brake CHEVROLET ASTRO 2003 Service Manual

It I DU have toc ..Iuc.. >rake fluid, it can spill on
the engine. The fluid will burn if the engine is
hot enough. You or others could be burned,
and your vehicle could be damaged. Add brake
fluid 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 brake fluid. See
Part C: Periodic
Maintenance Inspections
on page 6-30.
Checking Brake Fluid
MIN / \
You can check the brake fluid without taking off the cap.
Just look at the brake fluid reservoir. The fluid 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.
5-43

Notice:
0 Using the wrong fluid 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 of fluid.
If you spill brake fluid on your vehicle’s painted
surfaces, the paint finish can be damaged.
Be careful not to spill brake fluid on your
vehicle. If you do, wash
it off immediately.
See “Appearance Care”
in the Index.
What to Add
When you do need brake fluid, use only DOT-3 brake
fluid. Use new brake fluid from a sealed container
only. See
Part D: Recommended Fluids and Lubricants
on page 6-32.
Always clean the brake fluid reservoir cap and the area
around the cap before removing it. This will help keep dirt
from enterinn the reservoir.
I
With the VI .-.. =I kir.- of flui, .n your b.,.re
system, your brakes may not work well, or they
may not even work at all. This could cause a
crash. Always use the proper brake fluid.
5-44

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 firmly).
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
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 first applied or lightly
applied. This does not mean something is wrong with
your brakes.
Properly torqued wheei nuts are necessary to heip
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.
Brake linings should always be replaced as complete
axle sets.
See
Brake System Inspection on page 6-31.
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.
5-45

Replacing Brake System Parts
Te 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. See
Engine Compartment Overview on
page 5-74 for battery location.
Warnings 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.
5-46

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 brake firmly on both vehicles involved
in the jump start procedure. Put an automatic
transmission in PARK (P) and a manual
transmission in NEUTRAL.
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter
or accessory power outlets. Turn off all lamps
that aren’t needed as well as radios. This will avoid
sparks and help save both batteries. In addition,
it could save your radio!
Nofice: If you leave your radio on, it could be badly
damaged. The repairs wouldn’t be covered by
your warranty.
4. Open the hoods and locate the batteries. Find the
positive
(+) and negative (-) terminals on each
battery.
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
flashlight if you need more light.
Be sure the battery has enough water.
You don’t need to add water to the ACDelco@
battery installed in your new vehicle. But if
a battery has filler caps, be sure the right amount
of fluid is there. If it is low, add water
to take care
of that first. If you don’t, explosive
gas could be present.
Battery fluid contains acid that can burn you.
Don’t get
it on you. If you accidentally get it in
your eyes or on your skin, flush the place with
water and get medical help immediately.
5-48

Wheel Alignment and Tire Balance If you need to replace any of your wheels, wheel bolts
or wheel nuts, replace them only with new
GM
The wheels on your vehicle were aligned and balanced original
equipment parts. This way, you will be sure to
carefully at the factory to give you the longest tire life have
the right wheel, wheel bolts and wheel nuts for
and best overall performance.
your
vehicle.
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. 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.
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
Changing a Flat Tire on page 5-71 for more
information.
-~
5-69

Used Replacement Wheels
Putting a uscu 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 a crash. If you have to replace a
wheel, use a new
GM original equipment wheel.
Tire Chains
Notice: Use tire chains only where legal and only
when you must. Use only
SAE Class ”S” type chains
that are the proper size for your tires. Install them on the rear axle tires 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.
If a Tire Goes Flat
It’s unusual for a tire to “blow out” while you’re driving,
especially
if you maintain your tires properly. If air
goes out of a tire, it’s much more likely to leak out
slowly. But
if you should ever have a “blowout”, here are
a few tips about what to expect and what to do:
If a front tire fails, the flat tire will create a drag that
pulls the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
A rear blowout, particularly on a curve, acts much like a
skid and may require the same correction you’d use
in a skid. In any rear blowout, remove your foot from the
accelerator pedal. Get the vehicle under control by
steering the way you want the vehicle to go. It may be
very bumpy and noisy, but you can still steer. Gently
brake to a stop
- well off the road if possible.
If a tire goes flat, the next part shows how to use your
jacking equipment to change a flat tire safely.
5-70

Changing a Flat Tire
If a tire goes flat, avoid further tire and wheel damage
by driving slowly to a level place. Turn on your hazard
warning flashers.
Changing a tire can cause an injury. The
vehicle can slip
off the jack and roll over you
or other people. You and they could be badly
injured. Find a level place to change your tire.
To help prevent the vehicle from moving:
1. Set the parking brake firmly.
2. Put the shift lever in PARK (P).
3. Turn off the engine.
4. Put the wheel blocks at the front and rear
of the tire farthest away from the one
being changed. That would be the tire
on the other side of the vehicle, at the
opposite end. The following steps will tell
you how to
use the jack
and change a tire.
5-7 1

12. Tighten the wheel nuts
firmly in a crisscross
sequence as shown.
Turn the ratchet
clockwise with the
UP mark facing you.
Incorrect wheel nuts or improperly tightened
wheel nuts can cause the wheel to come loose and even come
off. This could lead to an
accident. Be sure to use the correct wheel
nuts.
If you have to replace them, be sure to
get new
GM original equipment wheel nuts.
Stop somewhere as soon as you can and have
the nuts tightened with a torque wrench to the
proper torque specification. See “Capacities
and Specifications” in the Index for wheel
nut
torque specification.
Notice: Improperly tightened wheel nuts can lead
to brake pulsation and rotor damage. To avoid
expensive brake repairs, evenly tighten the wheel
nuts in the proper sequence and to the proper torque
specification. See “Capacities and Specifications”
in the index for the wheel nut torque specification.
13. Remove the wheel blocks.
Notice: Wheel covers won’t fit on your compact
spare.
If you try to put a wheel cover on your
compact spare, you could damage the cover or
the spare.
5-80

FuseKircuit Usage
Breaker
1
2
Stop/Turn/Hazard Lamps,
Center High Mounted Stop Lamp,
Anti-Lock Brakes
Radio Accy, Rear Seat
Audio Controls
FuseKircuit
Breaker
3
4
5
6
8
9
Usage
Courtesy Lamps, Glove Box Lamp,
Dome Reading Lamps, Vanity Mirror
Lamps, Courtesy Lamps
Daytime Running Lamps Relay,
Instrument Panel Cluster
Rear Defogger
Cruise Module, Truck Body Control Module, Instrument Panel Cluster,
Cruise Control Switch,
Electrochromic Mirror
Power Outlets, DLC,
Subwoofer Amplifier
Crank Circuit Fuse, ParWNeutral
Switch, Starter Enabler Relay
License Plate Lamp, Tailamps,
Parking Lamps, Ashtray Lamp,
Panel Lights, Trailer Taillamps,
Front and Rear Sidemarker Lamps,
Door Switch Illumination, Headlamp
Switch Illumination, Rear Seat
Audio Illumination, Truck Body
Control Module
5-94