Rotors replaced twice in 2 years

My brakes grab at low speed when they have flash rust—that (plus the grindy sound) is exactly how I tell they need a nice neutral scrub.

-Chap

 

zackily what i was wondering.

 

You don't need to do this. The friction brakes already get used when the speed has become low. They will also be used at higher speeds with the harder you push the pedal.

This raises the question, is this your first hybrid? That grabbing you feel at low speeds could just be normal as the different feel between the regenerative and friction braking.

 

she makes it sound like the grabbing feeling begins prior to replacement work, not all the time.

 

Which might mean dry caliper pins? Who knows.

 

Either way, there should be the squeaking from the pad wear indicators if they are truly worn down.

 

Many Prius owners do need to do this, and it has been covered in posts here on PriusChat for many years. I learned about it right here on PriusChat when I bought my first Prius in 2008, and it was well-understood old news even then.

My brakes will be noisy and grabby after any short period of sitting in damp weather. Two or three simple stops in neutral will clean them off right away, back to perfect smooth, silent operation. Without shifting to neutral, the friction brakes do get phased in at low speeds, but only enough to make noise and feel grabby, not enough to correct the problem. A strong sudden brake application at high speed might do the trick, yes, but that's more jarring to the car, your passengers, and surrounding traffic than simply switching to neutral for your next two or three normal, coordinated stops.

Maybe the argument is the rotors would eventually get clean just through normal use of the brakes, without using this technique, but I'm not sure that's even necessarily true. I've never experimented with leaving them unfixed long enough to find out how long that takes. It certainly doesn't happen within the length of my commute. Plus, the rusty surface is rough and better at harboring moisture, so if you notice the problem developing and don't correct it right away, the amount of friction braking in normal operation may not keep up with the vicious cycle involved.

Probably the best argument for making sure PriusChat readers understand how to do this is the amount of money some of them report spending on repeated brake jobs when they don't. There is one thread at least on PC where an owner reported going to the dealer and authorizing a $900 charge, repeatedly, instead of shifting into neutral and stopping a couple times. That suggests the problem wasn't getting better by itself through normal use of the brakes, or at least not fast enough for the confidence of the owner.

-Chap

 

Surface rust on the rotors in a regular occurrence here on all cars. Never lead to any issues on our 2005 Prius.

Perhaps Toyota has switched to cheaper iron for them.

 

Happened often in my 2001, happens often in my 2010. 2005 must have been the year they got everything right. Or our driving and garaging situations are different, or something.

Sure, any car's rotors will surface rust up the same way. It's just that any conventional car will clean it up within the first couple of stops—same as a Prius will, if the Prius is in neutral for the first couple of stops.

-Chap

 

i don't think it leads to issues. it's noisy, and may cause some extra grabbiness until it's gone, i'm not sure.

my garage is very moist at times, and when it is, i need a bit more cleaning than just backing out of the driveway.
after 5 weeks away, i run it up to 40mph on a quiet road, hit neutral, and gently apply the brakes until it's gone.

 

I live in the moisture capitol of North America. Never "needed" to do the neutral braking trick. It always took care of itself, but I'm sure a stop or two in neutral would have cleared it up more quickly.

This is weird, though. It would be good to know exactly what the shop says is wrong and what proof they have. We just had my wife's car checked and the pads were at about 60%. It has 120k miles, 22k of which are ours.

 

Well, my 2012 C also has grabby brakes when it is damp outside. Once the brakes heat up, they do seem to work better (grab less), but never as good as on a dry day.

I thought that my rear drums were locking up, but the dealer told me that the front rotors needed to be resurfaced (turned). They looked like something had been sprayed on the braking surface. After being resurfaced, the brake system worked beautifully. But after a time, they symptoms reappeared. I just live with it, though a new set of rotors would probably cure it.

 

How often have you tried coming to a nice civilized stop, in neutral, two or three times in a row, just when you notice your brakes being grabby when it's damp?

I'm not saying it cures all ills, but what you're describing sounds exactly like what it cures.

-Chap