Whenever I apply the brakes when driving my 2002 Honda minivan, the steering wheel vibrates. The higher the speed when braking, the greater the vibration. I have taken the car to two different garages and they both say that the brakes are fine and that there is nothing wrong. How can this be so? – Don
I'd look for a different shop! A vibration of the steering wheel under braking usually means a brake rotor or drum that has become warped or out of round.
This is normally caused by heat created by extended hard braking, but can also be related to the rotor being immersed in water when hot, such as driving through a deep puddle.
Regardless of the cause, when the brakes are applied and the calipers squeeze the pads against the out-of-round rotor, the resulting vibration us transferred to the steering system. As you can imagine, the speed the brake rotor is turning determines the frequency of the vibration.
To picture what is going on, think of a bicycle wheel and how the brakes work – when you pull on the brake handle, the little black pads squeeze against the edge of the wheel and the resulting friction slows the bike – creating heat in the process. If the wheel is not perfectly round or there is a bump on the rim, you will feel the vibration.
It is possible your vibration is only slight and does not manifest itself clearly when the rotors are cold. In such cases, a cursory inspection or short road test would not show the problem. The best test is to use a micrometer caliper to determine the run-out of the rotor.
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