2008 BMW 7 Series Owner's Manual - Page 125

Hydroplaning When driving on wet or slushy roads, reduce road speed. If you do not, a wedge of water can form between tires and road surface. This phenomenon is referred to as hydroplaning, and is characterized by a partial or complete loss of contact between tires and road surface, ultimately undermining your ability to steer and brake the vehicle.< You can further enhance the engine's braking action by selecting a lower gear in the automatic transmission's manual mode, downshifting as far as first gear on extremely steep stretches, refer to page 63. This strategy helps you avoid placing excessive loads on the brake system. Do not drive in idle or with the engine switched off; otherwise, there will be no engine braking action or power-assist for the brakes and steering. Never allow floor mats, carpets or any other objects to protrude into the area of movement of the pedals and impair their operation.< Driving through water Only drive through water with a maximum depth of 1 ft/30 cm and then, at no more than walking speed. Otherwise, you run the risk of damaging the vehicle's engine, electrical systems, and transmission.< Corrosion on brake rotors When the vehicle is driven only occasionally, during extended periods when the vehicle is not used at all, and in operating conditions where brake applications are less frequent, there is an increased tendency for corrosion to form on rotors, while contaminants accumulate on the brake pads. This occurs because the minimal pressure that must be exerted by the pads during brake applications to clean the rotors is not reached. Should corrosion form on the brake rotors, the brakes will tend to respond with a pulsating effect that even extended application will fail to cure. Safe braking Your BMW is equipped with ABS as standard equipment. In situations that require it, it is best to apply the brakes fully. Since the vehicle maintains steering responsiveness, you can nevertheless avoid possible obstacles with a minimum of steering effort. Pulsation at the brake pedal combines with sounds from the hydraulic circuits to indicate to the driver that ABS is in its active mode. Driving in wet conditions When driving in wet conditions and in heavy rain, it is a good idea to apply light pressure to the brake pedal every few miles. Monitor traffic conditions to ensure that this maneuver does not endanger other road users. The heat generated helps dry the pads and rotors to ensure that full braking efficiency will then be available when you need it. When vehicle is parked Condensation forms in the automatic climate control during operation, and then exits under the vehicle. Traces of condensed water under the vehicle are therefore normal. Before driving into a car wash 1. Fold in the exterior mirrors, refer to page 50; otherwise, they could be damaged due to the width of the vehicle. To permit the vehicle to roll, follow the instructions on page 58. 2. Release the parking brake, especially when you have activated Automatic Hold. Refer to page 59. Hills To prevent overheating and reduced efficiency of the brake system, drive long or steep downhill grades in the gear that requires the least amount of braking. Otherwise, even light but consistent pedal pressure can lead to high temperatures, brake wear, and possibly even failure of the brake system.< 123 Online Edition for Part no. 01 41 0 013 316 - © 02/07 BMW AG Reference Mobility Communications Entertainment Navigation Driving tips Controls At a glance