The cause of vibration during brake application is that the rotors are not running in a perfectly flat state. This can be cause by a few different things such as being warped from heat or over-torqueing of the lug nuts, having brake pad deposits build up in one area and distort the thickness enough to cause a vibration, or with lower quality rotors, there is an increased chance for there being soft spots in the casting. If these are OEM or equivalent quality, the last one will most likely not apply.

The most likely cause is that the rotors are warped. But no matter what the cause of the thickess variation, the solution would be to replace the brake rotors.

Vibration during driving can be any number of things but is frequently caused by tires being improperly balanced or being out of round.

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Ali Al-Chalabi

2001 CLK55
1999 Dodge Ram 2500 Cummins Diesel
2002 Harley-Davidson Fatboy
Merlin Extralight w/ Campy Record