1998 GMC SIERRA brake

If your slide-in camper and its load weighs less than the
CWR, the center
of gravity zone for your vehicle may
be larger.
Your dealer can help you make a good vehicle-camper
match. He’ll also help
you determine your CWR.
After you’ve loaded your vehicle and camper, drive to a
weigh station and weigh 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 GAWR
and GVWR.
If you’ve gone over your weight ratings, move or take
out some things until all the weight falls 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 attached,
so that you won’t go over the GVWR or 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.
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Towing a Trailer
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 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 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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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 and do not attach them to the bumper. 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 Ibs. (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 the vehicle’s
hydraulic brake system only if
0 The trailer parts can withstand 3,000 psi
(20 650 kPa) of pressure.
0 The trailer’s brake system will use less than
0.02 cubic inch (0.3 cc) of fluid from your vehicle’s
master cylinder. Otherwise, both braking systems
won’t work well. You could even lose your brakes.
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 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.
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During your trip, check occasionally to be sure that the
load is secure, and that the lamps 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
I 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.
Turn Signals When Towing a Trailer
The 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 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 kdh) to reduce the
possibility
of engine and transmission overheating.
If you have an automatic transmission, you can tow in
AUTOMATIC OVERDRIVE
(@). You may want to
shift the transmission
to THIRD (3) or, if necessary, a
lower gear selection
if the transmission shifts too often
(e.g., under heavy loads and/or hilly conditions).
If
you have a manual transmission and you are towing a
trailer, it’s better not to
use FIFTH (5) gear. Just drive in
FOURTH
(4) gear (or, as you need to, a lower gear).
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) (or the
manual transmission out of gear and the parking brake
applied) for a few minutes before turning the engine
off.
If you do get the overheat warning, see “Engine
Overheating’’ in
the Index.
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.
Apply your regular brakes, but don’t shift into
PARK
(P) yet for an automatic transmission, or into
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.
Reapply the regular brakes. Then apply your parking brake and
shift into PARK (P) for an automatic
transmission, or REVERSE (R)
for a manual
transmission.
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5. If you have a four-wheel-drive vehicle,
be sure the transfer case is in
a drive gear and not
in
NEUTRAL (N).
6. Release the regular brakes.
-
/r CAUTIOIA:
It can be dangerous to get out of your vehicle if
the shift lever is not fully in
PARK (P) 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
NEUTRAL (N), your vehicle will be free
to
roll, even if your shift lever is in PARK (P). So,
be sure the transfer case is in a drive gear -- not
in
NEUTRAL (N).
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
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.
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Trailer Wiring Harness
A. Light-Duty Wiring Harness
B. Additional Heavy-Duty Wiring
C. Tie Straps
A eight-wire harness is stored under the rear end of your
vehicle. Five wires (A) are located between the rear
bumper and the spare tire, near the center. This wiring
harnewis tie-strapped to the taillamp and stoplamp
harness. Three wires (B) (light gauge white, blue and
orange) are located at
the rear left hand frame rail. This
harness has a
30 amp battery feed wire and no
connector, and should be wired
by a qualified electrical
technician. After choosing an aftermarket mating
connector pair, have the technician attach one connector
to the eight-wire trailer harness and the other connector
to the wiring harness on the trailer. Be sure that the
wiring harness on the trailer is strapped to the trailer’s
frame and leave
it loose enough so that the wiring
doesn’t bend or break, but not
so loose that it drags on
the ground. The technician can use the following color
code chart when connecting the wiring harness to
your trailer.
0 Brown: Rear Lamps
0 Yellow: Left Stoplamp and Turn Signal
0 Dark Green: Right Stoplamp and Turn Signal
0 White (Heavy Gauge): Ground
0 Light Green: Back-up Lamps
0 White (Light Gauge): Center High-Mounted
Stop Lamp
0 Blue: Auxiliary/Electric Trailer Brake Circuit
0 Orange: Fused Auxiliary Circuit
Store the harness
in its original place. Wrap the harness
together and tie
it neatly so it won’t be damaged.
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Power Winches
If you wish to use a power winch on your vehicle, only
use
it when your vehicle is stationary or anchored.
I NOTICE:
Using a power winch with the transmission in
gear may damage the transmission. When
operating
a power winch, always leave the
transmission in NEUTRAL
(N).
Use the regular brakes, set the parking brake, or block
the wheels
to keep your vehicle from rolling.
Power Take-Off (PTO)
(Manual Transmission)
NOTICE:
If you have a PTO that will exceed 35 hp installed
on your vehicle, it could damage the transfer case
or transmission. When having
a PTO installed on
your vehicle, make sure that it will not exceed
35 hp.
Before using
a PTO, refer to the manufacturer’s or
installer’s instructions.
I NOTICE:
Using a PTO while operating in one place before
the vehicle has reached normal operating
temperature can damage the transfer case or
transmission. If you
will be using the PTO while
operating in one place, drive and warm up the
vehicle before using the PTO.
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