1997 GMC JIMMY brakes

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 in.jured.
Pull a trailer only
if you have followed all the
steps in this section.
Ask your GR/I dealer for
advice and information about towing a trailer with vour vehicle.
I 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.
4-45

Will you have to make any holes in the body of your
vehicle when you install
ti trailer hitch'?
If you do. then be sure to seal the holes later when
you remove the hitch.
If you don't seal them, deadly
carbon monoxide
(CO) f~-om your exhaust can get
into your vehicle (see "Carbon Monoxide"
in the
Index).
Dirt and water can, too.
Safety Chains
you should always attach chains between yo11r 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
manufilcturer
or by the trailer manufacturer. Follow the
manufacturer's recommendation for attaching safety
chains and
clo not attach them to the blmper. Always
leavejust 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
n1aintain them properly.
Your trailer*s
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.
0 The traileras brake system will use less th;m
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, then make the brake
tluid tap at the port on the master cylinder that sends
fluid to the
ear brakes. But don't use copper tubing for
this. If you do, it will bend and finally break off. Use
steel brake tubing.
4-49

1.
L. 7
3.
4.
5.
6.
Apply your regultu- brakes, but don‘t shift into
PARK (P) yet. or into gear for a nxmual
transmission. Then
t111-n your wheels into the curb if
facing downhill or into traffic if facing uphill.
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 reglrlar brakes. Then apply your parking
brake,
and then shift into PARK (P). or
REVERSE (R) for a manual transmission.
If yo^^ have ;t I’our-~yheel-dl-ive \:ellick with a
manual transfer case shift lever, be SLIR the transfer
case
is in a drive gear -- not in NEUTRAL (N).
Release the regular brakes. 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
01- others could be
injured.
‘li) be sure your vehicle won’t n~ove, even
when you’re
on fairly level ground, use the steps
that follow.
If you have four-wheel drive with
a nlanual
transfer case shift lever and your transfer case
is
in NEUTRAL (N), your vehicle will he 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).
4-53

When You Are Ready to Leave After
Parking on
a Hill
I, Apply your reg~~lar brakes and lwld 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 nlore 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. ~~xle lubricant, belt, cooling system
and
brakc adjustment. Each of these is covered in this
manurd.
and the Index will help you find then] 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.
4-54

Section 6 Service and Appearance Care
6-3 6-4
6-5
6-6
6-9
6-13
6- 14
6- 1 8
6- 19
6-20
6-2
1
6-23
6-26
6-26 6-26
6-27
6-28
6-32
6-33
6-3
8
6-40
6-49
6-49
6-5 2
6-54
6-57
6-58
6-5 8
6-58
6-62
6-63
6-64 Brakes
Battery
Bulb
Replacement
Windshield Wiper Blade
Repl~tcenwnt
Tires Appemlnce Care
Cleaning
the Inside of Your Vehicle
Care of Safety Belts
Cleaning the Outside
of Your Vehicle
Appearance Care Materiuls
Chart
Vehicle Identification Number (VIN)
Service Parts Identification Label
Electrical System
Replacement Bulbs
Ci,plcities
and Specifications
Air Conditioning Refrigerants

NOTICE:
When using concentrated washer fluid,
follow the manufacturer’s instructions for
adding water.
Don’t mix water with ready-to-use washer
fluid. Water can cause the solution to freeze
and damage your washer fluid tank and
other parts of the washer system.
Also,
water doesn’t clean as well as washer fluid.
three-quarters full when
it’s very cold. This
allows for expansion if freezing occurs,
which could damage the tank if it is
completely full.
Don’t use radiator antifreeze in your
windshield washer. It can damage your
washer system and paint.
Fill your washer fluid tank only
Brakes
Brake Fluid
Y~LII. brake master cylinder reservoir is here. It is filled
with DOT-3 brake fluid.
6-28

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. Refer
to the Maintenance Schedule to determine when to
check your brake fluid. See “Periodic Maintenance
Inspections” in the Index.
Checking Brake Fluid
If you have too much brake fluid, it can spill on the
engine. The fluid
wiu 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.
I
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 MIN. If they aren’t,
have your brake system checked to see
if there is a leak.
After work is done on the brake hydraulic system, make
sure the levels are above
MIN and below the top of
each window.
6-29

What to Add
When you
do need brake fluid, use only DOT-3 brake
fluid
-- such as Delco Supreme 1 l@ (GM Part
No. 12377967). Use new brake fluid from a sealed
container only.
Always clean the brake fluid reservoir
cap and the area
around the
cap before removing it. This will help keep
dirt from entering the reservoir.
I
With the wrong kind of fluid in your brake
system, your brakes may not work well, or they
may not even work
at all. This could cause a
crash. Always use the proper brake fluid.
NOTICE:
Using the wrong fluid can badly damage
brake system parts. For example, just
a few
drops
of mineral-based oil, such as engine
oil, in your brake system can damage brake
system parts
so badly that they’ll have to be
replaced. Don’t let someone put
in the
wrong kind of fluid.
0 If you spill brake fluid on your vehicle’s
painted surfaces, the paint finish
can be
damaged. Be careful not to spill brake fluid
on your vehicle. If you do, wash it off
immediately. See “Appearance Care” in
the Index.
6-30