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Anti-lock brakes with worn disk rotors

(I thought you might share this with your readers/listeners)

I have been noticing a slight vibration in the steering wheel of my Toyota Avalon when I apply the brakes. Recently I took a trip to the frozen TUNDRA of Iowa and got on some slick snow over icy roads. When I lightly apply the brakes, the anti-lock system immediately kicked in and I felt like I was out of control; in fact I was. I could not even slightly touch the brake pedal. Lucky, I had plenty of distance to slow down! (Now, I think you may want to explain this to your readers/listeners)

What happened? I know the answer; disk rotors were worn causing some areas on the disk to be thicker, thus causing the steering wheel to vibrate when the pad hit the high spots. On the slick raod, this caused that wheel to “lock up”, thereby causing the anti-lock system to think the car was in a skid, and it started to jam the brakes on and off. I managed to stop the car by ‘just letting the anti-lock system do its thing’, but it was a scary ride. So, if you would explain the symptoms of worn rotors and the possible results of ignoring that minor irritation, you might help prevent an accident. I am sure you can find some humorous things to say.

which may be why dealers tend to replace the rotors when they replace the pads (aside from the $$ reason).

The warped rotors could cause some problems. The ABS does feel bad when it comes on, but it you just let it do it’s thing, it really is safer. It sounds like the ABS is working properly. On modern cars they have lightened the disk so they really should be replaced along with the pads.

The rotors are not worn so it would have thin spots. The rotors become warped from heat thus causing high spots. In your case, dangerous, most often just plain annoying.

Due to reduced weight of the rotors it is usually best to replace them anytime the brakes are replaced. After you factor in resurfacing rotors it is likely cheaper to just replace them. Use good rotors, not the cheap made in China ones.

I can’t think of anything humorous about driving on ice. The warped rotors MAY have contributed to the problem you had, but more likely, the main problem was that frozen H2O. But top-notch brakes are a must for all driving, and moreso in adverse weather conditions. Thanks for the reminder.

BTW, if you were expecting Tom and Ray to respond, you will be disappointed. They occasionally pose a question, but I’ve never seen them respond to one here.