brakes GMC SIERRA 1994 Owner's Manual

If you are going to drive the vehicle, shift the transmission into th\
e gear
you want. Then shift the transfer case into the range you want, apply
the regular brakes and release the parking brake.
When you release the clutch, the power take-off will start.
5. Release the clutch (and the regular brakes) as you normally \
would.
Using a Transfer Case Mounted Power Take-Off
(Automatic Transmission)
1. 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 powe\
r take-off.
6. Release the regular brakes to drive the vehicle.
Towing a Trailer
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 section, and see your Veh\
icle
dealer for important information about towing a trailer with
your vehicle.
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from the front edge of the foot to the middle of the hitch ball socket. If
the distance is less than 12 inches, take the foot off the trailer tongue.
0 If you’ll be pulling a trailer that, when loaded, will weigh more than
4,000 pounds (1 8 14 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 trailer.
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
attaching 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.
Your trailer brake system can tap
into your vehicle’s hydraulic brake system,
but consider
the following:
0 Will the trailer brake system use more than 0.02 cubic inch (0.3 cc) of
fluid from your vehicle’s master cylinder? If it will, don’t tap into your
vehicle’s brake system. Both braking systems won’t work well, and
you
could even lose your brakes altogether.
0 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 vehicle.
If everything checks out this far, make the brake tap at the port on
the
master cylinder that sends the 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
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.
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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 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.
Making Turns
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.
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 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.
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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 with steep uphill grades,you need to consider
the following information. The lower atmospheric pressure at high altitude
allows your vehicles engine coolant to boil at a lower temperature than at
normal altitudes.
If you immediately turn your engine off after towing at high altitude with
steep uphill grades, your vehicle may show signs similar
to engine
overheating.
To avoid this, let your vehicle operate in a parked position with
the transmission in
“N” (Neutral) for a few minutes before you turn off the
engine. If you do get the overheat warning, see “Engine Overheating” in
the Index.
If you have an automatic transmission, you should use
“D” (or, as you need
to, a lower gear) when towing a trailer. Operating your vehicle in
“D” when
towing a trailer will minimize heat buildup and extend the life
of your
transmission.
If you have a manual transmission 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.
2.
3.
4.
5.
6.
Apply your regular brakes, but don’t shift into “P’ (Park) yet, or in gear
for a manual transmission.
Have someone place chocks under the trailer wheels.
When the wheel chocks are in place, release the regular brakes until the
chocks absorb
the load.
Re-apply the regular brakes. Then apply your parking brake, and then
shift to
“P7, (Park), or “R” (Reverse) for a manual transmission.
If
you have a four-wheel-drive vehicle, be sure the transfer case is in a
drive gear-not in
“N7 (Neutral).
Release
the regular brakes.
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A 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
suddenly. You or others could be injured.
To be sure your vehicle
won’t move, even 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 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
fluid (don’t overfill), engine oil,
axle lubricant, belts, 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.
Trailer Light Wiring
See “Trailer Wiring Harness” in the Index.
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Brakes
Brake Master Cylinder
Your brake master
cylinder is here. It is
filled with
DOT-3
brake fluid.
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.
Refer
to the Maintenance Schedule to determine when to check your brake
fluid. See “Periodic Maintenance Inspections”
in the Index.
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Brake Wear
Your vehicle has front disc brakes and rear drum brakes. If you have a
C 3500 HD model, it 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 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.
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.
If
you have rear drum brakes, they 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.
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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.
Other Maintenance Hems
Front Suspension and Steering Linkage
Your maintenance schedule will tell you how often to lubricate the fittings.
See “Recommended Fluids and Lubricants”
in the Index for the proper
lubricant to use.
Front Wheel Bearings
Your vehicle has front wheel bearings that must be cleaned and repacked.
Your maintenance schedule
will tell you how often this must be done.
Front Shock Absorbers
The front shock absorbers of your vehicle do many things. They help the
vehicle ride smoothly and also control
the travel of the suspension system.
When the shock absorbers are serviced, any replacement shock absorbers
must be
the same as the original equipment shock absorbers in both
extended length and strength.
NOTICE:
If you use shock absorbers that are not the same as the original
shock absorbers, the shock absorbers
or suspension system
could be damaged.
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After you’ve loaded your vehicle and camper, drive to a weigh station and
weigh
on the front and rear wheels separately. This will tell you the loads on
your axles. The loads
on the front and rear axles shouldn’t be more than
either of the GAWRs. The total
of the axle loads should not be more than
the GVWR.
Open your driver’s door and look at
the CertificatiodTire label to find out
your CWAR and GVWR.
If
you’ve gone over your weight ratings, move or take out some things until
all the weights fall below the ratings. Of course, you should always tie down
any loose items when you load your vehicle or camper.
When you install and load your slide-in camper, check the manufacturer’s
instructions.
If
you want more information on curb weights, cargo weights, cargo weight
rating and the correct center of gravity zone for your vehicle, your dealer
can help
you. Just ask for a copy of “Consumer Information, Truck-Camper
Loading.”
Trailer Recommendations
You must subtract your hitch loads from the CWR for your vehicle. Weigh
your vehicle with
the trailer hitch attached, so that you won’t go over the
GVWR or the GAWR.
You’ll get the best performance if you spread out the weight of your load
the right way, and if‘ you choose the correct hitch and trailer brakes.
For more information, see “Trailer Towing’’
in the Index.
Pickup Conversion To Chassis Cab
General Motors is aware that some vehicle owners may consider having the
pickup box removed and
a commercial or recreational body installed.
Before
you do so, first contact the GM Zone Office for your area for
information on such conversions. (See the “Warranty and Owner
Assistance” booklet for Zone Office.) Owners should be aware that, as
manufactured, there are differences between a chassis cab and a pickup with
the box removed which may affect vehicle safety. The components
necessary to adapt
the pickup to permit its safe use with a specialized body
should be installed by a body builder
in accordance with the information
available from
the Zone Office.
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24. DRIVE AXLE SERVICE? - Check readfront axle fluid level and
add
as needed. Check constant velocity joints and axle seals for
leaking.
0
0
0
0
Locking differential - Drain fluid at first oil change and refill.
Check fluid level and add
as needed at subsequent oil changes. In
dusty areas, or trailer towing applications drain fluid at every
15,000 miles (24 135 kilometers) and refill.
Standard differential - Check fluid level and add as needed at
every
oil change. In dusty areas, or trailer towing applications,
drain fluid every
15,000 miles (24 I35 kilometers) and refill.
More frequent lubrication may be required on heavy-duty or
off-road use.
3500 HD Models - 3500 HD Models with applications requiring
extreme overload/trdiler tow conditions
and high speed conditions
(above 45 mph (72
kdh)) for extended periods of time must
change drive axle fluid every
3,000 miles (4828 kilometers) or 3
months, whichever comes first, OR must use 75W-140 synthetic
fluid meeting
GM specifications. See “Recommended Fluids and
Lubricants” at the end of this section for the proper fluid to use.
25.
BRAKE SYSTEM INSPECTION-f - When the engine oil is
changed, inspect the lines and hoses for proper hookup, binding, leaks,
cracks, chafing, etc. Check the parking brake adjust, and the fluid level
in the master cylinder. A low fluid level can indicate worn disc brake
pads which may need
to be serviced.
When the wheels are removed for rotation, inspect disc brake pads for
wear and rotors for surfxe condition. Also inspect drum brake linings
for wear and cracks. Inspect other brake parts, including drums, wheel
cylinders, parking brake, etc., at the same time. Remove any
rust or dirt
from the wheel and mounting surfaces before mounting the wheel.
Inspect brakes more often if driving habits or conditions result in
frequent braking.
?A fluid loss in these systems may indicate a problem. Have them
inspected and repaired at once.
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