service BUICK CENTURY 2004 Service Manual

Brake Wear
Your vehicle has four-wheel disc brakes.
Disc brake pads have built-in wear indicators that make
a high-pitched warning sound when the brake pads
are worn and new pads are needed. The sound
may come and go or be heard all the time your vehicle
is moving (except when you are pushing on the
brake pedal rmly).
{CAUTION:
The brake wear warning sound means that
soon your brakes will not work well. That
could lead to an accident. When you hear the
brake wear warning sound, have your vehicle
serviced.Notice:Continuing to drive with worn-out brake
pads could result in costly brake repair.
Some driving conditions or climates may cause a brake
squeal when the brakes are rst applied or lightly
applied. This does not mean something is wrong with
your brakes.
Properly torqued wheel nuts are necessary to help
prevent brake pulsation. When tires are rotated, inspect
brake pads for wear and evenly tighten wheel nuts in
the proper sequence to GM torque specications.
Brake linings should always be replaced as complete
axle sets.Brake Pedal Travel
See your dealer if the brake pedal does not return to
normal height, or if there is a rapid increase in
pedal travel. This could be a sign of brake trouble.
Brake Adjustment
Every time you apply the brakes, with or without the
vehicle moving, your brakes adjust for wear.
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9. Connect the other end of the negative (−) cable at
least 18 inches (45 cm) away from the dead battery,
but not near engine parts that move. The electrical
connection is just as good there, and the chance
of sparks getting back to the battery is much less.10. Now start the vehicle with the good battery and run
the engine for a while.
11. Try to start the vehicle that had the dead battery. If
it will not start after a few tries, it probably needs
service.
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Headlamp Aiming
The vehicle has a headlamp system equipped with
horizontal and vertical aim indicators. The aim has been
pre-set at the factory and should need no further
adjustment. This is true even though the vertical and
horizontal aim indicators may not fall exactly on
the “0” (zero) marks on their scales.
If the vehicle is damaged in an accident, the headlamp
aim may be affected. Aim adjustment may be
necessary if it is difficult to see lane markers, for
horizontal aim, or if oncoming drivers ash their high
beams at you, for vertical aim. If you believe the
headlamps need to be re-aimed, we recommend that
you take it to your dealer for service; however, it is
possible for you to re-aim the headlamps as described
in the following procedure.
Notice:To make sure your headlamps are aimed
properly, read all the instructions before beginning.
Failure to follow these instructions could cause
damage to headlamp parts.To check the aim, the vehicle should be properly
prepared as follows:The headlamps must be off for one hour prior to
aiming and must remain off during this procedure.
The vehicle must have all four tires on a perfectly
level surface.
If necessary, pads may be used on an uneven
surface to help level the vehicle.
The vehicle should not have any snow, ice or mud
attached to it.
The vehicle should be fully assembled and all other
work stopped while headlamp aiming is being done.
There should not be any cargo or loading of
the vehicle. It should however, have a full fuel
tank and one person or 160 lbs (75 kg) on
the driver’s seat.
Close all doors.
Tires should be properly inated.
Rock the vehicle to stabilize the suspension.
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Tires
Your new vehicle comes with high-quality tires made by
a leading tire manufacturer. If you ever have questions
about your tire warranty and where to obtain service,
see your GM Warranty booklet for details. For additional
information refer to the tire manufacturer’s booklet
included with your vehicle’s Owner’s Manual.{CAUTION:
Poorly maintained and improperly used tires
are dangerous.
Overloading your tires can cause
overheating as a result of too much
friction. You could have an air-out and a
serious accident. See “Loading Your
Vehicle” in the Index.
Underinated tires pose the same danger
as overloaded tires. The resulting accident
could cause serious injury. Check all tires
frequently to maintain the recommended
pressure. Tire pressure should be checked
when your tires are cold.
Overinated tires are more likely to be
cut, punctured or broken by a sudden
impact — such as when you hit a pothole.
Keep tires at the recommended pressure.
Worn, old tires can cause accidents. If
your tread is badly worn, or if your tires
have been damaged, replace them.
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(A) Tire Size:The tire size code is a combination of
letters and numbers used to dene a particular
tire’s width, height, aspect ratio, construction type and
service description. See the “Tire Size” illustration
later in this section for more detail.
(B) Tire Performance Criteria Specication (TPC
Spec):Original equipment tires designed to GM’s
specic tire performance criteria have a TPC
specication code molded onto the sidewall. GM’s TPC
specications meet or exceed all federal safety
guidelines.
(C) Department of Transportation (DOT):The
Department of Transportation (DOT) code indicates that
the tire is in compliance with the U.S. Department of
Transportation Motor Vehicle Safety Standards.(D) Tire Identication Number (TIN):The letters and
numbers following DOT code are the Tire Identication
Number (TIN). The TIN shows the manufacturer
and plant code, tire size, and date the tire was
manufactured. The TIN is molded onto both sides of
the tire, although only one side may have the date
of manufacture.
(E) Tire Ply Material:The type of cord and number
of plies in the sidewall and under the tread.
(F) Uniform Tire Quality Grading (UTQG):Tire
manufacturers are required to grade tires based on
three performance factors: treadwear, traction and
temperature resistance. For more information see
Uniform Tire Quality Grading on page 5-70.
(G) Maximum Cold Ination Load Limit:Maximum
load that can be carried and the maximum pressure
needed to support that load. For more information on
recommended tire pressure seeInation - Tire Pressure
on page 5-64andLoading Your Vehicle on page 4-34.
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(F) Tire Size:A combination of letters and numbers
dene a tire’s width, height, aspect ratio, construction
type and service description. The letter “T” as the
rst character in the tire size means the tire is for
temporary use only.
(G) Tire Performance Criteria Specication
(TPC Spec):Original equipment tires designed to GM’s
specic tire performance criteria have a TPC
specication code molded onto the sidewall. GM’s TPC
specications meet or exceed all federal safety
guidelines.
Tire Size
The following illustration shows an example of a typical
passenger car tire size.(A) P-Metric Tire:The United States version of a
metric tire sizing system. The letter “P” as the
rst character in the tire size means a passenger
vehicle tire engineered to standards set by the
U. S. Tire and Rim Association.
(B) Tire Width:The three-digit number indicates the
tire section width in millimeters from sidewall to sidewall.
(C) Aspect Ratio:A two-digit number that indicates
the tire height-to-width measurements. For example, if
the tire size aspect ratio is “70,” as shown in item “C” of
the illustration, it would mean that the tire’s sidewall is
70% as high as it is wide.
(D) Construction Code:A letter code is used to
indicate the type of ply construction in the tire. The letter
“R” means radial ply construction; the letter “D” means
diagonal or bias ply construction; and the letter “B”
means belted-bias ply construction.
(E) Rim Diameter:Diameter of the wheel in inches.
(F) Service Description:These characters represent
the load range and the speed rating of a tire. The
load range represents the load carrying capacity a tire is
certied to carry. The load index can range from 1 to
279. The speed rating is the maximum speed a tire
is certied to carry a load. Speed ratings range from “A”
to “Z”.
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The system normally takes 15 to 20 minutes of driving
time in each of three speed ranges to determine
tire pressures. The speed ranges are 15 to 40 mph
(25 to 65 km/h), 40 to 65 mph (65 to 105 km/h)
and above 65 mph (105 km/h). When the storage of the
tire ination information is complete, the LOW TIRE
light will come on the instrument panel after two
to eight minutes if one tire is inated 12 psi (83 kPa)
less than the other three tires. Detection thresholds
may be higher and detection times may be longer on
rough roads, curves and at high speeds. The system is
not capable of ination differences at speeds greater
than 70 mph (110 km/h).
The tire ination monitor system will not alert you if the
pressure in more than one tire is low, if the system
is not properly calibrated, or if the vehicle is moving
faster than 70 mph (110 km/h).
The LOW TIRE light will stay on while the ignition is on,
until the system is resetDo not reset the tire ination monitor system without
rst correcting the cause of the problem and checking
and adjusting the pressure in all four tires. If the
system is reset when the tire pressures are incorrect, it
will not function properly and may not alert you when
a tire is low.
Any time a tire’s pressure is adjusted, the tires are
rotated, or one or more tires is repaired or replaced, the
tire ination monitor system will need to be reset. The
system also needs to be reset when new tires are
purchased and if the vehicle’s battery has been
disconnected.
To reset the system:
1. Turn the ignition to RUN.
2. Remove the passenger’s side instrument panel
cover to get to the fuse block.
3. Press and hold the RESET button in the fuse block
for about ve seconds.
4. The LOW TIRE light will come on and ash
three times. Then it will go off. If the light does
not go off, see your dealer for service.
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Buying New Tires
To nd out what kind and size of tires your vehicle
needs, look at the tire and loading information label. For
more information about this label and its location on
your vehicle, seeLoading Your Vehicle on page 4-34.
The tires installed on your vehicle when it was new had
a Tire Performance Criteria Specication (TPC Spec)
number on each tire’s sidewall. When you get new tires,
GM recommends that you get tires with that same
TPC Spec number. That way your vehicle will continue
to have tires that are designed to give proper
endurance, handling, speed rating, load range, traction,
ride and other things during normal service on your
vehicle. If your tires have an all-season tread design,
the TPC number will be followed by an “MS” (for
mud and snow).
If you ever replace your tires with those not having a
TPC Spec number, make sure they are the same
size, load range, speed rating and construction type
(bias, bias-belted or radial) as your original tires.{CAUTION:
Mixing tires could cause you to lose control
while driving. If you mix tires of different sizes
or types (radial and bias-belted tires), the
vehicle may not handle properly, and you
could have a crash. Using tires of different
sizes may also cause damage to your vehicle.
Be sure to use the same size and type tires on
all wheels. It’s all right to drive with your
compact spare temporarily, it was developed
for use on your vehicle. See “Compact Spare
Tire” in the index.
{CAUTION:
If you use bias-ply tires on your vehicle, the
wheel rim anges could develop cracks after
many miles of driving. A tire and/or wheel
could fail suddenly, causing a crash. Use only
radial-ply tires with the wheels on your vehicle.
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Uniform Tire Quality Grading
Quality grades can be found where applicable on the
tire sidewall between tread shoulder and maximum
section width. For example:
Treadwear 200 Traction AA Temperature A
The following information relates to the system
developed by the United States National Highway
Traffic Safety Administration, which grades tires by
treadwear, traction and temperature performance.
(This applies only to vehicles sold in the United States.)
The grades are molded on the sidewalls of most
passenger car tires. The Uniform Tire Quality Grading
system does not apply to deep tread, winter-type
snow tires, space-saver or temporary use spare tires,
tires with nominal rim diameters of 10 to 12 inches
(25 to 30 cm), or to some limited-production tires.
While the tires available on General Motors passenger
cars and light trucks may vary with respect to these
grades, they must also conform to federal safety
requirements and additional General Motors Tire
Performance Criteria (TPC) standards.
Treadwear
The treadwear grade is a comparative rating based on
the wear rate of the tire when tested under controlled
conditions on a specied government test course.
For example, a tire graded 150 would wear one and
a half (1.5) times as well on the government course as
a tire graded 100. The relative performance of tires
depends upon the actual conditions of their use,
however, and may depart signicantly from the norm
due to variations in driving habits, service practices and
differences in road characteristics and climate.
Traction – AA, A, B, C
The traction grades, from highest to lowest, are AA, A,
B, and C. Those grades represent the tire’s ability
to stop on wet pavement as measured under controlled
conditions on specied government test surfaces of
asphalt and concrete. A tire marked C may have poor
traction performance. Warning: The traction grade
assigned to this tire is based on straight-ahead braking
traction tests, and does not include acceleration,
cornering, hydroplaning, or peak traction characteristics.
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Vehicle Identication
Vehicle Identication Number (VIN)
This is the legal identier for your vehicle. It appears on
a plate in the front corner of the instrument panel, on
the driver’s side. You can see it if you look through the
windshield from outside your vehicle. The VIN also
appears on the Vehicle Certication and Service Parts
labels and the certicates of title and registration.
Engine Identication
The 8th character in your VIN is the engine code. This
code will help you identify your engine, specications
and replacement parts.
Service Parts Identication Label
This label is located on the inside of the trunk lid. It is
very helpful if parts need to be ordered for the vehicle. It
has the following information printed on it:
The VIN
The model designation
Paint information
A list of all production options and special
equipment
Do not remove this label from the vehicle.
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