2003 MERCEDES-BENZ C320 COUPE wheel bolts

233 Operation
Tires and wheels
Tires and wheels
See your authorized Mercedes-Benz Cen-
ter for information on tested and recom-
mended rims and tires for summer and
winter operation. They can also offer ad-
vice concerning tire service and purchase
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.
See your authorized Mercedes-Benz Cen-
ter for information on tested and recom-
mended rims and tires for summer and
winter operation.
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.


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 Center for further informa-
tion. 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
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.

235 Operation
Tires and wheels
Tire pressure changes by approximately
1.5 psi (0.1 bar) per 18°F (10°C) of air
temperature change. Keep this in mind
when checking tire pressure where the
temperature is different from the outside
temperature.
Tire temperature and tire pressure are also
increased while driving, depending on the
driving speed and the tire load.Check the spare tire periodically for condi-
tion and inflation. Spare tires will age and
become worn over time even if never used,
and thus should be inspected and replaced
when necessary.
Rotating wheels
On vehicles with the same wheel size all
around, wheels can be rotated every 3000
to 6000 miles (5 000 to 10 000 km), or sooner if necessary, according to the de-
gree of tire wear. The same direction of tire
rotation must be retained.
Rotate the wheels before the characteris-
tic tire wear pattern becomes visible
(shoulder wear on front wheels and tread
center wear on rear wheels).
Thoroughly clean the inner side of the
wheels after each rotation. Check and en-
sure proper tire inflation pressure.
Warning!
G
Follow recommended inflation pressures.
Do not overinflate tires. Overinflating tires
can result in sudden deflation (blowout) be-
cause they are more likely to become punc-
tured or damaged by road debris, potholes
etc.
Do not underinflate tires. Underinflated tires
wear unevenly, adversely affect handling
and fuel economy, and are more likely to fail
from being overheated.
Do not overload the tires by exceeding the
specified vehicle capacity weight (as indicat-
ed by the label on the pillar in the driver’s
door opening). Overloading the tires can
overheat them, possibly causing a blowout.Warning!
G
Rotate front and rear wheels only if they are
of the same size.
Warning!
G
Have the tightening torque checked after
changing a wheel. Wheels could become
loose if not tightened with a torque of
80 ft.lb. (110 Nm).
Use only genuine Mercedes-Benz wheel
bolts specified for your vehicle's rims.

272 Practical hintsWhere will I find ...?Storing the spare wheel
Place spare wheel1 in wheel well.

Turn mounting screw3 clockwise to its
stop to secure the spare wheel.

Lower the trunk floor before closing the
trunk lid.
Vehicle tool kit
The vehicle tool kit and air pump are stored
in the wheel well below the trunk floor.
1Vehicle jack
2Air pump
3Alignment bolt
4Wheel wrench5Towing eye bolt
6Spare wheel bolts
Vehicle jack

Remove the vehicle jack from the spare
wheel well under the trunk floor.

Push the crank handle up.

Turn the crank handle clockwise until it
engages (operational position).
Before storing the vehicle jack in its com-
partment:


It should be fully collapsed.


The handle must be folded in (storage
position).

273 Practical hints
Where will I find ...?
Spare wheel bolts
1Wheel bolt for light alloy rims
2Wheel bolt for light alloy spare wheel
rim size 4
1/2B x15 H2Refer to “Technical data” section
(
page 313) for model and spare wheel
rim size information.
Warning!
G
The jack is designed exclusively for jacking
up the vehicle at the jack take-up brackets
built into both sides of the vehicle. To help
avoid personal injury, use the jack only to lift
the vehicle during a wheel change. Never
get beneath the vehicle while it is supported
by the jack. Keep hands and feet away from
the area under the lifted vehicle. Always
firmly set parking brake and block wheels
before raising vehicle with jack.
Do not disengage parking brake while the
vehicle is raised. Be certain that the jack is
always vertical (plumb line) when in use, es-
pecially on hills. Always try to use the jack
on level surface. Make sure that the jack
arm is fully seated in the jack take-up brack-
et. Always lower the vehicle onto sufficient
capacity jack stands before working under
the vehicle.
!Wheel bolts2 must be used when
mounting spare wheel rim
size 4
1/2Bx15 H2 (
page 313).
The use of any wheel bolts other than
wheel bolts2 for spare wheel rim
size 4
1/2B x15 H2 can cause physical
damage to the vehicle.
Warning!
G
Be sure to use the original length wheel
bolts when remounting the original wheel af-
ter it has been repaired.

289 Practical hints
Flat tire
When changing wheel on a hill:
Place chocks on the downhill side
blocking both wheels of the other axle.

Take the two-piece wheel wrench and
the jack out of the vehicle tool kit
(page 272). Assemble wheel wrench.

On whee l to b e change d, loos en b ut do
not yet remove the wheel bolts (ap-
proximately one full turn with wrench).
The jack take-up brackets are located di-
rectly behind the front wheel housings and
in front of the rear wheel housings.1Jack
2Crank
3Take-up bracket

Place jack on firm ground.

Position jack1 under the take-up
bracket3 so that it is always vertical
(plumb-line) as seen from the side,
even if the vehicle is parked on an in-
cline.

Jack up the vehicle until the wheel is a
maximum of 1.2 in (3 cm) from the
ground. Never start engine while vehi-
cle is raised.
Warning!
G
The jack is designed exclusively for jacking
up the vehicle at the jack take-up brackets
built into both sides of the vehicle. To help
avoid personal injury, use the jack only to lift
the vehicle during a wheel change. Never
get beneath the vehicle while it is supported
by the jack. Keep hands and feet away from
the area under the lifted vehicle. Always
firmly set parking brake and block wheels
before raising vehicle with jack.
Do not disengage parking brake while the
vehicle is raised. Be certain that the jack is
always vertical (plumb line) when in use, es-
pecially on hills. Always try to use the jack
on level surface. Make sure that the jack
arm is fully seated in the jack take-up brack-
et. Always lower the vehicle onto sufficient
capacity jackstands before working under
the vehicle.

290 Practical hintsFlat tireRemoving the wheel
1Alignment bolt
Unscrew upper-most wheel bolt and re-
move.

Replace this wheel bolt with the align-
ment bolt1 supplied in the tool kit.

Remove the remaining bolts.

Remove the wheel.

Take the spare tire out of the trunk.
Mounting the new wheel
1Wheel bolt for light alloy rims
2Wheel bolt for light alloy spare wheel
rim size 4
1/2B x15 H2

Clean contact surfaces of wheel and
wheel hub.

Guide the spare wheel onto the align-
ment bolt and push it on.

Insert wheel bolts and tighten them
slightly.

Inflate the spare tire using the electric
pump (
page 292).
!Do not place wheel bolts in sand or dirt.
This could result in damage to the bolt
and wheel hub threads.
!Wheel bolts2 must be used when
mounting spare wheel rim
size 4
1/2B x 15 H2 (
page 313).
The use of any wheel bolts other than
wheel bolts2 for spare wheel rim
size 4
1/2B x15 H2 can cause physical
damage to the vehicle.
Warning!
G
Be sure to use original lenght wheel bolts
when remounting the original wheel after it
has been repaired.Warning!
G
Inflate spare wheel with collapsible tire only
after the wheel is properly mounted.
Inflate the spare wheel tire using the electric
air pump before lowering the vehicle.


291 Practical hints
Flat tire

Unscrew the alignment bolt, install last
wheel bolt and tighten slightly.Lowering the vehicle

Lower vehicle by turning crank coun-
terclockwise until vehicle is resting ful-
ly on its own weight.

Remove the jack.
1-5 Wheel bolts

Tighten the five wheel bolts evenly, fol-
lowing the diagonal sequence illustrat-
ed (1 to 5), until all bolts are tight.
Observe a tightening torque of 80 ft lb
(110 Nm).
!To avoid paint damage, place wheel flat
against hub and hold it there while in-
stalling first wheel bolt.Warning!
G
Always replace wheel bolts that are dam-
aged or rusted.
Never apply oil or grease to wheel bolts.
Damaged wheel hub threads should be re-
paired immediately. Do not continue to drive
under these circumstances! Contact an au-
thorized Mercedes-Benz Center or call
Roadside Assistance.
Incorrect mounting bolts or improperly
tightened mounting bolts can cause the
wheel to come off. This could cause an acci-
dent. Be sure to use the correct mounting
bolts.
Warning!
G
Use only genuine equipment
Mercedes-Benz wheel bolts. They are identi-
fied by the Mercedes star. Other wheel bolts
may come loose.
Do not tighten the wheel bolts when the ve-
hicle is raised. Otherwise the vehicle could
tip over.


331 Technical terms
SRS
(S
upplemental R
estraint S
ystem)
Seat belts, emergency tensioning de-
vice and airbags. Though independent
systems, they are closely interfaced to
provide effective occupant protection.
Tele Aid* System
(T
elematic A
larm I
dentification on D
e-
mand)
The Tele Aid system consists of three
types of response: automatic and man-
ual emergency, roadside assistance
and information. Tele Aid is initially ac-
tivated by completing a subscriber
agreement and placing an acquain-
tance call.
The Tele Aid system is operational pro-
viding that the vehicle’s battery is
charged, properly connected, not dam-
aged and cellular and GPS coverage is
available.Tightening torque
Force times lever arm (e.g. a lug
wrench) with which threaded fasteners
such as wheel bolts are tightened.
Tire speed rating
Part of tire designation; indicates the
speed range for which a tire is ap-
proved.
Traction
Force exerted by the vehicle on the
road via the tires.VIN
(V
ehicle I
dentification N
umber)
The number set by the manufacturer
and placed on the body to uniquely
identify each vehicle produced.
Voice control system*
Voice control system for car phones,
portable cell phones and audio sys-
tems (radio, CD, etc.).