2007 MERCEDES-BENZ G55AMG brakes

201 Controls in detail
Driving systems
The Rear Parking Assist system monitors
the rear surrounding of your vehicle with
four sensors in the rear bumper.
1SensorsRange of the sensors
To function properly, the sensors must be
free of dirt, ice, snow, and slush. Clean the
sensors regularly, being careful not to
scratch or damage the sensors, see
“Cleaning the Rear Parking Assist sensors”
(
page 318).
!During parking maneuvers, pay special
attention to objects located above or below the
height of the sensors (e.g. planters or trailer
hitches). The Rear Parking Assist system will not
detect such objects at close range and damage
to your vehicle or the object may result.
Ultrasonic signals from outside sources (e.g.
working jackhammers, car wash, or the air
brakes of trucks) may impair the operation of the
Rear Parking Assist system.

246 Operation
Driving instructions
Power assistance
BrakesTo 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
subjected to moderate loads, you should
occasionally 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.
Warning!G
With the engine not running, there is no
power assistance for the brake and steering
systems. In this case, it is important to keep
in mind that a considerably higher degree of
effort is necessary to brake and steer the
vehicle.
Warning!G
After driving in heavy rain for some time
without applying the brakes or through
water deep enough to wet brake compo-
nents or salty road conditions, the first brak-
ing action may be somewhat reduced and
increased pedal pressure may be necessary
to obtain expected braking effect. Maintain
a safe distance from vehicles in front.
Resting your foot on the brake pedal will
cause excessive and premature wear of the
brake pads.
It can also result in the brakes overheating,
thereby significantly reducing their effec-
tiveness. It may not be possible to stop the
vehicle in sufficient time to avoid an acci-
dent.
!Operational or performance test must only
be conducted on a two-axle dynamometer. If
such tests are necessary, contact an authorized
Mercedes-Benz Light Truck Center. You could
otherwise seriously damage the brake system or
the transfer case which is not covered by the
Mercedes-Benz Limited Warranty.
!Because the ESP® operates automatically,
the engine and ignition must be shut off
(SmartKey in starter switch position0 or1)
when testing the parking brake on a brake test
dynamometer and such testing should be no
longer than 10 seconds.
Active braking action through the ESP
® may
otherwise seriously damage the brake system
which is not covered by the Mercedes-Benz
Limited Warranty.
Warning!G
Make sure not to endanger any other road
users when carrying out these braking
maneuvers.

247 Operation
Driving instructions
Refer to the description of the Brake Assist
System (BAS) (
page 90).
Brake pad wear or a leak in the system may
be the reason for low brake fluid in the
reservoir.
The brake fluid level in the reservoir may
be too low if the brake warning lamp in the
instrument cluster comes on although the
parking brake is released (
page 326).
Observe additional messages in the
multifunction display that may appear
(
page 338).
Have the brake system inspected
immediately. Contact an authorized
Mercedes-Benz Light Truck Center.
All checks and service work on the brake
system should be carried out by qualified
technicians only. Contact an authorized
Mercedes-Benz Light Truck 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 the air stream will cool down the
brakes faster.
Driving off
Apply the brakes to test them briefly after
driving off. Perform this procedure only
when the road is clear of other traffic.
Warm up the engine smoothly. Do not
place full load on the engine until the
operating temperature has been reached.
To ensure sufficient traction during
off-road driving, activate differential locks
as needed (
page 175).
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.
!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 prevent overheating of the brakes and
reduces brake pad wear.
!When driving off on a slippery surface, do
not allow a drive wheel to spin for an extended
period with the ESP
® switched off. Doing so may
cause serious damage to the drivetrain which is
not covered by the Mercedes-Benz Limited
Warranty.
!Simultaneously depressing the accelerator
pedal and applying the brake reduces engine
performance and causes premature brake and
drivetrain wear.

249 Operation
Driving instructions
Treadwear indicators (TWI) are required by
law. These indicators are located in six
places on the tread circumference and
become visible at a tread depth of
approximately
1/16in (1.6 mm), at which
point the tire is considered worn and
should be replaced.
The treadwear indicator appears as a solid
band across the tread.Specified tire inflation pressures must be
maintained. This applies particularly if the
tires are subjected to high loads (e.g. high
speeds, heavy loads, high ambient temper-
atures).
For more information, see “Tires and
wheels” (
page 277).
Hydroplaning
Depending on the depth of the water layer
on the road, hydroplaning may occur, even
at low speeds and with new tires. Reduce
vehicle speed, avoid track grooves in the
road and apply brakes cautiously in the
rain.
Tire traction
The safe speed on a wet, snow covered or
icy road is always lower than on a dry road.
You should pay particular attention to the
condition of the road whenever the outside
temperatures are close to the freezing
point.
Warning!G
Although the applicable federal motor
vehicle safety laws consider a tire to be
worn when the treadwear indicators (TWI)
become visible at approximately
1/16in
(1.6 mm), we recommend that you do not
allow your tires to wear down to that level.
As tread depth approaches
1/8in (3.0 mm),
the adhesion properties on a wet road are
sharply reduced.
Depending upon the weather and/or road
surface (conditions), the tire traction varies
widely.
Warning!G
Do not drive with a flat tire. A flat tire affects
the ability to steer or brake the vehicle. You
may lose control of the vehicle. Continued
driving with a flat tire or driving at high
speed with a flat tire will cause excessive
heat build-up and possibly a fire.
Warning!G
If ice has formed on the road, tire traction
will be substantially reduced. Under such
weather conditions, drive, steer and brake
with extreme caution.

253 Operation
Driving instructions
Off-road driving
Read this chapter carefully before you
begin off-road travel.
Familiarize yourself with the vehicle
characteristics and gear changing before
you attempt any difficult terrain off-road
driving. We recommend that you start out
with easy off-road travel.Special driving features for off-road
driving
The following driving features are available
for specific kind of operation:

ABS (page 88)

ESP® (page 92)

4-ETS (page 91)

Differential lock (page 173)

Transfer case (page 170)
Off-road driving rules
Engage the transfer case in position
LOW before driving under off-road
conditions (
page 170).
If necessary activate differential locks
(
page 175).
The ABS, BAS and ESP
® are switched
off automatically when the differential
locks are activated.
Fasten items being carried as securely
as possible (
page 208).
Warning!G
Do not load items on the roof. It may cause
instability during some maneuvers which
could result in an accident.
Drive slowly in unknown terrain. This will
make it easier to recognize unexpected
obstacles and avoid damage to the vehicle.
To help avoid the vehicle rolling over, never
turn it around on steep inclines. If the vehi-
cle cannot complete the attempted climb,
back it down in reverse gear.
Do not drive along the side of a slope. The
vehicle might otherwise rollover. If in doing
so the vehicle begins to show a tendency to
roll, immediately steer into a line of gravity
(straight up or downhill).
Never let the vehicle roll backwards in idle.
You may lose control of the vehicle if you
use only the brake. For information on
driving downhill, see “Driving downhill”
(
page 257).
Warning!G
Sand, dirt, mud and other material having
friction property can cause exceptional wear
and tear as well as brake failure.
Have the brakes checked for dirt build-up
and cleaned. There is otherwise a risk that
full braking power may not be available in an
emergency.

256 Operation
Driving instructions

Driving on embankments, slopes and
other steep inclines should only be
done straight uphill or downhill, i.e. in
the line of gravity. Maximum vehicle
climbing ability is a 80% grade which is
equivalent to a slope angle of approxi-
mately 38 degrees. Keep in mind that
the climbing ability of the vehicle
depends on terrain conditions.

Select gear range2 or1 on the auto-
matic transmission (
page 167).

Drive slowly.

Utilize the engine’s braking power
when descending a slope, observe the
engine speed (do not overrev the
engine). Apply the service brake as
needed.

Check the brakes after a lengthy
downgrade drive.Traction in steep terrain
Be easy on the accelerator and watch for
continuous wheel traction when driving
uphill.
iFor maximum engine speed, see “Instru-
ment cluster” (
page 26) and see “Engine”
(
page 415).
Warning!G
Never turn the vehicle around on steep
inclines. The vehicle might roll over. If the
vehicle cannot complete the attempted
climb, back it down in reverse gear.
iThe 4-ETS helps greatly when starting out on
a steep incline when the front wheels have then
the tendency to slip due to the weight shifting
away from the front axle.
The 4-ETS recognizes the situation and limits the
torque for the front wheels by braking them.
Simultaneously the torque for the rear wheels is
provided.

258 Operation
Driving instructions

Comply with the warnings
(
page 253) and rules for off-road
driving (
page 253).

Switch off the exterior lamps as well as
the climate control.

Select gear range2 or1 on the auto-
matic transmission (
page 167).

Enter and leave the water only at a
shallow spot, driving at walking speed.

Drive through the water slowly and at a
constant speed.

Do not stop vehicle while immersed in
water, and do not shut off the engine.
There is a very high level of driving
resistance in water. The surface is
slippery and may not be firm, making
pulling away in water difficult and
dangerous.

Make sure that only small bow waves
are formed when driving the vehicle
through water.

Clean mud off the tire tread after
driving through water.

To dry the brakes, apply pressure to the
brake pedal several times after leaving
the water.Crossing obstacles
!Never accelerate before driving into the
water. The bow wave could force water into the
engine and auxiliary equipment, thus damaging
them.
!Do not open any of the vehicle’s doors while
driving through water. Water could otherwise en-
ter the vehicle interior and damage the vehicle’s
electronics, as well as the interior equipment.
!Obstacles can damage the vehicle
underbody or suspension components. If possi-
ble, use the assistance of a second person out-
side the vehicle to scout the path you intend to
take and check for adequate ground clearance
when you cross obstacles with your vehicle. The
person assisting you outside the vehicle should
always be a safe distance away from the vehicle
and positioned so that he or she cannot get hurt
in case of any unexpected vehicle movement.
After off-road driving or crossing obstacles,
inspect vehicle for any damage, especially
vehicle underbody and suspension components.
Failure to do so can adversely affect the vehi-
cle’s future performance, including increased
chance of an accident.

260 Operation
Driving instructions

Check the vehicle clearance before
driving in ruts.

Comply with the warnings
(
page 253) and rules for off-road
driving (
page 253).

Select gear range1 on the automatic
transmission (
page 167).

Drive slowly next to the ruts rather than
through them if at all possible.

If the ruts are too deep to drive in, drive
with one side of the vehicle on the
grassy center strip if the route permits.Returning from off-road drivingOff-road driving increases strain on the
vehicle.
We recommend that you inspect the vehi-
cle for possible damage after each off-road
trip. Recognizing any damage and a subse-
quent timely repair reduces the chance of
a possible breakdown or accident later on.
Proceed as follows:

Switch the transfer case in position
HIGH (
page 170).

Switch differential locks off
(
page 176).

Clean all exterior lamps and check
them for possible damage.

Clean the front and rear license plate.

Remove excessive dirt from tires,
wheels, wheel housings, and under-
body.
For instance, after driving in mud, clean
the radiator, chassis, engine, brakes,
and wheels from extreme dirt using a
strong jet of water.
After off-road driving or crossing obstacles,
inspect vehicle for any damage, especially
vehicle underbody and suspension components.
Failure to do so can adversely affect the vehi-
cle’s future performance, including increased
chance of an accident.
Warning!G
Never drive on pavement with activated
differential locks. Engaged front axle differ-
ential locks limits ability to move around
curves.
If you feel a sudden significant vibration or
ride disturbance, or you suspect that possi-
ble damage to your vehicle has occurred,
you should turn on the hazard warning flash-
ers, carefully slow down, and drive with cau-
tion to an area which is a safe distance from
the roadway.
Inspect the tires and under the vehicle for
possible damage. If the vehicle or tires
appear unsafe, have it towed to the nearest
Mercedes-Benz Light Truck Center or tire
dealer for repairs.
Damage to the vehicle may influence driving
comfort and poses the risk of accident to
you and other drivers.