the problem with my brakes is that below 8mph the brakes seem to stick, then slide, stick and slide, about four times before i come to a stop, the car is 3 months old with about 2400 miles on it, i read the other posts and didn't get a clear answer. i have also noticed that when i slam on the brakes the car seems to "flex", like the back brakes are slow to grip. after i take my foot off the brake, the car relaxes and seems to flatten out. does anyone have an explanation? thanks
In normal driving the friction brakes are infrequently used. As a result, corrosion can build up on the front rotors and cause noise, and grabby brakes, below 8 mph One can either do a panic stop from about 30-40 mph in a safe location, or shift into N and ride the brakes a bit. That said, a Prius only 3 months old my first course of action would be booking a service appointment.
Have your front rotors machined, you have most likely got rust on the discs or have driven through water when the rotors were hot, I lean toward the first. Under light braking above 8mph you use regen braking rather than friction, when the system is working right and all the components are in good shape you will be hard pressed to feel the shift from regen to friction brakes. That's why you don't feel the pulsing above 8mph. It also means the front wheels do 100% of the braking at light pressure above 8mph. If the ABS is activated by a locked wheel or you brake hard the brakes switch to friction only. Stopping slowly saves a lot of fuel.
Hi psikot, Before you go to a dealer, try this. Others mentioned it, but did not fully explain... Go out and look at your brake rotors. These are the shiny metal disks behind the tires/wheels on the front of the car. If they have orange spots on them, you have brake surface rust. This happens on the Prius in corrosive conditions (warm wet weather, or near the sea shore, or melting weather during winter after salting), as the car uses electrical braking for most of the stoping. The shift from electrical braking to friction braking is at 7 mph. If the friction brakes are rusty, or wet, they wil act eratically. If that is all it is, there is an easy solution. Find a place without allot of traffic. Wait till there is no traffic behind you. Get the car up to between 40 and 50 mph, then as it coasts down thru 40 mph, push the shifter to N and hold it there until the gear indicator highlights N. Then Press the brake and hold it there all the way down below 20 mph. Then push the lever left and down into D, and when the indicator highlights D, release the lever and reaccellerate up to the speed limit. Repeat this 3 or 4 times, preferably with as little time as possible between the brakings. This gets the brake hot, which will cook water out of the grain of the metal, and it also grinds away the rust spots. Pull the car over in a parking lot. Now look at the brake rotors. The orange spots should be gone. If you have deep pits rotor(s) (very unlikely for a 3 mo old car) go see the dealer service. Concectric grooves are OK, no need to go to the dealer for that.
