brakes GMC SIERRA 1993 Owner's Manual

AM48001 7
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; 0°C) 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 ability
to make a hard stop on a slippery
road. Even though you have the anti-lock braking system, you’\
ll want to begin
stopping sooner than you would on dry pavement. See “Anti-lo\
ck‘’ in the Index.
Allow greater following distance on any slippery road.
Watch for slippery spots. The road might be fine until you hi\
t 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.
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AM480043
Run your engine only as long as you musk. This saves fuel. When you run
the engine, make it go a little faster than just idle. That is, push the
accelerator slightly. This uses less fuel for the heat that yo\
u get and
it keeps
the battery (or batteries) charged. You will need a well-charged battery (or
batteries) to restart the' vehicle, and possibly for signaling later on with your
headlights. Let the heater run for awhile.
If you 'have a diesel engine, you
may have to run it at a higher speed
to lget enough heat. Then, shut the
engine
off and close the window almost all the way to preserve the heat.
Start the engine again and repeat this only when you feel really
uncomfortable from the cold. But
do it as little as'possible. Preserve the fuel
as long as you can.
To help keep warm, you can get out of the vehicle and
do some fairly vigorous exercises every half hour or so until help comes.
If You're Stuck in Deep Snow
This manual explains how to get the vehicle out of deep snow without
damaging it. See "Rocking Your Vehicle" in the Index.
Towing a mailer
CAUTION I
If you don't use the correct equipment and drive properly, you ca\
n
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.
I
i'- ." "
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Your Driving and the Road
Total Weight on Your Vehicle’s Tires
Be sure your vehicle’s tires are inflated to the limit for cold tires. You’ll find
these numbers on the Certification label at the rear edge of the driver’s door
(or see “Tire Loading” in the Index). Then be sure you don’t go over the
GVW limit for your vehicle.
Hitches
It’s important to have the correct hitch equipment. Crosswinds, large trucks
going by, and rough roads are a few reasons why you’ll need the righ\
t hitch.
Here are some rules
to follow:
If your vehicle has a step bumper and you are going to use a ball-type
hitch, remove the pad and cut holes in
it to match the hitch and safety
chain holes in the bumper.
If you’ll be pulling a trailer that, when loaded, will weigh more than 4,000
pounds (1800 kg) be sure to use a properly mounted weight-distributing
hitch and sway control of the proper size. This equipment is very
important for proper vehicle loading and good handling when you\
’re
driving.
Safety Chains
You should always attach chains between your vehicle and your trail\
er. Cross
the safety chains under the tongue of the trailer
so that the tongue will not
drop
to the road if it becomes separated from the hitch. Instructions about
safety chains may be provided by the hitch manufacturer
or by the trailer
manufacturer. Follow the manufacturer’s recommendation for atta\
ching safety
chains. Always leave just enough slack
so you can turn with your rig. And,
never allow safety chains to drag .on the ground.
Trailer Brakes
If your trailer weighs more than 1,000 pounds (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.
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~~) of fluid from your vehicles master cylinder.
If it does, both braking systems won’t work well. You could even lose your
brakes.
Will the trailer brake parts take 3,000 psi (20 650 kPa) of pressure? If
not, the trailer brake system must not be used with your vehi\
cle.
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.
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Driving with a Trailer
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
so responsive as your vehicle is by itself.
Before you start, check the trailer hitch and platform, safety \
chains, electrical
connector, lights, 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 lights and any trailer brakes are still working.
Following Distance
Stay at least twice as far behind the vehicle ahead as you w\
ould 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 g\
o 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 left, just move your 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.
Making Turns
When you’re turning with a trailer, make wider turns than normal. Do this so
your trailer wheels won’t strike soft shoulders, curbs, road signs\
, trees, or
other objects. Avoid jerky or sudden maneuvers. Signal well in advance.
Turn Signals When Towing a Trailer
When you tow a trailer, your vehicle has to have a different turn signal
flasher and extra wiring. The green arrows on your instrument \
panel will flash
whenever you signal a turn or lane change. Properly hooked up, the trailer
lights will also flash, telling other drivers you’re about t\
o turn, change lanes,
or stop.
When towing a trailer, the green arrows on your instrument pan\
el will flash for
turns even
if the bulbs on the trailer are burned out. Thus, you may think
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Your Driving and the Road
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 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
45 mph (70
kmlh) or less to reduce the possibility of engine and transmission overheating.
IT you have an automatic transmission, you should use D (or, as you need to,
a lower gear) when towing a trailer. Operating your vehicle i\
n
D when towing
a trailer will minimize heat buildup and extend the life of your transmission.
Or, if you have a manual transmission with fifth gear and you are towing a
trailer, it’s better not to use fifth gear. Just drive in fourth gear
(or, as you
need to, a lower gear).
Parking on Hills
You really 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 P (Park) yet, or into gear
2. Have someone place chocks under the trailer wheels.
for a manual transmission.
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 \
then
5. If you have a four-wheel-drive vehicle, be sure the transfer case is in a
6. Release the regular brakes.
shift
to
P (Park), or R (Reverse) for a manual transmission.
drive gear-not in
N (Neutral).
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CAUTION
It can be dangerous to get out of your vehicle if the shift lever is not
fully in
P (Park) with the parking brake firmly set. Your vehicle can
roll.
If you have left the engine running, the vehicle can move suddenl\
y.
You
or others could be injured. To be sure your vehicle won’t move,
when you’re on fairly level ground, use the steps that follow.
If you have four-wheel drive and your transfer case is in N (Neutral),
your vehicle will be free to
roll, even if your shift lever is in P (Park).
So, be sure the transfer case is in a drive gear-not in N (Neutral).
If you are parking on a hill, or if you’re pulling a trailer, also see
“Parking On Hills” in the Index.
When You Are Ready to Leave After Parklng on a Hill
1. Apply your regular brakes and hold the pedal down while you:
Start your engine;
Shift into a gear; and
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 To wing
Your vehicle will need service more often when you’re pulling a trailer. See
the Maintenance Schedule for more on this. Things that are esp\
ecially
important in trailer operation are automatic transmission fluid (don’t overfill),
engine oil, axle lubricant, belts, cooling system, and brake ad\
justment. 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.
mailer Wiring Harness
See “Trailer Wiring Harness’’ in the Index.
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Your Driving and the Road
Power Winches
i !
If you wish to use a power winch on your vehicle, only use it \
when your
vehicle is stationary or anchored.
i
NOTICE
Use the regular brakes, set the parking brake or block the wh\
eels to keep
your vehicle from rolling.
Power rake-off (PTO)
Before using a power take-off, refer to the manufacturer’s or installer’s
instructions.
To engage a power take-off:
1. Set ths parking brake.
2. Shift the transmission into N (Neutral).
3. Hold the clutch pedal down and engage the power take-off.
*
If you are going to drive the vehicle, shift the transmission int\
o the gear
you want. Then shift the transfer case into the range you wan\
t
(if you
have four-wheel-drive), apply the regular brakes and release th\
e parking
brake.
When you release the clutch, the power take-off will start.
4. Release the clutch (and the regular brakes) as you normally \
would.
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Using a Transfer Case Mounted Power Take-Off (Manual
Transmission)
1. Set the parking brake.
2. Shift the transfer case into N (Neutral).
3. Hold the clutch pedal down. If the vehicle will remain in the same place,
4. Engage the power take-off.
shift the transmission into the highest
gear.
If you are going to drive the vehicle, shift the transmission into the gear
you want. Then shift the transfer case into the range you wan\
t, apply
the regular brakes and release the parking brake.
5 Release the clutch (and the regular brakes) as you normally \
would.
Using a Transfer Case Mounted Power Take-Off (Automatic
Transmission)
When you release the clutch, the power take-off will start.
1 I Set the parking brake.
2. Shift the transfer case into N (Neutral).
3. Shift the transmission into N (Neutral).
4. Engage the power take-off.
If you are going to drive the vehicle, shift the transfer case into the
range you want. Then apply the regular brakes and release the \
parking
brake.
5. Shift the transmission to D (Drive) to start the power take-off.
6. Release the regular brakes to drive the vehicle.
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Brake Master Cylinder
Your brake master cylinder is here. It is filled with DOT-3 brake fluid.
K2470
There are only two reasons why the brake fluid level in your \
master cylinder
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.
CAUTION I
If you have too much brake fluid, it can spill on the engine. The fluid
and your vehicle could be damaged. Add
. ake fhid nnlv en wn
is done on the brake hydraulic system.
- will burn if the engine is hot enough. You or others could he burned
Refer
to the Maintenance Schedule to determine when to check your brake
fluid. See “Periodic Maintenance” in the index.
To Check Brake Fluid:
You can check the brake fluid without taking off the cap. Just look at the
windows on the brake fluid reservoir. The fluid levels should be above the
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Service & Appearance Care
MIN mark. If they aren’t, have your brake system checked to see if there is a
leak.
t
After work is done on the brake hydraulic system, make sure t\
he levels are
above
MIN and below the top of each window.
What To Add:
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.
Hydro-Boost Brake System (Hydraulic Pump)
The power steering pump is also used as the Hydro-boost pump. Refer to
“Power Steering System” in this section when checking fluid level or adding
fluid.
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.
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