brake CHEVROLET ASTRO 2002 Service Manual

6-11 Engine Compartment Overview
When you open the hood, this is what you will see:
A. Windshield Washer Fluid
B. Engine Coolant
C. Engine Oil DipstickD. Transmission Dipstick
E. Engine Air Cleaner/Filter
F. Engine Oil FillG. Brake Master Cylinder Reservoir
H. Power Steering Fluid Reservoir
I. Battery

6-23
Wait at least 30 minutes before checking the
transmission fluid level if you have been driving:

When outside temperatures are above 90F (32C).

At high speed for quite a while.

In heavy traffic
-- especially in hot weather.

While pulling a trailer.
To get the right reading, the fluid should be at normal
operating temperature, which is 180F to 200F
(82C to 93C).
Get the vehicle warmed up by driving about 15 miles
(24 km) when outside temperatures are above 50F
(10C). If it's colder than 50F (10C), drive the
vehicle in THIRD (3) until the engine temperature gage
moves and then remains steady for 10 minutes.
A cold fluid check can be made after the vehicle has
been sitting for eight hours or more with the engine off,
but this is used only as a reference. Let the engine run
at idle for five minutes if outside temperatures are
50F (10C) or more. If it's colder than 50F (10C), you may have to idle
the engine longer. Should the fluid level be low during
this cold check, you must check the fluid hot before
adding fluid. Checking the fluid hot will give you a
more accurate reading of the fluid level.
Checking the Fluid Level
Prepare your vehicle as follows:

Park your vehicle on a level place. Keep the
engine running.

With the parking brake applied, place the shift
lever in PARK (P).

With your foot on the brake pedal, move the shift
lever through each gear range, pausing for about
three seconds in each range. Then, position the
shift lever in PARK (P).

Let the engine run at idle for three minutes or more.

6-35
Brakes
Brake Fluid
Your brake master cylinder reservoir is filled with
DOT
-3 brake fluid. See ªEngine Compartment
Overviewº in the Index for the location of the reservoir.
There are only two reasons why the brake fluid level in
the reservoir might go down. The first is that the brake
fluid goes down to an acceptable level during normal
brake lining wear. When new linings are put in, the fluid
level goes back up. The other reason is that fluid is leaking out of the brake
system. If it is, you should have your brake system
fixed, 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 ªtop offº your brake fluid.
Adding brake fluid won't correct a leak. If you add fluid
when your linings are worn, then you'll have too much
fluid when you get new brake linings. You should add
(or remove) brake fluid, as necessary, only when work is
done on the brake hydraulic system.
CAUTION:
If you have too much brake 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 ªChecking Brake Fluidº in this section.
Refer to the Maintenance Schedule to determine when
to check your brake fluid. See ªPeriodic Maintenance
Inspectionsº in the Index.

6-36
Checking Brake Fluid
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.What to Add
When you do need brake fluid, use only DOT
-3 brake
fluid. Refer to ªRecommended Fluids and Lubricantsº
in the Index. Use new brake fluid from a sealed
container only.
Always clean the brake fluid 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 of fluid 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 brake fluid.

6-37
NOTICE:

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 ªAppearance Careº
in the Index.
Brake Wear
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 pedal firmly).
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.

6-38
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 tighten wheel nuts in the
proper sequence to GM torque specifications.
Your rear drum brakes 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 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
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.

6-54 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.
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.

6-68
Fuse/Circuit
BreakerUsage
1 Stop/Turn/Hazard Lamps,
Center High Mounted Stop
Lamp, Anti
-Lock Brakes
2 Radio Accy, RR Seat
Audio ControlsFuse/Circuit
BreakerUsage
3 Courtesy Lamps, Glove Box Lamp,
Dome Reading Lamps, Vanity
Mirror Lamps, Courtesy Lamps
4 Daytime Running Lamps Relay,
Instrument Panel Cluster
5 Rear Defogger
6 Cruise Module, TBC Module,
Instrument Panel Cluster,
Cruise Control Switch,
Electrochromic Mirror
7 Power Outlets, DLC,
Subwoofer Amplifier
8 Crank Circuit Fuse, Park/Neutral
Switch, Starter Enable Relay
9 License Plate Lamp, Taillamps,
Parking Lamps, Ashtray Lamp,
Panel Lights, Trailer Taillamps,
Front and Rear Sidemarker
Lamps, Door Switch Illumination,
Headlamp Switch Illumination,
Rear Seat Audio Illumination,
TBC Module

6-69
Fuse/Circuit
BreakerUsage
10 Air Bag System
11 Not Used
12 L, M1, M2 Blower Motor, Rear A/C
Relay Coil, Front Cont. Temp. Door
Motor, HI Blower Relay, Defogger
Timer Coil
13 Cigarette Lighter, Door Lock
Switches, Dutch Door Release
Module
14 Cluster Illum, HVAC Controls,
Chime Module, Radio Illumination,
Rear Heat Switch Illumination,
Rear Wiper/Washer Switch
Illumination, Rear Liftgate Switch
Illumination, Remote Cassette
Illumination, O/H Console,
TBC Illumination
15 TBC Module, Headlamp Relay
16 Front Turn Signals, Rear Turn
Signals, Trailer Turn Signals,
Back
-Up Lamps, BTSI SolenoidFuse/Circuit
BreakerUsage
17 Front Wipers, Front Washer Pump
18 VCM
-Ign 3, VCM-Brake, Cruise
Stepper Motor Signal, ATC Module
19 Instrument Panel Radio: ATC
(Main Feed), 2000 Series (Standby)
20 PRNDL/Odometer, TCC Enable
and PWM Solenoid, Shift A and
Shift B Solenoids, 3
-2 Downshift
Solenoid, Instrument Panel Cluster,
VCM Module
21 Pwr Adj Mirrors
22 Not Used
23 Rear Wiper, Rear Washer Pump
24 Not Used
A (Circuit Breaker) Power Door
Lock Relay, 6
-Way Power Seats
B (Circuit Breaker) Power Windows

6-72
Fuse/Circuit
BreakerUsage
DIODE
-1 A/C
Blank Not Used
Blank Not Used
Blank Not Used
LIGHTING Courtesy Fuse, Pwr. Adj. Mirrors
Fuse, TBC
-Battery Fuse
BATT Power ACCY CB, Stop/Hazard
Fuse, Auxiliary Power Fuse,
Cigarette Lighter Fuse,
Radio Battery Fuse
IGN A Starter Relay, Ignition Switch
IGN B Ignition Switch
ABS Electronic Brake
Control Module
Blank Not Used
RAP Radio Accy, Power Windows
HTD MIR/
RR DEFOGRear Window Defogger,
HVAC Control Head
Replacement Bulbs
Halogen Headlamps -
Sealed Beam2 H6054
Halogen Headlamps
-
Composite2 9006
(Low Beam)
Halogen Headlamps
-
Composite2 9005
(High Beam)
Parking, Turn Signal Lamps 23157NA
Rear, Stoplamps 22057
Sidemarker Lamps 4 194
Back
-Up Lamps2 1156
For any bulb not listed here, contact your dealer.