BMW 2004 645Ci Convertible Manual Do Proprietário

 103

road surface. This phenomenon is referred 
to as hydroplaning, and is characterized 
by a partial or complete loss of contact 
between the tires and the road surface, ulti-
mately undermining your ability to steer 
and brake the vehicle.

<

The risk of hydroplaning increases as the 
tread depth of the tires decreases, also 
refer to Tire tread on page 

Do not drive through water on the 
road if it is deeper than 1 ft/30 cm, 

and then only at walking speed at the most. 
Otherwise, the vehicle's engine, the electri-
cal systems and the transmission may be 
damaged.

<

Your BMW is equipped with ABS as stan-
dard. The best way to achieve optimized 
braking response from the ABS is to apply 
maximum pressure to the brake pedal in 
situations where this is required: panic 
stops. 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 indi-
cate to the driver that ABS is in its active 
mode.

Do not drive with your foot resting on 
the brake pedal. Even light but con-

sistent pedal pressure can lead to high 
temperatures, brake wear and possibly 
even brake failure.

<

While 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 in this 
process helps dry the pads and rotors to 
ensure that full braking efficiency will then 
be available when you need it.

To prevent overheating and thus 
reduced efficiency of the brake sys-

tem, downshift to a gear in which only min-
imal brake applications are needed when 
descending long or steep downhill 
stretches. Even light but consistent pedal 
pressure can lead to high temperatures, 
brake wear and possibly even brake fail-
ure.

<

You can further enhance the engine's brak-
ing effect 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 

. This strategy helps you avoid 

placing excessive loads on the brake sys-
tem.

Never drive with the clutch pressed 
or allow the vehicle to coast with the 

transmission in Neutral – or with the engine 
switched off – there is no engine braking 
when the transmission is in Neutral, and no 
power assist for brakes and steering when 
the engine is not running.
Never allow floor mats, carpets or any other 
objects to protrude into the area around the 
accelerator and brake pedals and obstruct 
their movement.

<

When the vehicle is driven only occasion-
ally, 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 ten-
dency for corrosion to form on rotors, while 
contaminants accumulate on the brake 
pads. This occurs because the minimum 
pressure which 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 pul-
sating effect that even extended applica-
tion will fail to cure.

Online Edition for Part No. 01 41 0 157 980 - © 01/04 BMW AG