A pair of Buick disc brake calipers can be found behind the front wheels of all models offered from this car maker. No longer are drum brakes used in the front of any American or import make of car being produced today. The use of the brake caliper over the old style drum drastically improves the ability to bring an automobile to a safe and controlled stop. This type of front braking system is now standard equipment on all American and most foreign vehicles. The function of the disc brake caliper on your Buick is to apply the necessary against force the discs that will slow or stop the forward or backward motion of your wheels as controlled by the driver. The friction it applies is to the disc brake pads, mounted as a pair inside of the brake caliper is what actually slows the brake rotors down. Buick is not the only car manufacturer to make this switch in style of braking components on their cars. Nearly all manufacturers in the world of automobiles have also done so for an increased level of safety and control. One of the few reasons for your Buick disc brake caliper would need to be replaced could be if water is present in the brake line that has made it way to the caliper itself. In your Buick, like all other makes on the road, the water will cause pitting of the brake calipers cylinder wall which could lead it to binding of the piston when the hydraulic pressure is applied to them. If this occurs, brake failure is a likely and bringing your car to a safe and controlled stop will not always be possible.