2003 MERCEDES-BENZ G55AMG brakes

198 OperationDriving instructionsPower assistanceBrakesTo 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.If the parking brake is released and the
brake warning lamp in the instrument clus-
ter stays on and there is no audible warn-
ing (EBB), 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 at an au-
thorized Mercedes-Benz Light Truck Cen-
ter immediately.
All checks and service work on the brake
system should be carried out by an autho-
rized Mercedes-Benz Light Truck Center.
Install only brake pads and brake fluid
recommended by Mercedes-Benz.Warning!
G
When the engine is 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 stop or steer the vehi-
cle.Warning!
G
After driving in heavy rain for some time
without applying the brakes or through wa-
ter deep enough to wet brake components
or salty road conditions, the first braking ac-
tion may be somewhat reduced and in-
creased 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.
!Be very careful not to endanger other
road users when you apply the brakes.
Refer to the description of the Brake
Assist System (BAS) (
page 73).

199 Operation
Driving instructions
After hard braking, it is advisable to drive
on for some time, rather than immediately
parking, 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 oper-
ating temperature has been reached.
When starting off on a slippery surface, do
not allow one drive wheel to spin for an ex-
tended 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.
To ensure sufficient traction during
off-road driving, activate differential locks
as needed (
page 145).
Parking
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 selecting gear range3,2 or1 on the
automatic transmission to use the en-
gine’s braking power (
page 137).
This helps prevent overheating of the
brakes and reduces brake pad wear.
Warning!
G
Do not park this vehicle in areas where com-
bustible materials such as grass, hay or
leaves can come into contact with the hot
exhaust system, as these materials could be
ignited and cause a vehicle fire.
To reduce the risk of personal injury as a re-
sult of vehicle movement, before
turning off
the engine and leaving the vehicle always:


Keep right foot on brake pedal.


Pull the parking brake lever up as many
notches as possible.


Move the selector lever to positionP.


Slowly release brake pedal.


When parked on an incline, turn front
wheel towards the road curb.


Turn the key to starter switch position0
and remove.


Take the key and lock vehicle when leav-
ing.

200 OperationDriving instructionsTiresTread wear indicators (TWI) are required by
law. These indicators are located in six
places on the tread circumference and be-
come visible at a tread depth of approxi-
mately
1⁄16
in (1.5 mm), at which point the
tire is considered worn and should be re-
placed.
The tread wear indicator appears as a solid
band across the tread.
Specified tire pressures must be main-
tained. This applies particularly if the tires
are subject to high loads (e.g. high speeds,
heavy loads, high ambient temperatures).
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.
!Set the parking brake whenever park-
ing or leaving the vehicle. In addition,
move selector lever to positionP. In ad-
dition, when parking on hills, always set
the parking brake and turn front wheel
towards the curb.Warning!
G
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-
ti o n to a n a r ea wh ic h i s a s a fe dis t an c e f ro m
the road.
Inspect the tires and the vehicle underbody
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.
Warning!
G
Do not allow your tires to wear down too far.
As tread depth approaches
1⁄16in (1.5 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.

204 OperationDriving instructionsRead this chapter carefully before you be-
gin off-road travel.
Familiarize yourself with the vehicle char-
acteristics and gear changing before you
attempt any difficult terrain off-road driv-
ing. 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 71)


ESP (
page 75)


4-ETS (
page 74)


Differential lock (
page 145)


Transfer case (
page 141)
Off-road driving rules

Engage the transfer case in position
LOW before driving under off-road con-
ditions (
page 141).

If necessary activate differential locks
(page 145).
The ABS, BAS and ESP are switched off
automatically when the differential
locks are activated.

Fasten items being carried as securely
as possible (
page 173).
Never let the vehicle roll backwards in idle.
You may lose control of the vehicle if you
use only the service brake.
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.
iWhenever driving in off-road mode, we
recommend:

Keeping doors, tailgate, windows
and sliding/pop-up roof closed.


Switching cruise control off.
!Observe the following during off-road
driving:

Adjust vehicle speed to condition of
terrain. The more uneven, rutty and
steeper the terrain, the lower the
speed should be. Drive through wa-
ter slowly at an even speed, avoid-
ing a bow wave.


Be especially careful when driving
in unknown territory. It may be nec-
essary to get out of the vehicle and
scout the path you intend to take.


Watch out for obstacles, such as
rocks, holes, tree stumps and ruts.

206 OperationDriving instructionsDriving in steep terrainSlope angle127°
236°

Comply with the warnings
(page 203) and rules for off-road
driving (
page 204).


Driving on embankments, slopes and
other steep inclines should only be
done straight up or downhill, i.e. in the
line of gravity. Maximum vehicle climb-
ing ability is a 80% grade.


Select gear range2 or1 on the auto-
matic transmission (
page 137).


Drive slowly.


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


Check the brakes after a lengthy down-
grade drive.
Traction in steep terrain
Be easy on the accelerator and watch for
continuous wheel traction when driving in
steep terrain.Driving across a hilltop
Decelerate just ahead of a hilltop (do not
select gear rangeN), to prevent the vehi-
cle from speeding up too much after climb-
ing a hill.
Use the momentum of the vehicle to drive
across the hilltop.
After climbing a hill, driving in this manner
prevents the vehicle from:


jumping across the hilltop


loosing its forward momentum.


speeding up too much after climbing
the hill.
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 the
front axle.The 4-ETS recognizes the sit-
uation and limits the torque for the
front wheels by braking them. Simulta-
neously the torque for the rear wheels
is provided.

207 Operation
Driving instructions
Driving downhill

Select gear range1 on the automatic
transmission (
page 137).


Drive downhill observing the same
rules as driving uphill (
page 206).Driving through water
119 in (48 cm)


Before driving through water, deter-
mine its depth.
It should not be deeper than approxi-
mately 19 in (48 cm).


Comply with the warnings
(page 203) and rules for off-road
driving (
page 204).


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


Select gear range2 or1 on the auto-
matic transmission (
page 137).


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


Do not stop vehicle immersed in water,
and do not shut off the engine.
There is a very high level of driving re-
sistance in water. The surface is slip-
pery and may not be firm, making
pulling away in water difficult and dan-
gerous.


Clean mud off the tire tread after driv-
ing through water.


To dry the brakes, apply pressure to the
brake pedal several times after leaving
the water.
!Only apply the service brake if the vehi-
cle travels straight downhill, i.e. in the
line of gravity.iThe special LOW RANGE – ABS setting
allows for precise and brief (cyclical)
blocking of the front wheels, permitting
them to dig into loose ground.
Remember that, when stopped, the
front wheels slide across a surface and
thus lose their ability to steer the vehi-
cle.
!Never accelerate before driving into
the water. The bow wave could force
water into the engine and auxiliary
equipment, thus damaging them.

210 OperationDriving instructionsOff-road driving increases strain on the ve-
hicle.
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 141).


Disengage differential locks
(page 146).


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.


Inspect frame, oil pan, brake hoses,
etc., as well as vehicle underbody for
possible damage.


Check tires for possible damage and
remove foreign objects. Clean all exte-
rior lamps and conduct a brake test.


Clean all exterior lamps and check
them for possible damage.


Check for brush or branches caught in
the undercarriage.
They could increase the possibility of a
fire, as well as cut fuel and/or brake
lines, puncture rubber bellows of the
axles or drive shafts.


After continued operation in mud,
sand, water or other dirty conditions,
clean the brake discs, wheels, brake
pads and check and clean axle joints.


Conduct a brake test.Control and operation of radio trans-
mitters
COMAND, radio and telephone*Warning!
G
Do not forget that your primary responsibili-
ty is to drive the vehicle safely. Only operate
the COMAND, radio or telephone
1 if road,
traffic and weather conditions permit.
Bear in mind that at a speed of just 30 mph
(approximately 50 km / h), your vehicle is
covering a distance of approximately
50 feet (approximately 14 m) every second.
1Observe all legal requirements.

224 OperationTires and wheels
Tires and wheelsSee your authorized Mercedes-Benz Light
Truck Center for information on tested and
recommended rims and tires for summer
and winter operation. They can also offer
advice concerning tire service and pur-
chase.
Retread tires are not tested or recom-
mended by Mercedes-Benz, since previous
damage cannot always be recognized on
retreads. Mercedes-Benz can therefore
not assure the operating safety of the vehi-
cle when such tires are used.
Important guidelines

Use only sets of tires and rims of the
same type and make.


Tires must be of the correct size for the
rim.


Break in new tires for approximately
60 miles (100 km) at moderate
speeds.


Regularly check the tires and rims for
damage. Dented or bent rims can
cause tire pressure loss and damage to
the tire beads.


If vehicle is heavily loaded, check tire
pressure and correct as required.


Do not allow your tires to wear down
too far. Adhesion properties on wet
roads are sharply reduced at tread
depths under
1⁄8in (3 mm).


When replacing individual tires, you
should mount new tires on the front
wheels first (on vehicles with
same-sized wheels all around).
Warning!
G
Replace rims or tires with the same designa-
tion, manufacturer and type as shown on the
original part. See your authorized
Mercedes-Benz Light Truck Center for fur-
ther information. If incorrectly sized rims
and tires are mounted:

The wheel brakes or suspension compo-
nents can be damaged.


The correct operating clearance of the
wheels and the tires are no longer guar-
anteed.
Warning!
G
Do not mix different tire construction types
(i.e. radial, bias, bias-belted) on your vehicle
because handling may be adversely affected
and may result in loss of control.Warning!
G
Worn, old tires can cause accidents. If the
tire tread is badly worn, or if the tires have
sustained damage, replace them.
When replacing rims, use only genuine
Mercedes-Benz wheel bolts specified for the
particular rim type. Failure to do so can re-
sult in the bolts loosening and possibly an
accident.