brake CHEVROLET TAHOE 1999 1.G Service Manual

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4-52 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 the vehicle's
hydraulic brake system only if:

The trailer parts can withstand 3,000 psi
(20 650 kPa) of pressure.

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
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 ªEngine Exhaustº 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 the
recirculation button or MAX because it
only recirculates the air inside your vehicle.
(See ªComfort Controlsº in the Index.)

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4-53
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.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.

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4-54 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.
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.
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.
You should 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).
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 ªEngine Overheatingº in
the Index.

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4-55 Parking on Hills
CAUTION:
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
PARK (P) yet.
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 then shift to PARK (P).5. If you have a four
-wheel-drive vehicle, be sure
the transfer case is in a drive gear
-- not in
NEUTRAL (N).
6. Release the regular brakes.
CAUTION:
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).

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4-56 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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4-58
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.

Brown: Rear Lamps

Yellow: Left Stoplamp and Turn Signal

Dark Green: Right Stoplamp and Turn Signal

White (Heavy Gauge): Ground

Light Green: Back
-up Lamps

White (Light Gauge): Center High
-Mounted
Stop Lamp

Blue: Auxiliary/Electric Trailer Brake Circuit

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.
Power Winches
If you wish to use a power winch on your vehicle, only
use it when your vehicle is stationary or anchored.
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.

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5-4
2. Get the vehicles close enough so the jumper cables
can reach, but be sure the vehicles aren't touching
each other. If they are, it could cause a ground
connection you don't want. You wouldn't be able to
start your vehicle, and the bad grounding could
damage the electrical systems.
To avoid the possibility of the vehicles rolling, set
the parking brake firmly on both vehicles involved in
the jump start procedure. Put an automatic
transmission in PARK (P) or a manual transmission
in NEUTRAL (N) before setting the parking brake.
If you have a four
-wheel-drive vehicle, be sure the
transfer case is not in NEUTRAL (N).
3. Turn off the ignition on both vehicles. Unplug
unnecessary accessories plugged into the cigarette
lighter or accessory power outlets. Turn off all lamps
that aren't needed as well as radios. This will avoid
sparks and help save both batteries. And it could
save your radio!
NOTICE:
If you leave your radio on, it could be badly
damaged. The repairs wouldn't be covered by
your warranty.
4. Open the hoods and locate the batteries. Find
the positive (+) and negative (
-) terminals on
each battery.
CAUTION:
If your vehicle has air conditioning, the auxiliary
electric fan under the hood can start up even
when the engine is not running and can injure
you. Keep hands, clothing and tools away from
any underhood electric fan.

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5-19
Engine Fan Noise
Your vehicle has a clutched engine cooling fan. When
the clutch is engaged, the fan spins faster to provide
more air to cool the engine. In most everyday driving
conditions, the fan is spinning slower and the clutch is
not fully engaged. This improves fuel economy and
reduces fan noise. Under heavy vehicle loading, trailer
towing and/or high outside temperatures, the fan speed
increases as the clutch more fully engages. So you may
hear an increase in fan noise. This is normal and should
not be mistaken as the transmission slipping or making
extra shifts. It is the cooling system functioning
properly. The fan will slow down when additional
cooling is not required and the clutch disengages.
You may also hear this fan noise when you start the
engine. It will go away as the fan clutch disengages.
If a Tire Goes Flat
It's unusual for a tire to ªblow outº while you're driving,
especially if you maintain your tires properly. If air goes
out of a tire, it's much more likely to leak out slowly.
But if you should ever have a ªblowout,º here are a few
tips about what to expect and what to do:
If a front tire fails, the flat tire will create a drag that
pulls the vehicle toward that side. Take your foot off the
accelerator pedal and grip the steering wheel firmly.
Steer to maintain lane position, and then gently brake to
a stop well out of the traffic lane.
A rear blowout, particularly on a curve, acts much like a
skid and may require the same correction you'd use in a
skid. In any rear blowout, remove your foot from the
accelerator pedal. Get the vehicle under control by
steering the way you want the vehicle to go. It may be
very bumpy and noisy, but you can still steer. Gently
brake to a stop
-- well off the road if possible.
If a tire goes flat, the next part shows how to use your
jacking equipment to change a flat tire safely.

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5-20
Changing a Flat Tire
If a tire goes flat, avoid further tire and wheel damage
by driving slowly to a level place. Turn on your hazard
warning flashers.
CAUTION:
Changing a tire can cause an injury. The vehicle
can slip off the jack and roll over you or other
people. You and they could be badly injured.
Find a level place to change your tire. To help
prevent the vehicle from moving:
1. Set the parking brake firmly.
2. Put the shift lever in PARK (P).
3. If you have a four
-wheel-drive vehicle,
be sure the transfer case is in a drive
gear
-- not in NEUTRAL (N).
4. Turn off the engine.
To be even more certain the vehicle won't move,
you can put blocks at the front and rear of the
tire farthest away from the one being changed.
That would be the tire on the other side of the
vehicle, at the opposite end.
The following steps will tell you how to use the jack and
change a tire.
Removing the Spare Tire and Tools
The equipment you'll need is located in the rear cargo
area. You'll also find your spare tire there.
On two
-door utility and Suburban models, the spare tire
is located at the rear of the vehicle. To remove the spare
tire, first open the tire cover, if you have one. Turn the
wing nut counterclockwise and take it, and the adapter,
off the bolt. Take the tire out of the vehicle and remove
the tire cover.

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5-31
NOTICE:
Improperly tightened wheel nuts can lead to
brake pulsation and rotor damage. To avoid
expensive brake repairs, evenly tighten the wheel
nuts in the proper sequence and to the proper
torque specification.
11. Put the wheel trim back on. For vehicles with
plastic wheel nut caps, tighten the caps until they
are finger tight, then tighten them an additional
one
-half of a turn with the ratchet and
wheel wrench.
Storing a Flat or Spare Tire and Tools
CAUTION:
Storing a jack, a tire or other equipment in the
passenger compartment of the vehicle could
cause injury. In a sudden stop or collision, loose
equipment could strike someone. Store all these
in the proper place.
Store the flat tire where the spare tire is stored.
Put the tools into the storage box and close it tightly. Fit
the storage box on the bracket with the bolt through the
box. Put the jack onto the box. Be sure the jack is stored
as shown in the following illustrations. The jack handle
attachment point is circled in the following illustrations
to show the direction the jack should face when it is
stored properly. Secure the emergency gloves, if your
vehicle has them, to the jack using the provided strap.
Slide the retainer over the bolt onto the jack and put the
wing nut on it. Turn the nut clockwise until it is tight
against the retainer.