur when the Prius is cold? I don't think it's the exact same problem, because the symptom (brake grabbing) is different from a thunk sound, but the cause may be similar.

 

Glad I found this thread.. this exact thing happened to me a couple of weeks ago and it is on my brain every time I start the vehicle now... First time was in my driveway, don't remember how long I was in the car until my girlfriend got in.. but when I put it into reverse I got the same "stiff" feeling in the pedal and it felt like it wouldn't go down all the way... the car seemed to accelerate back faster than expected when I lifted my foot off the brake.... I lifted my foot and put the brake down and I stopped very quickly.

We then drove to the local market.. I sat in the car with the ACC mode on for about 5-8 minutes while she went in... when she came out I started the car, went to back up and the same thing happened.... this was VERY disconcerting in a crowded lot with lots of people walking in close proximity to the cars.... I believe I just hit the park button... then reapplied the brake (which now felt normal) and I haven't had the issue since....

I drove into some rural areas (dirt, yet graded) after leaving the grocery and a couple of days later I had a crazy squeeling in my car, I took it in and it ended up being a piece of wood in the brake pads or something... when the car went in I described both issues, and they were both noted on the work order... when they found the wood she called me to explain where the sound was coming from but said they could find nothing wrong with the brake and that the wood would not incite such an incident as described above...

I have been hoping that it was indeed the piece of wood somehow but did very much doubt it... thank goodness I found this thread as I had the EXACT same thing happen....

This is definitely something that needs to be addressed.. where does one file a complaint about an incident like this? we should all be doing it... NHTSA? Toyota?

 

Hey ya'll I just put in a formal complaint at the NHTSA... I think everyone should do this as it seems like a consistent complaint... the 'grabbing brakes' thing is annoying but the accelerating or hopping back with the stiff feeling could be straight up dangerous to a pedestrian..


there is the link to file a complaint.. if enough people do then maybe we can get some action happening on it...

Uh.. I tried to post the link but can't yet cause I have less than 5 posts.. but do a search for "nhtsa complaints"

and it is the first link... I will try to post a little later the actual link

 

Office of Defects Investigation (ODI), File A Safety Complaint

there is the link to file a complaint

 

Wow, so this wasn't just my imagination...I've noticed something similar on a car with just a little more than 1K miles.

 

This happens when you sit in the car for x amount of time before starting it. If you notice when you first enter the car you can hear a low buzzing humm, it is the brake pressurizing or something. If you sit too long in the car and then proceed to start and go, you are using only the friction brakes (some call it the grabby brakes). It is normal, and will also happen going forward. I figured this out within 2 weeks of having the car. Eventually you will figure out all the caveats and really start enjoying the high tech in this machine.

 

The reverse grabby brakes happened to me often. So now to prevent this from happening, I completely let off on the brakes when I start reversing...then right after, I put my foot down on the brakes. Seems to work.

I don't normally drive like this...I usually have my foot on the brake pendal and ease off when I reverse but I'll have to change the way I drive with this car.

Now if I can figure out a way to keep the grabby brakes from happening when I go forward. Happened just once recently...no idea what I can do to prevent it from happening again. Hopefully it wont happen again... hwell:

I still enjoy the car otherwise.

 

That wasn't true in my case. When this happened (about 7 times), it was after I parked for a significant time or was parked over night. It happened if I started going in reverse immediately after the ready light came on. It seems that if I let the car warm up a little longer, it may prevent it from occurring. Also, when it happens, I put the car in Park, wait a little and then it's OK.

 

No.
Even if that explanation was true, it is not "normal." It would be a flaw that needs correcting.
People don't want to have to worry about sitting an a car "too long."