2004 MERCEDES-BENZ C320 COUPE wheel bolts

244 OperationTires and wheels
Tires and wheelsSee 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
Retreaded 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. 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 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.

246 OperationTires and wheelsTire 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
b e c o m e w o r n o v e r t i m e e v e n i f n e v e r u s e d ,
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 lb-ft (110 Nm).
Use only genuine Mercedes-Benz wheel
bolts specified for your vehicle's rims.

285 Practical hints
Where will I find ...?
Spare wheel
The spare wheel is located under the trunk
floor.
Removing the spare wheel
Lift trunk floor and engage handle in
the upper edge of the trunk.
1Spare wheel
2Storage tray with vehicle tool kit
3Mounting screw for spare wheel/cover
for vehicle tools

Turn the mounting screw3 counter-
clockwise.

Remove the spare wheel1.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 wrench
5Towing eye bolt
6Spare wheel bolts

287 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 H2For more information on model and spare
wheel rim size, see “Technical data” sec-
tion (
page 326).
!Wheel bolts2 must be used when
mounting spare wheel rim
size 4
1/2Bx15 H2 (
page 326).
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
Make sure to use the original length wheel
bolts when remounting the original wheel af-
ter it has been repaired.

302 Practical hintsFlat tireWhen 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 285). Assemble wheel wrench.

On wheel to be changed, loosen but 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 the jack arm is
fully seated in the jack take-up bracket. Al-
ways lower the vehicle onto sufficient ca-
pacity jackstands before working under the
vehicle.

303 Practical hints
Flat tire
Removing 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.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 304).
!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
1/2Bx15 H2 (
page 326).
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
Make sure to use original length 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.

304 Practical hintsFlat tire

Unscrew the alignment bolt, install last
wheel bolt and tighten slightly.Inflating the spare tire

Take the electric air pump out of the
trunk.
1Flap
2Air hose with pressure gauge and vent
screw
3Union nut
4Electrical plug
Please exercise appropriate caution
!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 wheel bolts or improperly tight-
ened wheel bolts can cause the wheel to
come off. This could cause an accident.
Make sure to use the correct mounting
bolts.
Warning!
G
Use only genuine equipment
Mercedes-Benz wheel bolts. Other wheel
bolts may come loose.
Do not tighten the wheel bolts when the ve-
hicle is raised. Otherwise the vehicle could
tip over.
Warning!
G
Observe instructions on air pump label.

306 Practical hintsFlat tireLowering 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
illustrated (1 to 5), until all bolts are
tight. Observe a tightening torque of
80 lb-ft (110 Nm).

Before storing the jack in the trunk, it
should be fully collapsed, with handle
folded in.Warning!
G
Have the tightening torque checked after
changing a wheel. The wheels could come
loose if they are not tightened to a torque of
80 lb-ft (110 Nm).