brake CHEVROLET ASTRO 1996 Service Manual

Checking Brake Fluid What to Add
x
You
can check the brake fluid without taking off the cap.
Just look at the window
on 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 MIN and below the top of
the window. When
you do
need brake fluid, use only DOT-3 brake
fluid
-- such as Delco Supreme 11 @ (GM Part
No. 1052535).
Use new brake fluid from a sealed
container only, and always clean the brake fluid
reservoir
ca. lefore removing it. *
A 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.
6-33

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.
I A CAUTION:
The brake wear warning sound means that
sooner or later 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.
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). 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.
Free movement
of brake calipers and properly torqued
wheel nuts are necessary to help prevent brake
pulsation. When tires are rotated, inspect brake calipers
for movement, brake pads for wear, and evenly torque
wheel nuts
in the proper sequence to GM specifications.
6-34

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. 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 brakes replaced, have the rear brakes inspected, too.
Brake linings should always be replaced as complete
axle sets.
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 modern 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.
Vehicles we design and test have top-quality
GM brake
parts
in them, as your vehicle does when it is new. 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 genuine 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
Every new vehicle has a Delco Freedom@ battery. You
never have
to add water to one of these. When it’s time
for a new battery, we recommend a Delco Freedom
battery. Get one that has the replacement number shown
on
the original battery’s label.
6-35

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 model.
~ -.
’
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 whee1,’wheel bolts and wheel nuts
for replacement.
-- I--
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” in the Index for
more information.
Used Replacement Wheels
A
/! CAUTION: ..
I
Putting a used wheel on your vehicle is
dangerous. You can’t know how
it’s been used or
how many miles 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.
6-48

15
16
', 17
18
19
Fuse/Circuit Usage Breaker
14 Cluster HVAC Controls, Chime
Module, Radio Illumination, Rear Heat
Switch Illumination, Rear
WiperNasher Switch Illumination,
Rear Liftgate Switch Illumination, Remote Cassette Illumination,
OH Console
DRL Lamps
Front Turn Signals, Rear Turn Signals,
Trailer Turn Signals, Back-up Lamps,
BTSI Solenoid
Radio: ATC (Standby), 2000 Series
(Main Feed), Rear Seat Audio Controls
VCM-Ign 3, VCM- Brake, 4WAL,
Cruise Stepper Motor
Radio: ATC (Main Feed),
2000 Series (Standby)
A
B
Fuse/Circuit Usage
Breaker
20 PRNDLI Odometer, TCC Enable and
PWM Solenoids, Shift
A and Shift B
Solenoids, 3-2 Downshift Solenoids
Not Used
Not Used Rear Wiper, Rear Washer Pump
Not Used
(Circuit Breaker) Power Door Lock,
6-way Power Seat, Keyless Entry
Module, Dutch Door Module, Dutch
Door Release
(Circuit Breaker) Power Windows
21
22
23
24
6-63

Fuse
UPFIT-BATT .......
UPFIT-IGN . .
Spare .....
Fuse Puller*
Spare
.............
Spare .............
ECM-B ............
..
..
HORN ......
A/C COMP ...
RR DEFOG .......
ENG-I ......
IGN-E
..
..
Usage
Upfitter Battery
Power Stud, Trailer Wiring
Harness Upfitter Ignition Relay
Not Used
Not Used Not Used
Fuel Pump Relay,
VCM, Oil Pressure
Switch/Sender
Horn Relay
A/C Enable Relay
Heater-A/C Control Selector Switch
Oxygen Sensors 1-4,
Camshaft Position Sensor,
Mass Air Flow Sensor,
Evaporative Emission
Canister Purge Solenoid
Valve, Linear EGR Valve
Solenoid, VCM
A/C Enable Relay
Fuse
ECM-I ..... .....
LIGHTING .....
BATT I/P .......
IGN A .............
IGN B .............
ABS ..............
AIC ...............
RR HTR/AC ........
Spare .............
Usage
Fuel Injectors 1-6,
Crankshaft Position Sensor,
VCM, Distributor Ignition
Control Module Park Lamps Fuse,
DRL Fuse, Headlamp and
Panel Dimmer Switch
Fuse Block Fuses,
Power Seat CB,
Stop/Hazard Fuse,
Auxiliary Power Fuse,
Cigarette Lighter Fuse,
Radio, Battery Fuse
Starter Relay, Ignition Switch
Ignition Switch
Brake Pressure Module Valve Blower Motor Resistor,
Blower Relay
Auxiliary Heater A/C Relay
Not Used
* A fuse puller is included in the underhood electrical
center. You
will also find spare fuses.
6-65

Maintenance Schedule
Short TripKity Definition
Follow the Short TripKity Maintenance Schedule if any
one
of these conditions is true for your vehicle:
0
0
0
0
0
Most trips are less than 5 to 10 miles (8 to 16 km).
This is particularly important when outside
temperatures are below freezing.
Most trips include extensive idling (such
as frequent
driving in stop-and-go traffic).
Most trips are through dusty areas.
You frequently tow a trailer or use a carrier on top of
your vehicle.
If the vehicle is used for delivery service, police, taxi
or other commercial application.
One of the reasons yo~l should follow this schedule if
you operate your vehicle under any of these conditions
is
that these conditions cause engine oil to break
down soonex
Short Trip/City Intervals
Every 3,000 Miles (5 000 km): Engine Oil and Filter
Change (or
3 months, whichever occurs first). Chassis
Lubrication (or
3 months, whichever occurs first). Drive
Axle Service (or
3 months, whichever occurs fust).
At 6,000 Miles (10 000 km) -- Then Every
12,000 Miles
(20 000 km): Tire Rotation.
Every 15,000 Miles (25 000 km): Air Cleaner Filter
Inspection,
if driving in dusty conditions. Front
Wheel Bearing Repack (2WD only) (or at each brake
relining, whichever occurs first). Automatic
Transmission Service (severe conditions only).
Every 30,000 Miles (50 000 km): Air Cleaner Filter
Replacement.
Fuel Filter Replacement. Automatic
Transmission Service (Normal Conditions).
Every 60,000 Miles (100 000 km): Engine Accessory
Drive Belt Inspection. Fuel
Tank, Cap and Lines Inspection.
Every 100,000 Miles (166 000 km): Cooling System
Service (or every
60 months, whichever occurs first).
Spark Plug Wire Inspection. Spark Plug Replacement.
Positive Crankcase Ventilation (PCV) Valve Inspection.
These intervals only summarize nzaintenance services.
Be sure to follow the complete maintenance schedule on
the following pages.
7-4

Maintenance Schedule
Long Tripmighway Definition Long Trip/Highway Intervals
Follow this maintenance schedule only if none of the
conditions from the Short Trip/City Maintenance
Schedule is true.
Driving a vehicle with nf.lly warmed engine under
highway conditions causes engine oil to break
down sloweE
Every 7,500 Miles (12 500 km): Engine Oil and Filter
Char,ge (or every 12 months, whichever occurs first).
Chassis Lubrication (or every 12 months, whichever
occurs first). Drive Axle Service.
At 7,500 Miles (12 500 km) -- Then Every
15,000 Miles
(25 000 km): Tire Rotation.
Every 15,000 Miles (25 000 km): Automatic
Transmission Service (severe conditions only).
Every 30,000 Miles (50 000 km): Fuel Filter
Replacement. Air Cleaner Filter Replacement. Front
Wheel Bearing Repack (2WD only)
(or at each brake
relining, whichever occurs first). Automatic
Transmission Service (Normal Conditions).
Accessory Drive Belt Inspection.
Fuel Tank,
Cap and Lines Inspection.
Every 100,000 Miles (166 000 km): Cooling System
Service (or every
60 months, whichever occurs first).
Spark Plug Wire Inspection. Spark Plug Replacement.
Positive Crankcase Ventilation (PCV) Valve Inspection.
These intervals only swnnzarize maintenance services.
Be sure to
follow the complete maintenance schedule on
the following pages.
Every 60,000 Miles (100 000 km): Engine
7-5

Short Trip/City Maintenance Schedule
The services shown in this schedule up to 100,000 miles
(166
000 km) should be performed after 100,000 miles
(166
000 km) at the same intervals.
Footnotes
3- The U.S. Environmental Protection Agency or the
California Air Resources Board has determined that the
failure
to perform this maintenance item will not nullify
the emission warranty or limit recall liability prior
to the
completion
of the vehicle’s useful life. We, however,
urge that all recommended maintenance services be
performed at the indicated intervals and the maintenance
be recorded.
# Lubricate the front suspension, ball joints and
kingpin bushings, steering linkage and transfer case
shift linkage, parking brake cable guides and brake
pedal springs. Drive
a
a
a
a
lxle service:
Locking Differential
-- Drain fluid and refill at first
engine oil change. At subsequent oil changes, check
fluid level and add fluid as needed. If driving in
dusty areas or towing a trailer, drain fluid and refill
every
15,000 miles (25 000 km).
Standard Differential
-- Check fluid level and add
fluid as needed
at every oil change. If driving in
dusty areas or towing a trailer, drain fluid and refill
every
15,000 miles (25 000 km).
More frequent lubrication may be required for
heavy-duty use.
7-6

I Short TripKity Maintenance Schedule I
3,000 Miles (5 000 km)
0 Change engine oil and filter (or every
3 months, whichever occurs first).
0 Lubricate chassis components; see
An Emission Control Service.
footnote ## (or every 3 months, whichever
occurs first).
0 Check readfront axle fluid level and add
fluid
as needed. Check constant velocity
joints and axle seals
for leaking. **
I DATE I ACTUAL MILEAGE I SERVICED BY I J
6,000 Miles (10 000 km)
0 Change engine oil and filter (or every
3 months, whichever occurs first).
An Emission Control Service.
0 Lubricate chassis components; see footnote #
(or every 3 months, whichever occurs first).
0 Check readfront axle fluid level and add fluid
as needed. Check constant velocity joints and
axle seals for leaking.
**
0 Rotate tires. See “Tire Inspection and Rotation”
in the Index for proper rotation pattern and
additional information. During tire rotation,
check brake calipers for freedom of movement.
Refer to the appropriate
GM service manual for
proper caliper service procedures.
DATE SERVICED BY: ACTUAL MILEAGE
~~~ ~~ ~.. ~.
7-7