check brake wear MERCEDES-BENZ S-Class 2011 W221 Owner's Manual

During sudden driving or braking maneuvers,
the objects could get caught between the
pedals. You could then no longer brake or
accelerate. This could lead to accidents and
injury.
Coasting with the engine switched offGWarning!
There is no power assistance for the steering
and the brake when the engine is not running.
Steering and braking requires significantly
more effort and you could lose control of the
vehicle and cause an accident as a result.
Do not turn off the engine while the vehicle is
in motion.
Exhaust check
GWarning
Inhalation of exhaust gas is hazardous to your
health. All exhaust gas contains carbon
monoxide (CO), and inhaling it can cause
unconsciousness and possible death.
Do not run the engine in confined areas (such
as a garage) which are not properly ventilated.
If you think that exhaust gas fumes are
entering the vehicle while driving, have the
cause determined and corrected
immediately. If you must drive under these
conditions, drive only with at least one
window fully open at all times.
Certain engine systems are designed to keep
the level of poisonous components in exhaust
fumes within legal limits.
These systems only work optimally if they are
maintained exactly in accordance with the
manufacturer's specifications. For this
reason, all work on the engine must be carried
out by qualified and authorized Mercedes-
Benz technicians.
The engine settings must not be changed in
any circumstances. Furthermore, all specific
service work must be carried out at regular
intervals and in accordance with the
Mercedes-Benz service requirements. Details
can be found in the Service Booklet.
Brakes
Important safety notes
GWarning
On slippery road surfaces, never downshift in
order to obtain braking action. This could
result in drive wheel slip and reduced vehicle
control. Your vehicle's ABS will not prevent
this type of loss of control.
GWarning
Make sure that you do not endanger other
road users when you apply the brakes.
Downhill gradients
! On long and steep gradients, you must
reduce the cargo on the brakes by shifting
to a lower gear in good time. This allows
you to take advantage of engine braking
and helps you to avoid overheating the
brakes and wearing them out excessively.
When you take advantage of engine
braking, a drive wheel may not turn for
some time, e.g. on a slippery road surface.
This could cause damage to the drive train.
Such damage is not covered by the
Mercedes-Benz warranty.
Heavy and light loads
GWarning
Depressing the brake pedal constantly results
in excessive and premature wear to the brake
pads.
It may also cause the brakes to overheat,
seriously impairing their effectiveness. It may
then not be possible to stop the vehicle in
sufficient time to avoid an accident.
If the brakes have been subjected to a heavy
cargo, do not stop the vehicle immediately,
320Driving tipsDriving and parking

but drive on for a short while. This allows the
airflow to cool the brakes more quickly.
Wet roadsGWarning
After driving in heavy rain for some time
without applying the brakes or through water
deep enough to wet brake components, the
first braking action may be somewhat
reduced. You have to depress the brake pedal
more firmly. Maintain a safe distance from
vehicles in front.
After driving on a wet road or having the
vehicle washed, brake firmly while paying
attention to the traffic conditions. This will
warm up the brake discs, thereby drying them
more quickly and protecting them against
corrosion.
Limited braking performance on salt
treated roads
GWarning
The layer of salt on the brake discs and the
brake pads/linings may cause a delay in the
braking effect, resulting in a significantly
longer braking distance, which could lead to
an accident.
To avoid this danger, you should:
R occasionally brake carefully, without
putting other road users at risk, when you
are driving on salted roads. This helps to
remove any salt that may have started to
build up on the brake discs and the brake
pads/linings.
R maintain a greater distance to the vehicle
ahead and drive with particular care.
R carefully apply the brakes at the end of a
trip and immediately after commencing a
new trip, so that salt residues are removed
from the brake discs.
Servicing the brakes
! If the red brake warning lamp lights up in
the instrument cluster and you hear a
warning tone while the engine is running,
the brake fluid level may be too low.
Observe additional warning messages in
the multifunction display.
The brake fluid level may be too low due to
brake pad wear or leaking brake lines.
Have the brake system checked
immediately. This work should be carried
out at an authorized Mercedes-Benz
Center.
All checks and maintenance work on the
brake system must be carried out at a
qualified specialist workshop. Contact an
authorized Mercedes-Benz Center.
Only install brake pads and use brake fluid
recommended by Mercedes-Benz.
GWarning
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.
! Vehicles with 4MATIC: a function or
performance test may only be carried out
on a two-axle dynamometer. If you are
planning to have the vehicle tested on such
a dynamometer, contact an authorized
Mercedes-Benz Center to obtain further
information first. Otherwise, the drive train
or the brake system may suffer damage.
! Vehicles with 4MATIC: as the ESP®
system operates automatically, the engine
and the ignition must be switched off
(SmartKey in position 0 or 1 in the ignition
lock or Start/Stop button in position 0 or
1 ) when the electric parking brake is being
tested on a brake dynamometer.
Braking maneuvers triggered automatically
by ESP ®
may seriously damage the brake
system.
Driving tips321Driving and parkingZ

! Vehicles with 4MATIC: as the ESP®
system operates automatically, the engine
and the ignition system must be switched
off (SmartKey in position 0 or 1 in the
ignition lock or Start/Stop button in
position 0 or 1) when:
R testing the electric parking brake on a
brake dynamometer.
R you intend to have the vehicle towed with
one of the axles raised.
Braking maneuvers triggered automatically
by ESP ®
may seriously damage the brake
system.
If your brake system is only subjected to
moderate loads, you should regularly test
your brake system's function by forcefully
depressing the brake pedal when driving at
high speed. This also improves the brake
pads' friction.GWarning
Make sure that you do not endanger other
road users when you apply the brakes.
A description of Brake Assist (BAS) can be
found on ( Y page 67) or of BAS PLUS on
( Y page 68).
High-performance brake system for
AMG vehicles
The high-performance brake system is only
installed on the S 63 AMG and S 65 AMG.
GWarning
New vehicle brake pads and discs, and
replacement brake pads and discs may take
several hundred miles of driving until they
provide optimum braking efficiency. Until that
time, you may need to use increased brake
pedal pressure while braking. Please be aware
of this and adjust your driving and braking
accordingly during this break-in period.
Excessive high-demand braking will cause
correspondingly high brake wear. Please be
attentive to the brake warning lamp in the
instrument cluster and brake condition
messages in the multifunction display.
Especially for high performance driving, it is
important to maintain and have the brake
system checked regularly.
The high-performance brake system is
designed for heavy loads. This may lead to
noise when braking. This will depend on:
R speed
R braking force
R environmental conditions, such as
temperature and humidity
The wear of individual components of the
brake system, such as the brake pads/linings
or brake discs, depends on the individual
driving style and operating conditions.
Driving on wet roads
Hydroplaning
If water has accumulated to a certain depth
on the road surface, there is a danger of
hydroplaning occurring, even if:
R you drive at low speeds
R the tires have adequate tread depth
For this reason, in the event of heavy rain or
in conditions in which hydroplaning can occur
you must drive in the following manner:
R Lower your speed
R Avoid ruts
R Brake carefully
Driving on flooded roads
! Do not drive through flooded areas.
Check the depth of any water before driving
through it. Drive slowly through standing
water. Otherwise, water may enter the
vehicle interior or the engine compartment.
This can damage the electronic
components in the engine or AUTOTRONIC.
Water can also be drawn in by the engine's
air suction nozzles and this can cause
engine damage.
322Driving tipsDriving and parking

Display messagesPossible causes/consequences and M SolutionsCruise Control
ohne
Funktion InoperativeCruise control is faulty.XVisit a qualified specialist workshop.Cruise Control
--- mphA condition for activating cruise control has not been met.
You wanted to save a speed of less than 20 mph (30 km/h).XIf the situation allows, drive faster than 20 mph ( 30 km/h) and
save the speed.XCheck the activation conditions for cruise control
( Y page 323).
Tires
GWarning
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 will cause excessive heat build-up
and possibly a fire.
GWarning
Follow recommended tire inflation pressures.
Do not underinflate tires. Underinflated tires wear excessively and/or unevenly, adversely affect
handling and fuel economy, and are more likely to fail from being overheated.
Do not overinflate tires. Overinflated tires can adversely affect handling and ride comfort, wear
unevenly, increase stopping distance, and result in sudden deflation (blowout) because they are
more likely to become punctured or damaged by road debris, potholes etc.
Display messagesPossible causes/consequences and M SolutionsTire Pressures
Displayed After
Driving A Few
MinutesThe tire pressure monitor is measuring the tire pressure.XDrive on.
The tire pressures appear in the multifunction display after you
have been driving for a few minutes.Tire Pressure
Monitor
InoperativeThe TPMS is faulty.XVisit a qualified specialist workshop.Tire Pressure
Monitor
Inoperative No
Wheel SensorsThe wheels mounted do not have a suitable tire pressure sensor.
The tire pressure monitor is deactivated.XMount wheels with suitable tire pressure sensors.
The TPMS is activated automatically after driving for a few
minutes.Display messages407On-board computer and displaysZ

"Technical Data" section to avoid damage
to the vehicle or the wheels.
R Only use snow chains when driving on an
area completely covered by snow. Do not
exceed the maximum permissible speed of
30 mph (50 km/h). Remove the snow
chains as soon as possible when you are no
longer driving on snow-covered roads.
R Local regulations may restrict the use of
snow chains. Applicable regulations must
be observed if you wish to mount snow
chains.
R Snow chains must not be mounted on
emergency spare wheels.
If you intend to mount snow chains, please
bear the following points in mind:
R you may not attach snow chains to all
wheel-tire combinations; see the "Tires and
wheels" section in the "Technical data"
chapter.
R mount snow chains only in pairs and only
on the rear wheels. Observe the
manufacturer's installation instructions.
! If snow chains are mounted on the front
wheels, the snow chains could grind
against the bodywork or components of the
chassis. This could result in damage to the
vehicle or the tires.
! Vehicles with steel wheels
If you wish to mount snow chains to steel
wheels, make sure that you remove the
respective wheels' hubcaps first. The
hubcaps may otherwise be damaged.
i You may wish to deactivate
ESP ®
(Y page 69) when pulling away with
snow chains installed. This way you can
allow the wheels to spin in a controlled
manner, achieving an increased driving
force (cutting action).Tire pressure
Tire pressure specifications
GWarning
Follow recommended tire inflation pressures.
Do not underinflate tires. Underinflated tires
wear excessively and/or unevenly, adversely
affect handling and fuel economy, and are
more likely to fail from being overheated.
Do not overinflate tires. Overinflated tires can
adversely affect handling and ride comfort,
wear unevenly, increase stopping distance,
and result in sudden deflation (blowout)
because they are more likely to become
punctured or damaged by road debris,
potholes etc.
Do not overload the tires by exceeding the
specified load limit as indicated on the Tire
and Loading Information placard on the
driver's door B-pillar. Overloading the tires
can overheat them, possibly causing a
blowout. Overloading the tires can also result
in handling or steering problems, or brake
failure.
You will find a table of recommended tire
pressures on the Tire and Loading
Information placard on the B-pillar on the
driver's side ( Y page 490). You will find a
table of tire pressures for various operating
conditions on the inside of your vehicle's fuel
filler flap.
Use a suitable pressure gauge. The outer
appearance of a tire does not permit any
reliable conclusion about the tire pressure.
On vehicles equipped with the electronic tire
pressure monitor, the tire pressure can be
checked using the on-board computer.
GWarning
Should the tire pressure drop repeatedly:
Tire pressure483Tires and wheelsZ

Rfail from being overheated
R adversely affect handling
Overinflated tiresGWarning
Follow recommended tire inflation pressures.
Do not overinflate tires. Overinflated tires can
adversely affect handling and ride comfort,
wear unevenly, increase stopping distance,
and result in sudden deflation (blowout)
because they are more likely to become
punctured or damaged by road debris,
potholes etc.
Overinflated tires can:
R adversely affect handling
R wear excessively and/or unevenly
R be more likely to become damaged
R adversely affect ride comfort
R increase stopping distance
Maximum tire pressure
GWarning
Never exceed the maximum tire inflation
pressure. Follow recommended tire inflation
pressures.
Do not underinflate tires. Underinflated tires
wear excessively and/or unevenly, adversely
affect handling and fuel economy, and are
more likely to fail from being overheated.
Do not overinflate tires. Overinflated tires can
adversely affect handling and ride comfort,
wear unevenly, increase stopping distance,
and result in sudden deflation (blowout)
because they are more likely to become
punctured or damaged by road debris,
potholes etc.
:Maximum permitted tire pressure
(example)
i The actual values for tires are specific to
each vehicle and may deviate from the
values in the illustration.
When adjusting the tire pressures always
observe the recommended tire pressure for
your vehicle ( Y page 483).
Checking tire pressures
Important safety notes
GWarning
Follow recommended tire inflation pressures.
Do not underinflate tires. Underinflated tires
wear excessively and/or unevenly, adversely
affect handling and fuel economy, and are
more likely to fail from being overheated.
Do not overinflate tires. Overinflated tires can
adversely affect handling and ride comfort,
wear unevenly, increase stopping distance,
and result in sudden deflation (blowout)
because they are more likely to become
punctured or damaged by road debris,
potholes etc.
Do not overload the tires by exceeding the
specified load limit as indicated on the Tire
and Loading Information placard on the
driver's door B-pillar. Overloading the tires
can overheat them, possibly causing a
blowout. Overloading the tires can also result
in handling or steering problems, or brake
failure.
486Tire pressureTires and wheels

Tire bead
The tire bead ensures that the tire sits
securely on the wheel. There are several steel
wires in the bead to prevent the tire from
coming loose from the wheel rim.
Sidewall
The part of the tire between the tread and the
tire bead.
Weight of optional extras
The combined weight of those optional extras
that weigh more than the replaced standard
part and more than 2.3 kilograms (5 lbs).
These optional extras, such as high-
performance brakes, level control, a roof rack
or a high-performance battery, are not
included in the unladen weight and the weight
of the accessories.
TIN (Tire Identification Number)
A unique identification number which can be
used by a tire manufacturer to identify tires,
for example for a product recall, and thus
identify the purchasers. The TIN is made up
of the manufacturer's identity code, tire size,
tire type code and the manufacturing date.
Load bearing index
The load bearing index (also load index) is a
code that contains the maximum load bearing
capacity of a tire.
Traction
Traction is the result of friction between the
tires and the road surface.
Wear indicator
This is indicated by narrow bars (tread wear
bars) that are distributed over the tire tread.
If the tire tread is level with the bars, the wear
limit of 1
/ 16 in (1.6 mm) has been reached.
Distribution of the vehicle occupants
This is the distribution of vehicle occupants
over designated seat positions in a vehicle.
Maximum permissible payload
weight
Nominal load and luggage load plus
68 kilograms (150 lb) multiplied by the
number of seats in the vehicle.
Changing a wheel
Flat tire
The "Breakdown assistance" section
( Y page 463) contains information and notes
on how to deal with a flat tire. It also provides
instructions on changing a wheel or installing
the spare wheel or emergency spare wheel.
Interchanging the wheels
GWarning
Rotate front and rear wheels only if the tires
are of the same dimension.
If your vehicle is equipped with mixed-size
tires (different tire dimensions front vs. rear),
tire rotation is not possible.
GWarning!
Have the tightening torque checked after
changing a wheel. The wheels could come
loose if they are not tightened to a torque of
110 lb-ft (150 Nm).
Only use genuine Mercedes-Benz wheel bolts
specified for your vehicle’s rims.
502Changing a wheelTires and wheels

The wear patterns on the front and rear tires
differ, depending on the operating conditions.
Rotate the wheels before a clear wear pattern
has formed on the tires. Front tires typically
wear more on the shoulders and the rear tires
in the center.
If your vehicle's tire configuration allows, you
can rotate the wheels according to the
intervals in the tire manufacturer's warranty
book in your vehicle documents. If no
warranty book is available, the tires should be
rotated every 3000 to 6000 miles
(5000 to 10000 km), or earlier if tire wear
requires. Do not change the direction of
wheel rotation.
Clean the contact surfaces of the wheel and
the brake disc thoroughly every time a wheel
is interchanged. Check the tire pressures.
Information on changing a wheel and fitting
the spare wheel ( Y page 463).
! On vehicles installed with a tire pressure
monitor, electronic components are
located in the wheel.
Tire-mounting tools should not be applied
in the area of the valve, as this could
damage the electronic components.
Always have the tires changed at a qualified
specialist workshop, e.g. an authorized
Mercedes-Benz Center.
Direction of rotation
Tires with a specified direction of rotation
have additional benefits, e.g. if there is a risk
of hydroplaning. You will only gain these
benefits if the correct direction of rotation is
observed.
An arrow on the sidewall of the tire indicates
its correct direction of rotation.
You may install an emergency spare wheel/
spare wheel against the direction of rotation.
Observe the time restriction on use as well as
the speed limitation specified on the
emergency spare wheel/spare wheel.
Storing wheels
Store wheels that are not being used in a cool,
dry and preferably dark place. Protect the
tires from contact with oil, grease and fuel.
Cleaning the wheels
GWarning
Do not use power washers with circular jet
nozzles (concentrated-power jets) to clean
your vehicle, especially for cleaning tires. You
could otherwise damage the tires and cause
an accident.
Wheel/tire combinations
Points to remember
GWarning
Observe the "Important safety notes"
( Y page 480).
! For safety reasons, Mercedes-Benz
recommends that you only use tires,
wheels and accessories which have been
approved by Mercedes-Benz specifically
for your vehicle.
These tires have been specially adapted for
use with the control systems, such as ABS
or ESP ®
, and are marked as follows:
R MO = Mercedes-Benz Original
R MOE = Mercedes-Benz Original Extended
(tires with run-flat characteristics)
R MO1 = Mercedes-Benz Original (only
certain AMG tires)
Mercedes-Benz Original Extended tires
may only be used on wheels that have been
specifically approved by Mercedes-Benz.
Only use tires, wheels or accessories
tested and approved by Mercedes-Benz.
Certain characteristics, e.g. handling,
vehicle noise emissions or fuel
consumption, may otherwise be adversely
affected. In addition, when driving with a
Wheel/tire combinations503Tires and wheelsZ