brakes CHEVROLET ASTRO 1996 User Guide

Loss of Control
Let’s review what driving experts say about what
happens when the three control systems (brakes, steering
and acceleration) don’t have enough friction where the
tires meet the road
to do what the driver has asked.
In
any emergency, don’t give up. Keep trying to
steer and constantly seek an escape route or area of
less danger.
Skidding
In a skid, a driver can lose control of the vehicle.
Defensive drivers avoid most skids by taking
reasonable care suited to existing conditions, and by
not “overdriving” those conditions. But skids are
always possible.
The three types
of skids correspond to your vehicle’s
three control systems. In the braking skid, your wheels
aren’t rolling. In
the steering or cornering skid, too
muchspeed or steering
in a curve causes tires to slip and
lose cornering force. And in the acceleration skid, too
much throttle causes the driving wheels
to spin.
A cornering skid and an acceleration skid are best
handled by easing your foot off the accelerator pedal.
If your vehicle starts to slide, ease your foot off the
accelerator pedal and quickly steer the way
you want the
vehicle
to go. If you start steering quickly enough, your
vehicle may straighten out. Always be ready for a
second skid
if it occurs.
Of course, traction is reduced when water, snow, ice,
gravel or other material is on the road. For safety,
you’ll
want to slow down and adjust your driving to these
conditions. It is important to slow down
on slippery
surfaces because stopping distance will be longer and
vehicle control more limited.
While driving on a surface with reduced traction, try
your best to avoid sudden steering, acceleration or
braking (including engine braking by shifting
to a lower
gear).
Any sudden changes could cause the tires to slide.
You may not realize the surface is slippery until your
vehicle is skidding. Learn to recognize warning clues
--
such as enough water, ice or packed snow on the road to
make a “mirrored surface”
-- and slow down when you
have any doubt.
Remember: Any anti-lock brake system (ABS) helps
avoid only
the braking skid.
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The heavier the rain, the harder it is to see. Even if your
windshield wiper blades are
in good shape, a heavy rain
can make
it harder to see road signs and traffic signals,
pavement markings,
the edge of the road and even
people walking.
It’s wise to keep
your wiping equipment in good shape
and keep your windshield washer tank filled
with
washer fluid. Replace your windshield wiper inserts
when they show signs
of streaking or missing areas on
the windshield, or when strips of rubber start to separate
from the inserts. Driving too fast through large water puddles
or
even
going through some car washes can cause problems, too.
The water may affect your brakes. Try to avoid puddles.
But if you can’t, try to slow down before you hit them.
Wet brakes can cause accidents. They won’t work
well in a quick stop and may cause pulling to one
side.
You could lose control of the vehicle.
After driving through a large puddle of water or
a car wash, apply your brake pedal lightly until
your brakes work normally.
49.1 5

If you drive regularly in steep country, or if you’re
planning to visit there, here are some tips that can make
your trips safer and more enjoyable.
0 Keep your vehicle in good shape. Check all fluid
. levels and also the brakes, tires, cooling system and
transmission. These parts can work hard
on
mountain roads.
0 Know how to go down hills. The most important
thing to know is this: let your engine do some
of the
slowing down. Shift to
a lower gear when you go
down a steep or long hill.
~~~
A CAUTION:
If you don’t shift down, your brakes could get
so hot that they wouldn’t work well. You would
then have poor braking
or even none going
down
a hill. You could crash. Shift down to let
your engine assist your brakes on
a steep
downhill slope. Coas ,g
downhill in
NEUTRAL (N) or with the
ignition
off is dangerous. Your brakes will have to
do
all the work of slowing down. They could get so
hot that they wouldn’t work well. You would then
have poor braking or even none going down
a hill.
You could crash. Always have your engine running
and your vehicle in gear when you go downhill.
0 Know how to go uphill. You may want to shift down
to a lower gear. The lower gears help cool your engine and transmission, and you can climb the hill better.
0 Stay in your own lane when driving on two-lane
roads
in hills or mountains. Don’t swing wide or cut
across the center
of the road. Drive at speeds that let
you stay
in your own lane.
0 As you go over the top of a hill, be alert. There could be
something in your lane, like a stalled car or an accident.
0 You may see highway signs on mountains that warn of
special problems. Examples are long grades, passing or
no-passing zones, a falling rocks area
or winding
roads. Be alert
to these and take appropriate action.
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What’s the worst time for this? “Wet ice.” Very cold
snow or
ice can be slick and hard to drive on. But wet
ice can be even more trouble because
it may offer the
least traction
of all. You can get wet ice when it’s about
freezing
(32°F; OOC) and freezing rain begins to fall.
Try
to avoid driving on wet ice until salt and sand crews
can get there. Whatever
the condition -- smooth ice,
packed, blowing
or loose snow
-- drive with caution.
Accelerate gently. Try
not to break the fragile traction. If
you accelerate too fast, the drive wheels will spin and
polish the surface under the tires even more.
Your anti-lock brakes improve your vehicle’s stability
when
you make a hard stop on a slippery road. Even
though
you have an anti-lock braking system, you’ll
want to begin stopping sooner than
you would on dry
pavement. See “Anti-Lock”
in the Index.
Allow greater following distance on any slippery road.
Watch for slippery spots. The road might be fine
until you hit a spot that’s covered with ice. On an
otherwise clear road, ice patches may appear
in
shaded areas where the sun can’t reach: around
clumps of trees, behind buildings or under bridges.
Sometimes the surface of a curve or an overpass may
remain icy when the surrounding roads are clear.
If
you see a patch of ice ahead of you, brake before you
are on
it. Try not to brake while you’re actually on
the ice, and avoid sudden steering maneuvers.

Towing a Trailer
r
A CAUTION:
If you don’t use the correct equipment and drive
properly, you can lose control when you pull a
trailer. For example,
if the trailer is too heavy, the
brakes may not work well
-- or even at all. You
and your passengers could be seriously injured. Pull a trailer only
if you have followed all the
steps in this section.
Ask your GM dealer for
advice and information about towing a trailer
with your vehicle.
NOTICE:
Pulling a trailer improperly can damage your
vehicle and result in costly repairs not covered by
your warranty.
To pull a trailer correctly, follow
the advice in this part, and see your
GM dealer
for important information about towing a trailer with your vehicle.
Every vehicle is ready for some trailer towing.
If yours
was built with trailering options, as many are, it’s ready
for heavier trailers. But trailering is different than just
driving your vehicle by itself. Trailering means changes
in handling, durability and fuel economy. Successful,
safe trailering takes correct equipment, and it has
to be
used properly.
That’s the reason for this part. In it are many
time-tested, important trailering tips and safety rules.
Many
of these are important for your safety and that of
your passengers.
So please read this section carefully
before
you pull a trailer.
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Trailer Brakes
If your trailer weighs more than 1,000 lbs. (450 kg)
loaded, then it needs its own brakes
-- and they must be
adequate. Be sure
to read and follow the instructions for
the trailer brakes
so you’ll be able to install, adjust and
maintain them properly.
Your trailer brake system can tap into your vehicle’s
hydraulic brake system, except:
a
a
a
Don’t tap into your vehicle’s brake system if
the trailer’s brake system will use more than
0.02 cubic inch (0.3 cc) of fluid from your vehicle’s
master cylinder. If
it does, both braking systems
won’t work well.
You could even lose your brakes.
Will the trailer parts take
3,000 psi (20 650 kPa) of
pressure? If not, the trailer brake system must
not be
used with your vehicle.
If everything checks out this far, then make the brake
fluid tap at the port
on the master cylinder that sends ’
fluid to the rear brakes. But don’t use copper tubing
for this. If
you do, it will bend and finally break off.
Use steel brake tubing.
Driving with a Trailer
A CAUTION:
If you have a rear-most window open and you
pull
a trailer with your vehicle, carbon monoxide
(CO) could come into your vehicle. You can’t see
or smell CO. It can cause unconsciousness or
death. (See “Engine Exhaust” in the Index.)
To
maximize your safety when towing a trailer:
Have your exhaust system inspected for
leaks, and make necessary repairs before
starting on your trip.
Keep the rear-most windows closed.
If exhaust does come into your vehicle
through
a window in the rear or another
opening,
drive with your front, main
heating or cooling system
on and with the
fan on any speed. This will bring fresh,
outside air into your vehicle.
Do not use
MAX A/C because it only recirculates the
air inside your vehicle. (See “Comfort
Controls” in the Index.)
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Towing a trailer requires a certain amount of experience.
Before setting out for the open road,
you’ll want to get
to know your rig. Acquaint yourself with the
feel of
handling and braking with the added weight of
the
trailer. And always keep in mind that the vehicle you are
driving is now a good deal longer and not nearly as
responsive as your vehicle is by itself.
Before
you start, check the trailer hitch and platform
(and attachments), safety chains, electrical connector,
lamps, tires and mirror adjustment. If the trailer has
electric brakes, start your vehicle and trailer moving and
then apply the trailer brake controller by hand to be sure
the brakes are working. This lets you check your
electrical connection at the same time.
During your trip, check occasionally to be sure that the
load is secure, and that the lamps and any trailer brakes
are still working.
lowing Distance
>ray at least twice as far behind the vehicle ahead as you
would when driving your vehicle without a trailer. This
can help you avoid situations that require heavy braking
and sudden turns.
Passing
You’ll need more passing distance up ahead when
you’re towing
a trailer. And, because you’re a good deal
longer,
you’ll need to go much farther beyond the
passed vehicle before you can return to your lane.
Backing Up
Hold the bottom of the steering wheel with one hand.
Then, to move the trailer
to the left, just move that hand
to the left. To move the trailer to the right, move your
hand to the right. Always back up slowly and,
if
possible, have someone guide you.
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Making Turns
NOTICE:
Making very sharp turns while trailering could
cause the trailer to come in contact with the
vehicle. Your vehicle could
be damaged. Avoid
making very sharp turns while trailering.
When you’re turning with a trailer, make wider turns than
normal.
Do this so your trailer won’t strike soft shoulders,
curbs, road signs, trees or other objects. Avoid jerky or
sudden maneuvers. Signal well in advance.
Tbrn Signals When Towing a Trailer
When you tow a trailer, your vehicle has to have extra
wiring and a heavy-duty turn signal flasher (included
in
the optional trailering package).
The green arrows on your instrument panel will flash
whenever you signal a turn or lane change. Properly
hooked up, the trailer lamps will also flash, telling other
drivers you’re about to turn, change lanes or stop. When
towing
a trailer, the green arrows on your
instrument panel will flash for turns even if the bulbs
on
the trailer are burned out. Thus, you may think drivers
behind you are seeing your signal when they are not. It’s
important
to check occasionally to be sure the trailer
bulbs are still working.
Driving On Grades
Reduce speed and shift to a lower gear before you start
down a long or steep downgrade. If
you don’t shift
down, you might have to use your brakes
so much that
they would get hot and
no longer work well.
On a long uphill grade, shift down and reduce your
speed to around
45 mph (70 km/h) to reduce the
possibility
of engine and transmission overheating.
When towing at high altitude on steep uphill grades,
consider the following: Engine coolant will boil at a
lower temperature than at normal altitudes. If you turn
your engine off immediately after towing at high altitude
on steep uphill grades, your vehicle may show signs
similar to engine overheating.
To avoid this, let the
engine run while parked (preferably on level ground)
with the automatic transmission in
PARK (P) for a few
minutes before turning
the engine off. If you do get the
overheat warning, see “Engine Overheating” in
the Index.
4-35

Parking on Hills
Youereally should not park your vehicle, with a trailer
attached,
on a hill. If something goes wrong, your rig
could start to move. People can be injured, and both
your vehicle and the trailer can be damaged.
But
if you ever have to park your rig on a hill, here’s
how to do it:
1. Apply your regular brakes, but don’t shift into
PARK
(P) yet. Turn your wheels into the curb
when facing downhill and away from the curb when
facing uphill.
2. Have someone place chocks under the trailer wheels.
3, When the wheel chocks are in place, release the
regular brakes until the chocks absorb the load.
4. Reapply the regular brakes. Then apply your parking
brake, and shift to PARK
(P).
5. Release the regular brakes.
When You Are Ready to Leave After
Parking on a
Hill
1. Apply your regular brakes and hold the pedal down
while you:
Start your engine;
Shift into a gear; and
0 Release the parking brake.
2. Let up on the brake pedal.
3. Drive slowly until the trailer is clear of the chocks.
4. Stop and have someone pick up and store the chocks.
Maintenance When Trailer Towing
Your vehicle will need service more often when you’re
pulling a trailer. See the Maintenance Schedule for more
on this. Things that are especially important in trailer
operation are automatic transmission fluid (don’t
overfill), engine
oil, axle lubricant, belt, cooling system
and brake adjustment. Each
of these is covered in this
manual, and
the Index will help you find them quickly.
If you’re trailering, it’s a good idea
to review these
sections before you start your trip.
Check periodically
to see that all hitch nuts and bolts
are tight.
4-36

Brakes
Brake Fluid
Your.brake master cylinder reservoir is here. It is filled
with
DOT-3 brake fluid.
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 “top off’ 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.
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.
Refer to the Maintenance Schedule to determine when to
check your brake fluid. See “Periodic Maintenance
Inspections”
in the Index.
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