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Some driving conditions or climates may cause a brake
squeal when the brakes are first 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 torque wheel nuts in the
proper sequence to GM specifications.
If you have rear drum brakes, they don't have wear
indicators, but if you ever hear a rear brake rubbing
noise, have the rear brake linings inspected immediately.
Also, the rear brake drums should be removed and
inspected each time the tires are removed for rotation or
changing. When you have the front brake pads replaced,
have the rear brakes inspected, too.
Brake linings should always be replaced as complete
axle sets.
See ªBrake System Inspectionº in Section 7 of
this manual under Part C ªPeriodic
Maintenance Inspections.º
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 make a brake stop, your disc brakes
adjust for wear.
If you don't have four
-wheel drive and your brake pedal
goes down farther than normal, your rear drum brakes
may need adjustment. Adjust them by backing up and
firmly applying the brakes a few times.
Replacing Brake System Parts
The braking system on a vehicle is complex. Its
many parts have to be of top quality and work well
together if the vehicle is to have really good braking.
Your vehicle was designed and tested with top
-quality
GM brake parts. When you replace parts of your braking
system
-- for example, when your brake linings wear
down and you have to have new ones put in
-- be sure
you get new approved GM replacement parts. If you
don't, your brakes may no longer work properly. For
example, if someone puts in brake linings that are wrong
for your vehicle, the balance between your front and
rear brakes can change
-- for the worse. The braking
performance you've come to expect can change in many
other ways if someone puts in the wrong replacement
brake parts.
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6-45 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 one of the correct
rotation patterns shown here.
If your vehicle has a compact spare tire, don't include it
in your tire rotation.
After the tires have been rotated, adjust the front and
rear inflation pressures as shown on the
Certification/Tire label. Make certain that all wheel nuts
are properly tightened. See ªWheel Nut Torqueº in
the Index.
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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.
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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.
Buying New Tires
To find out what kind and size of tires you need, look at
the Certification/Tire 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
(if you have one). 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.
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6-48 Uniform Tire Quality Grading
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.
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.
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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.
If you need to replace any of your wheels, wheel bolts
or wheel nuts, replace them only with new GM original
equipment parts. This way, you will be sure to have the
right wheel, wheel bolts and wheel nuts for your vehicle.
CAUTION:
Using the wrong replacement wheels, wheel bolts
or wheel nuts on your vehicle can be dangerous.
It could affect the braking and handling of your
vehicle, make your tires lose air and make you
lose control. You could have a collision in which
you or others could be injured. Always use the
correct wheel, wheel bolts and wheel nuts
for replacement.
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NOTICE:
The wrong wheel can also cause problems with
bearing life, brake cooling, speedometer or
odometer calibration, headlamp aim, bumper
height, vehicle ground clearance and tire or tire
chain clearance to the body and chassis.
See ªChanging a Flat Tireº in the Index for
more information.
Used Replacement Wheels
CAUTION:
Putting a used wheel on your vehicle is
dangerous. You can't know how it's been used or
how far it's been driven. It could fail suddenly
and cause an accident. If you have to replace a
wheel, use a new GM original equipment wheel.
Tire Chains
NOTICE:
If your vehicle has P235/75R15, P235/70R15,
P235/55R16 or 31x10.50R15LT/C size tires, don't
use tire chains. They can damage your vehicle
because there's not enough clearance.
Use another type of traction device only if its
manufacturer recommends it for use on your
vehicle and tire size combination and road
conditions. Follow that manufacturer's
instructions. To help avoid damage to your
vehicle, drive slowly, readjust or remove the
device if it's contacting your vehicle, and don't
spin your wheels.
NOTICE: (Continued)
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NOTICE: (Continued)
If you do find traction devices that will fit, install
them on the rear tires.
If you have other size tires, use tire chains only
where legal and only when you must. Use only
SAE Class ªSº type chains that are the proper
size for your tires. Install them on the drive axle
tires (four
-wheel-drive vehicles can use chains on
both axles) and tighten them as tightly as possible
with the ends securely fastened. Drive slowly and
follow the chain manufacturer's instructions. If
you can hear the chains contacting your vehicle,
stop and retighten them. If the contact continues,
slow down until it stops. Driving too fast or
spinning the wheels with chains on will damage
your vehicle.
Appearance Care
Remember, cleaning products can be hazardous. Some
are toxic. Others can burst into flame if you strike a
match or get them on a hot part of the vehicle. Some are
dangerous if you breathe their fumes in a closed space.
When you use anything from a container to clean your
vehicle, be sure to follow the manufacturer's warnings
and instructions. And always open your doors or
windows when you're cleaning the inside.
Never use these to clean your vehicle:
Gasoline
Benzene
Naphtha
Carbon Tetrachloride
Acetone
Paint Thinner
Turpentine
Lacquer Thinner
Nail Polish Remover
They can all be hazardous
-- some more than
others
-- and they can all damage your vehicle, too.