Tire BUICK LESABRE 2002 Service Manual

6-36
If your vehicle is damaged in an accident, the headlamp
aim may be affected. Aim adjustment to the low beam
may be necessary if it is difficult to see lane markers
(for horizontal aim), or if oncoming drivers flash their
high beams at you (for vertical aim). If you believe your
headlamps need to be re
-aimed, we recommend that
you take your vehicle to your dealer for service.
However, it is possible for you to re
-aim your
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.
The vehicle should be properly prepared as follows:

The vehicle should be placed so the headlamps
are 25 ft. (7.6 m) from a light colored wall or other
flat surface.

The vehicle must have all four tires on a perfectly
level surface which is level all the way to the wall or
other flat surface.

The vehicle should be placed so it is perpendicular
to the wall or other flat surface.

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.

The vehicle should be normally loaded with a full
tank of fuel and one person or 160 lbs. (75 kg) on
the driver's seat.

Tires should be properly inflated.
Headlamp aiming is done with the vehicle low beam
lamps. The high beam lamps will be correctly aimed if
the low beam lamps are aimed properly.
The headlamp aiming devices are under the hood near
the headlamps.

6-40 Front Turn Signal
Once the headlamp assembly has been removed from
the vehicle, the front turn signal bulbs can be accessed.
1. Reach down into the space provided by the removal
of the headlamp assembly and, while pushing in the
tab on the bulb assembly, turn the assembly
counterclockwise and remove it.
2. Remove the old bulb by pulling it straight out of
the retainer.
3. Install the new bulb and turn the bulb assembly
back into place.
Trunk-Mounted Back-Up and Taillamps
1. Loosen and remove the seven fasteners that hold
the assembly in place. The assembly for both sides
is one piece. The entire piece must be removed to
replace any bulbs.

6-44
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 Buick Warranty booklet for details.
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 ªLoading Your Vehicleº in
the Index.
CAUTION: (Continued)
CAUTION: (Continued)

Underinflated 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.

Overinflated 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.

6-45 Inflation -- Tire Pressure
The Tire-Loading Information label, which is on the
rear edge of the driver's door, shows the correct
inflation pressures for your tires when they're cold.
ªColdº means your vehicle has been sitting for at least
three hours or driven no more than 1 mile (1.6 km).
NOTICE:
Don't let anyone tell you that underinflation or
overinflation is all right. It's not. If your tires
don't have enough air (underinflation), you can
get the following:

Too much flexing

Too much heat

Tire overloading

Bad wear

Bad handling

Bad fuel economy
NOTICE: (Continued)
NOTICE: (Continued)
If your tires have too much air (overinflation),
you can get the following:

Unusual wear

Bad handling

Rough ride

Needless damage from road hazards
When to Check
Check your tires once a month or more.
Don't forget your compact spare tire. It should be at
60 psi (420 kPa).
How to Check
Use a good quality pocket
-type gage to check tire
pressure. You can't tell if your tires are properly inflated
simply by looking at them. Radial tires may look
properly inflated even when they're underinflated.
Be sure to put the valve caps back on the valve stems.
They help prevent leaks by keeping out dirt and moisture.

6-46 Check Tire Pressure System (If Equipped)
The check tire pressure system can alert you to a large
change in the pressure of one tire. The system won't
alert you before you drive that a tire is low or flat.
You must begin driving before the system will
work properly.
The CHECK TIRE PRESSURE message will appear
on the Driver Information Center (DIC) if pressure
difference (low pressure) is detected in one tire.
The check tire pressure system may not alert you if:

more than one tire is low,

the vehicle is moving faster than 65 mph (105 km/h),

the system is not yet calibrated,

the tire treadwear is uneven,

the compact spare tire is installed,

tire chains are being used, or

the vehicle is being driven on a rough or frozen road.
If the anti
-lock brake system warning light comes on,
the check tire pressure system may not be working
properly. See your dealer for service. Also, see
ªAnti
-Lock Brake System Warning Lightº in the Index.The check tire pressure system detects differences
in tire rotation speeds that are caused by changes
in tire pressure. The system can alert you about a low
tire
-- but it doesn't replace normal tire maintenance.
See ªTiresº in the Index.
When the CHECK TIRE PRESSURE message appears
on the Driver Information Center, you should stop as
soon as you can and check all your tires for damage.
If a tire is flat, see ªIf a Tire Goes Flatº in the Index.
Also check the tire pressure in all four tires as soon as
you can. See ªInflation
-Tire Pressureº in the Index.
Any time you adjust a tire's pressure or have one or
more tires repaired or replaced, you'll need to reset
(calibrate) the check tire pressure system. You'll also
need to reset the system whenever you rotate the tires,
buy new tires and install or remove the compact spare.
Don't reset the check tire pressure system without first
correcting the cause of the problem and checking and
adjusting the pressure in all four tires. If you reset the
system when the tire pressures are incorrect, the check
tire pressure system will not work properly and may not
alert you when a tire is low or high.

6-47
To reset (calibrate) the system:
1. Turn the ignition switch to RUN.
2. Press the GAGE INFO button on the DIC until
TIRE PRESSURE appears on the display.
3. Press and hold the DIC RESET button for about
five seconds. After five seconds, the display will
show TIRE PRESSURE RESET. If TIRE
PRESSURE RESET does not appear in the display
after about five seconds retry the process. If it does
not work after two tries, see your dealer for service.
After you release the DIC RESET button, TIRE
PRESSURE NORMAL will appear in the display.
The system completes the calibration process during
driving. Calibration time can take 45 to 90 minutes,
depending on your driving habits. After the system
has been calibrated, the system will alert the driver
that a tire is low, up to a maximum speed of
65 mph (105 km/h).Tire Inspection and Rotation
Tires should be rotated every 6,000 to 8,000 miles
(10 000 to 13 000 km). Any time you notice unusual
wear, rotate your tires as soon as possible and check
wheel alignment. Also check for damaged tires or
wheels. See ªWhen It's Time for New Tiresº
and ªWheel Replacementº later in this section for
more information.
The purpose of regular rotation is to achieve more
uniform wear for all tires on the vehicle. The first
rotation is the most important. See ªScheduled
Maintenance Servicesº in the Index for scheduled
rotation intervals.
When rotating your tires, always use the correct rotation
pattern shown here.

6-48
Don't include the compact spare tire in your
tire rotation.
After the tires have been rotated, adjust the front and
rear inflation pressures as shown on the Tire
-Loading
Information label. Reset the Check Tire Pressure
System. See ªCheck Tire Pressure Systemº in the Index.
Make certain that all wheel nuts are properly tightened.
See ªWheel Nut Torqueº in the Index.
CAUTION:
Rust or dirt on a wheel, or on the parts to which
it is fastened, can make wheel nuts become loose
after a time. The wheel could come off and cause
an accident. When you change a wheel, remove
any rust or dirt from places where the wheel
attaches to the vehicle. In an emergency, you can
use a cloth or a paper towel to do this; but be
sure to use a scraper or wire brush later, if you
need to, to get all the rust or dirt off. See
ªChanging a Flat Tireº in the Index.
When It's Time for New Tires
One way to tell when it's
time for new tires is to
check the treadwear
indicators, which will
appear when your tires have
only 1/16 inch (1.6 mm) or
less of tread remaining.
You need a new tire if any of the following statements
are true:

You can see the indicators at three or more places
around the tire.

You can see cord or fabric showing through the
tire's rubber.

The tread or sidewall is cracked, cut or snagged deep
enough to show cord or fabric.

The tire has a bump, bulge or split.

The tire has a puncture, cut or other damage that
can't be repaired well because of the size or location
of the damage.

6-49 Buying New Tires
To find out what kind and size of tires you need, look at
the Tire
-Loading Information label.
The tires installed on your vehicle when it was new had
a Tire Performance Criteria Specification (TPC Spec)
number on each tire's sidewall. When you get new tires,
get ones 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,
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 ªMSº
(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,
though. It was developed for use on your vehicle.
CAUTION:
If you use bias-ply tires on your vehicle, the
wheel rim flanges 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.

6-50 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 specified government test course.
For example, a tire graded 150 would wear one and
a half (1 1/2) 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 significantly 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 specified 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.

6-51
Temperature -- A, B, C
The temperature grades are A (the highest), B, and C,
representing the tire's resistance to the generation of
heat and its ability to dissipate heat when tested under
controlled conditions on a specified indoor laboratory
test wheel. Sustained high temperature can cause the
material of the tire to degenerate and reduce tire life,
and excessive temperature can lead to sudden tire
failure. The grade C corresponds to a level of
performance which all passenger car tires must meet
under the Federal Motor Vehicle Safety Standard
No. 109. Grades B and A represent higher levels of
performance on the laboratory test wheel than the
minimum required by law.
Warning: The temperature grade for this tire is
established for a tire that is properly inflated and
not overloaded. Excessive speed, underinflation, or
excessive loading, either separately or in combination,
can cause heat buildup and possible tire failure.Wheel Alignment and Tire Balance
The wheels on your vehicle were aligned and balanced
carefully at the factory to give you the longest tire life
and best overall performance.
Scheduled wheel alignment and wheel balancing are
not needed. However, if you notice unusual tire wear or
your vehicle pulling one way or the other, the alignment
may need to be reset. If you notice your vehicle
vibrating when driving on a smooth road, your wheels
may need to be rebalanced.
Wheel Replacement
Replace any wheel that is bent, cracked, or badly
rusted or corroded. If wheel nuts keep coming loose,
the wheel, wheel bolts and wheel nuts should be
replaced. If the wheel leaks air, replace it (except some
aluminum wheels, which can sometimes be repaired).
See your dealer if any of these conditions exist.
Your dealer will know the kind of wheel you need.
Each new wheel should have the same load
-carrying
capacity, diameter, width, offset and be mounted the
same way as the one it replaces.