Brake problems????

[Hozz]

Need help information with brakes on my 2010 Prius V with the AT Package. I have a slanted driveway ( about 4-5 degrees) and if I drive up driveway and let the car sit for a few minutes and then back down with slight pressure on brakes they grab. Absolutely impossible to back out smoothly. What am I doing wrong and does anyone else have this problem?? Thanks in advance, Hozz

[goingreen23]

Originally Posted by Hozz

Need help information with brakes on my 2010 Prius V with the AT Package. I have a slanted driveway ( about 4-5 degrees) and if I drive up driveway and let the car sit for a few minutes and then back down with slight pressure on brakes they grab. Absolutely impossible to back out smoothly. What am I doing wrong and does anyone else have this problem?? Thanks in advance, Hozz

same thing happened to me one time as i was backing out our inclined driveway... this is my first prius, I think its just us getting used to using the brakes. (too sensitive for me)

[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.

[LRKingII]

It almost sounds like the hill holder function is kicking in.
Page 243 in main manual

[HTMLSpinnr]

I think the OP is describing something I responded to in another thread. The brakes are a tad grabby and make it a bit hard to get just a gradual creep out of the car for close quarter maneuvering. That being said, if you're pushing pretty hard, you will get the hill holder function (noted if you get the flashing traction icon w/ a beep).

[wvgasguy]

I wouldn't think the hill holder would activate if you're in reverse.

[donee]

Hi All,

This sounds like rusty brake issue. In the Prius, it rarely uses the friction brakes, and as a consequence they can get grabby when the rotors get a coating of rust on them.

Allot of Prius people will shift into neutral coming into a stop below 40 mph on level terrain. This forces the car to use the friction brakes, and cleans them up. Do this a few times and the braking action should smooth out. Its pretty much SOP with a Prius to do this after heavy rain/sloppy driving. I have added flush wheel covers, which reduces the incidence of rotor rusting, but such wheel covers are not good in a mountain driving area.

[Mike Dimmick]

Based on the demo of hill-start assist at our pre-launch event, on about a 1 in 4 hill, the car doesn't move at all (the car did roll back when hill-start assist wasn't used). I wouldn't describe that as 'grabby'.

If you brake relatively lightly - about 1mph/sec at 70mph, 2mph/sec at 30mph, 3mph/sec at 20mph - the car can perform your braking needs entirely through regeneration (and frictional losses). The friction brakes only get used starting at about 6mph, which is only 2.6 metres per second. One revolution of the wheels is a little under two metres, so it's unlikely that the discs complete much more than one revolution if you're continuing to slow to a stop. That's not really enough to clean off road debris and water, and smooth off the disc's surface.

[eglmainz]

I see the same thing occur at low speed maneuverings. Whether in D or R, if i am crawling along, it seems to me that (unlike in a traditional car, which has the engine pulling you along as you use the brakes), the engine/battery stops powering the car at low speeds, and then the brakes feel very grabby. This is especially noticeable to me when I am stopped, and then trying to reverse into a parking spot. When I try to inch back the last few feet. At that point, the car seems to either stop, or want to lurch forward more than I am ready for. As I gently apply the brakes, the car is no longer propelled, so it then comes to jerky stop, instead of being able to smoothly inch back.

This does not seem to happen in any other circumstance other than when I am just trying to move 1 foot forward, like at a light, or backing up. When I drive, and use the brakes, all is good. They look clean, so I am thinking that the 'rust and debris' comments here have nothing to do with this, but instead it is a finicky brake pedal in the Gen 3 at low speed?

[HTMLSpinnr]

eglmainz, I'm inclined to agree, however will give the pads/rotors time to break in before I make a final judgement.

And for the sake of argument, hill hold assist (press prake down hard for 2 sec, observe traction control light and audible beep - car holds brakes until you press accelerator) does function in Reverse as well as Drive.