Fuel System Check; Carburetor Choke Check; Carburetor/Throttle Body Mounting Nut Torque Check; Throttle Linkage Inspection - Jeep cherokee 1989 Owner's Manual

20.14 Peel the wheel cylinder boot back carefully and
-
check for leaking fluid any leakage indicates the cylinder
must be replaced or rebuilt
glazed (shiny surface) or contaminated with brake fluid.
1 3 Make sure that all the brake assembly springs are connected and
in good condition.
1 4 Check the brake components for any signs of fluid leakage. With
your finger or a small screwdriver, carefully pry back the rubber cups
on the wheel cylinders located at the top of the brake shoes (see il-
lustration). Any leakage is an indication that the wheel cylinders should
be overhauled immediately (Chapter 9). Also check brake hoses and
connections for signs of leakage.
1 5 Wipe the inside of the drum with a clean rag and brake cleaner
or denatured alcohol. Again, be careful not to breath the dangerous
asbestos dust.
16 Check the inside of the drum for cracks, score marks, deep
scratches and hard spots, which will appear as small discolorations.
If these imperfections cannot be removed with fine emery cloth, the
drum must be taken to a machine shop equipped to turn the drums.
17 If after the inspection process all parts are in good working condi-
tion, reinstall the brake drum (see Chapter 9).
18 Install the wheels and lower the vehicle.
Parking brake
19 The parking brake operates from a foot pedal or hand lever and
locks the rear brake system. The easiest, and perhaps most obvious
method of periodically checking the operation of the parking brake as-
sembly is to park the vehicle on a steep hill with the parking brake set
and the transmission in Neutral. If the parking brake cannot prevent
the vehicle from rolling, it's in need of adjustment (see Chapter 9).

21 Fuel system check

Warning: Take certain precautions when inspecting or servicing the
fuel system components. Work in a well ventilated area and don't a 1 1 0 w
open flames (cigarettes, appliance pilot lights, etc.) in the work area.
Mop up spills immediately and don't store fuel soaked rags where they
could ignite. On fuel injection equipped models the fuel system is under
pressure. No components should be disconnected until the pressure
has been relieved (see Chapter 4).
1 On all models, the fuel tank is located under the rear of the vehicle,
covered by a shield.
2
The fuel system is most easily checked with the vehicle raised on
a hoist so the components underneath the vehicle are readily visible
and accessible.
3
If the smell of gasoline is noticed while driving or after the vehicle
has been in the sun, the system should be thoroughly inspected im-
mediately.
4 Remove the gas tank cap and check it for damage, corrosion and
an unbroken sealing imprint on the gasket. Replace the cap with a new
one if necessary.
5 With the vehicle raised, check the gas tank and filler neck for punc-
tures, cracks and other damage. The connection between the filler neck
The Motor Manual Guy
Chapter 1 Tune-up and routine maintenance
and the tank is especially critical. Sometimes a rubber filler neck will
leak due to loose clamps or deteriorated rubber; these are problems
a home mechanic can usually rectify. Warning: Do not, under any
circumstances, try to repair a fuel tank yourself (except rubber com-
ponents). A welding torch or any open flame can easily cause the fuel
vapors to explode if the proper precautions are n o t taken!
6 Carefully check all rubber hoses and metal lines attached t o the
fuel tank. Look for loose connections, deteriorated hoses, crimped lines
and other damage. Follow the lines to the front of the vehicle, care-
fully inspecting them all the way. Repair or replace damaged sections
as necessary.
7 If a fuel odor is still evident after the inspection, refer to Section 41.

22 Carburetor choke check

1 The choke operates oniy when the engine is cold, so this check
should be performed before the engine has been started for the da
2
Remove the top plate of the air cleaner assembly. It's usually he
in place by a wing nut at the center. If any vacuum hoses must be
disconnected, make sure you tag the hoses for reinstallation in their
original positions. Place the top plate and wing nut aside, out of the
way of moving engine components.
3 Look at the center of the air cleaner housing. You will notice a flat
plate at the carburetor opening. This is the choke plate.
4 Press the accelerator pedal to the floor. The plate should close com-
pletely. Start the engine while you watch the choke plate. Don't posi-
tion your face near the carburetor, as the engine could backfire, caus-
ing serious burns. When the engine starts, the choke plate should open
slightly.
5 Allow the engine to continue running at an idle speed. As the engine
warms up to operating temperature, the plate should slowly open,
allowing more air to enter through the top of the carburetor.
6 After a few minutes, the choke plate should be fully open t o the
vertical position. Tap the accelator to make sure the fast idle cam dis-
engages.
7 You'll notice that the engine speed corresponds to the plate open-
ing. With the plate fully closed, the engine should run at a fast idle
speed. As the plate opens and the throttle is moved t o disengage the
fast idle cam, the engine speed will decrease.
8 Refer t o Chapter 4 for specific information on adjusting and ser-
vicing the choke components.
23 Carburetorlthrottle body mounting nut torque check
1 The carburetor or Throttle Body Injection (TBI) unit is attached to
the top of the intake manifold by several bolts or nuts. These fasteners
can sometimes work loose from vibration and temperature changes
during normal engine operation and cause a vacuum leak.
2 If you suspect that a vacuum leak exists at the bottom of the car-
buretor or throttle body, obtain a length of hose. Start the engine and
place one end of the hose next to your ear as you probe around the
base with the other end. You will hear a hissing sound ~f a leak exists
(be careful of hot or moving engine components when performing this
check).
3 Remove the air cleaner assembly, tagging each hose to be discon-
nected with a piece of numbered tape to make reassembly easier.
4 Locate the mounting nuts or bolts at the base of the carburetor
or throttle body. Decide what special tools or adapters will be neces-
sary, if any, to tighten the fasteners.
5 Tighten the nuts to the specified torque. Don't overtighten them,
as the threads could strlp.
6 If, after the nuts or bolts are properly tightened, a vacuum leak
still exists, the carburetor or throttle body must be removed and a new
gasket installed. See Chapter 4 for more information.
7
After tightening the fasteners, reinstall the air cleaner and return
all hoses to their original positions.

24 Throttle linkage inspection

1 Inspect the throttle linkage for damage and missing parts and for
binding and interference when the accelerator pedal is depressed.
Lubricate the various linkage pivot points with engine oil.
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