99 Safety and Security
Driving safety systems
The electrohydraulic brake servo assis-
tance switches off automatically
approximately 2 minutes after you
turned the SmartKey in the starter
switch to position0 or removed the
SmartKey
approximately 2 minutes after you
pressed the KEYLESS-GO* start/stop
button to turn off the engine or power
supply and opened the driver’s door
(with driver’s door open, the starter
switch is set to position 0, same as
SmartKey removed from starter
switch)
approximately 20 seconds after you
locked the vehicle from outside.Note on driving with the electrohydrau-
lic brake system
Following extended periods of only mi-
nor loads to your brake system, you
should occasionally apply the brakes
when traveling at high speeds. This im-
proves the grip of the brake pads.
After driving on wet or snow-covered
roads, you should apply your brakes
firmly before parking your vehicle. This
produces heat which serves to dry the
brake disks and help prevent corro-
sion.
On long and steep grades, shift to a
lower gear (gear range1, 2, or 3) to
prevent the brakes from overheating
and to reduce brake wear.
Warning!
G
Have brake pad replacement and other work
on the electrohydraulic brake system car-
ried out by qualified technicians only. Con-
tact an authorized Mercedes-Benz Center
for further information. The electrohydraulic
brake system must be deactivated prior to
working on the system. High pressure is in-
termittently built up in the system as part of
its automatic self-test. In addition, the sys-
tem is automatically activated when the ve-
hicle is unlocked by SmartKey, when the
driver or passenger door is opened, when
the starter switch is turned to position
1,
when the brake pedal is depressed or when
the parking brake is released. Failure to de-
activate the system prior to maintenance
will cause brake pistons to extend and brake
fluid to leak, which may result in injuries
(contusions and acid burns). Extended
brake pistons may also cause injury.
Warning!
G
Be very careful not to endanger other road
users when you apply the brakes.
305 Operation
Driving instructions
To help prevent brake disk corrosion after
driving on wet road surfaces (particularly
salted roads), it is advisable to brake the
vehicle with considerable force prior to
parking. The heat generated serves to dry
the brakes.
If your brake system is normally only sub-
jected to moderate loads, you should occa-
sionally test the effectiveness of the
brakes by applying above-normal braking
pressure at higher speeds. This will also
enhance the grip of the brake pads.
Refer to the description of the Brake Assist
System (BAS) (
page 94).If the parking brake is released and the
brake warning lamp in the instrument clus-
ter stays on, there is a malfunction in the
electrohydraulic brake system (
page 97)
or the brake fluid level in the reservoir is
too low.
Brake pad wear or a leak in the system may
be the reason for low brake fluid in the res-
ervoir.
Have the brake system inspected by quali-
fied technicians immediately. Contact an
authorized Mercedes-Benz Center.
All checks and service work on the brake
system should be carried out by qualified
technicians only. Contact an authorized
Mercedes-Benz Center.
Only install brake pads and brake fluid
recommended by Mercedes-Benz.
After hard braking, it is advisable to drive
on for some time, rather than immediately
park, so that the air stream will cool down
the brakes faster.
Warning!
G
Make sure not to endanger any other road
users when carrying out these braking ma-
neuvers.
Warning!
G
If other than recommended brake pads are
installed, or other than recommended brake
fluid is used, the braking properties of the
vehicle can be degraded to an extent that
safe braking is substantially impaired. This
could result in an accident.
Be certain to read and observe the warning
notices on brake pad replacement
(page 400).!When driving down long and steep
grades, relieve the load on the brakes
by shifting into a lower gear to use the
engine’s braking power. This helps pre-
vent overheating of the brakes and re-
duces brake pad wear.
