I have a new Toyota Corolla. I have had problems with the brakes. If I brake when I go over a bumpy surface or am turning up a slight rise, I feel the car shudder underneath the brake pedal. It feels like the vibration you get if you ride too far to the right off a highway into the service lane. I took it to the dealer and of course couldn’t reproduce the situation. I’ve asked some other new Corolla owners and they have had the same problem. Any ideas?
It’s the ABS doing that. ABS works by interfering with the hydraulics on any one wheel that stops turning at the same speed as the others when the brakes are applied. It thinks it’s locked and sliding. When you go over a washboard road and apply the brakes, the speed of the wheels varies wildly as it skips over the ripples with the friction of the pads applied. The ABS doesn;t know how to interpret this, so it keeps applying its magic, thinking each of the wheels keeps losing traction. It’s one of the inherant weaknesses of the system.
Mountainbike is correct. These driving conditions can cause enough of a variance in wheel speed to cause the ABS to engage and try to keep the car on its intended course. I have a Grand Cherokee that does that under the same conditions. Do not despair, you are not the first person to be confused by the ABS system. I had a customer once who kept bringing his truck in to the shop every time the winter weather got bad, saying he was experiencing brake problems and wanting it corrected since I replaced his brakes a few months prior. I could never find a problem and kept asking him if it could be normal ABS activity. He insisted it was not, but around the third time he came back, I put him in the passenger seat for a test drive, took his truck into a snowy/icy parking lot and slammed on the brakes. He said that was the noise and feeling he was getting, and I had to explain why that was normal and acceptable. It was his first vehicle with ABS. Your case is more understandable, though, and it is indeed normal. Enjoy your new car.
You said “turning over a slight rise?” on a smooth road or bumpy? ABS while turning is not normal on smooth pavement. Not even on smoothish gravel. The computer may need a program update if it really does this on turns.
Thanks for all your feedback. I feel much better. My other car didn’t have ABS. Euryale, I’ll make sure I have the dealer check it out on turns