2003 GMC SONOMA Owner's Manual

Brakes
Brake Fluid
Your brake master cylinder reservoir isfilled with DOT-3
brakefluid. SeeEngine Compartment Overview on
page 5-10for the location of the reservoir.
There are only two reasons why the brakefluid level in
the reservoir might go down. Thefirst is that the
brakefluid goes down to an acceptable level during
normal brake lining wear. When new linings are put in,
thefluid level goes back up. The other reason is
thatfluid is leaking out of the brake system.If it is, you should have your brake systemfixed, since
a leak means that sooner or later your brakes won’t
work well, or won’t work at all.
So, it isn’t a good idea to“top off”your brakefluid.
Adding brakefluid won’t correct a leak. If you addfluid
when your linings are worn, then you’ll have too
muchfluid when you get new brake linings. You should
add (or remove) brakefluid, as necessary, only when
work is done on the brake hydraulic system.
{CAUTION:
If you have too much brakeuid, it can spill on
the engine. Theuid will burn if the engine is
hot enough. You or others could be burned,
and your vehicle could be damaged. Add brake
uid only when work is done on the brake
hydraulic system. See“Checking Brake Fluid”
in this section.
Refer to the Maintenance Schedule to determine when
to check your brakefluid. SeePart C: Periodic
Maintenance Inspections on page 6-31.
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Checking Brake Fluid
You can check the brakefluid without taking off the cap.
Just look at the brakefluid
reservoir. Thefluid level
should be above MIN.
If it isn’t have your brake
system checked to
see if there is a leak.
After work is done on the brake hydraulic system,
make sure the level is above the MIN but not over the
MAX mark.
What to Add
When you do need brakefluid, use only DOT-3 brake
fluid. Use new brakefluid from a sealed container
only. SeePart D: Recommended Fluids and Lubricants
on page 6-33.Always clean the brakefluid reservoir cap and the area
around the cap before removing it. This will help
keep dirt from entering the reservoir.
{CAUTION:
With the wrong kind ofuid in your brake
system, your brakes may not work well, or they
may not even work at all. This could cause a
crash. Always use the proper brakeuid.
Notice:
Using the wronguid can badly damage brake
system parts. For example, just a few drops of
mineral-based oil, such as engine oil, in your
brake system can damage brake system
parts so badly that they’ll have to be replaced.
Don’t let someone put in the wrong kind ofuid.
If you spill brakeuid on your vehicle’s painted
surfaces, the paintnish can be damaged. Be
careful not to spill brakeuid on your vehicle.
If you do, wash it off immediately. See
“Appearance Care”in the Index.
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Brake Wear
If you have four-wheel drive, your vehicle has four-wheel
disc brakes. If not, your vehicle has front disc brakes
and rear drum 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 pedalfirmly).
{CAUTION:
The brake wear warning sound means that
soon your brakes won’t 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 arefirst 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 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.
SeeBrake System Inspection on page 6-32.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 andfirmly applying the brakes a few times.
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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
need 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.
Battery
Your new vehicle comes with a maintenance free
ACDelco®battery. When it’s time for a new battery, get
one that has the replacement number shown on the
original battery’s label. We recommend an ACDelco
®
battery. SeeEngine Compartment Overview on
page 5-10for battery location.
Warning:Battery posts, terminals and related
accessories contain lead and lead compounds,
chemicals known to the State of California to cause
cancer and reproductive harm. Wash hands after
handling.
Vehicle Storage
If you’re not going to drive your vehicle for 25 days or
more, remove the black, negative (−) cable from
the battery. This will help keep your battery from
running down.
{CAUTION:
Batteries have acid that can burn you and gas
that can explode. You can be badly hurt if you
aren’t careful. See“Jump Starting”next for
tips on working around a battery without
getting hurt.
Contact your dealer to learn how to prepare your
vehicle for longer storage periods.
Also, for your audio system, seeTheft-Deterrent
Feature (Non-RDS Radios) on page 3-67or
Theft-Deterrent Feature (RDS Radios) on page 3-67.
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Jump Starting
If your battery has run down, you may want to use
another vehicle and some jumper cables to start your
vehicle. Be sure to follow the steps below to do it safely.
{CAUTION:
Batteries can hurt you. They can be dangerous
because:
They contain acid that can burn you.
They contain gas that can explode or
ignite.
They contain enough electricity to
burn you.
If you don’t follow these steps exactly, some
or all of these things can hurt you.
Notice:Ignoring these steps could result in costly
damage to your vehicle that wouldn’t be covered
by your warranty.
Trying to start your vehicle by pushing or pulling it
won’t work, and it could damage your vehicle.
1. Check the other vehicle. It must have a 12–volt
battery with a negative ground system.Notice:If the other system isn’t a 12-volt system
with a negative ground, both vehicles can be
damaged.
2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles aren’t touching
each other. If they are, it could cause a ground
connection you don’t want. You wouldn’t be able to
start your vehicle, and the bad grounding could
damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brakefirmly on both vehicles involved
in the jump start procedure. Put an automatic
transmission in PARK (P) or a manual transmission
in NEUTRAL before setting the parking brake. If
you have a four-wheel-drive vehicle, be sure
the transfer case is not in NEUTRAL (N).
Notice:If you leave your radio on, it could be badly
damaged. The repairs wouldn’t be covered by
your warranty.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or in the accessory power outlets. Turn off
the radio and all lamps that aren’t needed. This will
avoid sparks and help save both batteries. And it
could save your radio!
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4. Open the hoods and locate the batteries. Find the
positive (+) and negative (-) terminal locations on
each vehicle. SeeEngine Compartment Overview
on page 5-10for more information on location of
the battery.
{CAUTION:
Using a match near a battery can cause battery
gas to explode. People have been hurt doing
this, and some have been blinded. Use a
ashlight if you need more light.
Be sure the batteries have enough water.
You don’t need to add water to the ACDelco
®
battery (or batteries) installed in your new
vehicle. But if a battery hasller caps, be sure
the right amount ofuid is there. If it is low,
add water to take care of thatrst. If you don’t,
explosive gas could be present.
Batteryuid contains acid that can burn you.
Don’t get it on you. If you accidentally get it in
your eyes or on your skin,ush the place with
water and get medical help immediately.
{CAUTION:
Fans or other moving engine parts can injure
you badly. Keep your hands away from moving
parts once the engine is running.
5. Check that the jumper cables don’t have loose or
missing insulation. If they do, you could get a
shock. The vehicles could be damaged too.
Before you connect the cables, here are some
basic things you should know. Positive (+) will go
to positive (+) or to a remote positive (+) terminal
if the vehicle has one. Negative (-) will go to a
heavy, unpainted metal engine part or to a remote
negative (-) terminal if the vehicle has one.
Don’t connect positive (+) to negative (-) or you’ll
get a short that would damage the battery and
maybe other parts too. And don’t connect the
negative(-) cable to the negative (-) terminal on
the dead battery because this can cause sparks.
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6. Connect the red
positive (+) cable to the
positive (+) terminal
of the dead battery. Use
a remote positive (+)
terminal if the vehicle
has one.
7. Don’t let the other end
touch metal. Connect it to
the positive (+) terminal
of the good battery.
Use a remote positive (+)
terminal if the vehicle
has one.8. Now connect the black
negative (-) cable to the
negative (-) terminal
of the good battery. Use
a remote negative (-)
terminal if the vehicle
has one.
Don’t let the other end touch anything until the next
step. The other end of the negative (-) cabledoesn’t
go to the dead battery. It goes to a heavy, unpainted
metal engine part, or to a remote negative (-)
terminal on the vehicle with the dead battery.
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.
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10. Now start the vehicle with the good battery and run
the engine for awhile.
11. Try to start the vehicle that had the dead battery.
If it won’t start after a few tries, it probably needs
service.
Notice:Damage to your vehicle may result from
electrical shorting if jumper cables are removed
incorrectly. To prevent electrical shorting, take care
that the cables don’t touch each other or any
other metal. The repairs wouldn’t be covered by
your warranty.
A. Heavy, Unpainted Metal Engine Part
B. Good Battery
C. Dead Battery
To disconnect the jumper cables from both vehicles,
do the following:
1. Disconnect the black negative (-) cable from the
vehicle that had the dead battery.
2. Disconnect the black negative (-) cable from the
vehicle with the good battery.
3. Disconnect the red positive (+) cable from the
vehicle with the good battery.
4. Disconnect the red positive (+) cable from the
other vehicle.
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