1953 JEEP DJ spark plugs replace

H

ELECTRICAL
SYSTEM
the condenser. Replace the condenser. If there is
no jump to full voltage, overhaul or replace the

distributor.

k.
With the points closed, connect the voltmeter

from
a clean, paint-free
post
on the distributor
body to the negative
post
of the battery. The volt­
age drop should be practically zero, a hardly
readable deflection on the voltmeter. If the volt­ meter registers a
voltage
drop, perform the checks

in
steps
1
and m following.

I.
Check
for
voltage
drop in the battery ground
cable.
Clean
the battery
post,
cable terminals, and contact surface on the bellhousing, or on body if

a
noticeable deflection of the voltmeter occurs,
m.
Check
for any
voltage
drop
between
the dis­

tributor
body and a clean, paint-free
spot
on the

cylinder
block. If there is any
voltage
drop, remove
the distributor and clean the mounting surfaces of
distributor
body and cylinder block.

H-5.
SECONDARY
CIRCUIT
If
satisfactory ignition is not obtainable with cor­

rect
point gap and tension; satisfactory condenser;
sufficient primary voltage; and correctly cleaned, gapped, and installed spark plugs; the secondary

circiut
should be investigated.

a.
Test the coil.
Bring
the coil up to operating
temperature using the coil heat feature of a coil tester, if available. Refer to the coil tester manu­

facturer's
instructions for specific hook-ups for
performing the checks given in
steps
b, c, and d following.
b. Connect the positive lead of the tester to the
battery terminal of the coil primary winding.
Con­
nect the tester ground lead to the coil tower. Mea­

sure
the resistance of the secondary winding. If the
resistance is more than
20,000
ohms, a fault in the
secondary winding is indicated.
c.
Check
for a grounded secondary by touching the tester ground lead to the coil cover. If resistance
is not over
100,000
ohms, the secondary is grounded
to the cover.

d.
If the secondary winding is satisfactory, mea­
sure
the primary current draw in accordance with
the instructions of the
test
equipment manu­
facturer.

e.
Check
the secondary circuit for leakage. With the coil primary in the circuit with the breaker unit of the tester, connect a long, high-tension
test
lead
to the coil tower.
Check
the secondary circuit for
leakage by performing the checks given in
steps
f. g, h, and i following.

Note:
In the following
tests,
a slight sparking and
meter deflection
will
usually be
seen
just as contact
is made.
This
is caused by capacitance and
does
not
indicate defective insulation.
f.
Check
distributor cap. Remove the coil lead from the cap and touch the
test
lead to the center contact
inside the cap. If the meter reading drops when the contact is touched or if sparking is seen, a leakage
path is present
between
the center contact and one
of the plug towers.
This
leakage path
will
be in the

form
of a
crack
or carbon track in the cap. Discon­ nect the spark plug wires from the cap one at a
time and
test
each plug contact with the high-
voltage
lead and with all other plug wires con­
nected. Any sparking or meter drop indicates that

a
leakage path exists
between
that particular con­
tact and an adjacent one. Testing the adjacent contacts
will
determine which pair is at fault,
g-
Check
distributor rotor. Touch the
test
lead to
the spring contact in the center of the distributor
rotor.
Any leakage in the rotor insulation
between

the contact and the shaft
will
cause a drop in the meter reading and usually sparking
will
be seen.

h.
Check
spark plug wires. Disconnect the spark
plug wires from the plugs and
test
the plug terminal of each. The meter reading should not drop below
the open secondary value (value before making contact). If it
does
or if a large spark occurs when
the
test
lead and the plug wire are separated, there
is a break in the insulation on that wire.

i.
Check
the coil tower insulation. Remove the
high-tension
test
lead from the coil tower and touch
the ground lead of the coil tester to several points

around
the base of the tower. Any sparking or deflection of the meter indicates a leakage path in
the tower insulation.

H-6.
Alternator Charging System

All
Jeep
Universal
Series vehicles have, as standard
equipment a 35-amp., 12-volt, negative ground
alternator and a transistorized
voltage
regulator.
For
repairing the alternator, many of its major components are furnished as complete assemblies

including:
complete brush assembly which requires no soldering or unsoldering of leads; two complete
rectifying
diode
assemblies which eliminate the need for removing and replacing individual diodes;

a
complete isolation
diode
assembly; and a rotor assembly complete with shaft,
pole
pieces, field coil,

and
slip rings.

The
transistorized
voltage
regulator is an electronic
switching device. It
senses
the
voltage
appearing at the auxiliary terminal of the alternator and
supplies the necessary field current for maintaining the system
voltage
at the output
terminal.
The out­
put current is determined by the battery electrical

load;
such as headlights, heater, etc.
The
transistorized
voltage
regulator is a sealed unit,
has no adjustments, and must be replaced as a
complete unit.

H-7.
Starting System

The
operation of the starter motor is controlled by
the ignition switch. The starter is made up of a
frame,
field coil, armature, and brushes.

The
starter solenoid electrically
closes
the circuit

between
the battery and the starter motor. When the ignition key is turned to its extreme right, the
solenoid is energized and
closes
the battery-to- starter-motor circuit.

Note:
All Jeep Universal Series vehicles have the

starter
solenoid switch secured to the starter motor
assembly. The Hurricane F4 and Dauntless V-6

engine
Prestolite starter drive is of the inertia type
(rexr
continued on
page
176) 174

H

ELECTRICAL
SYSTEM

14365

FIG.
H-5—WIRING
DIAGRAM—F4
ENGINE
CURRENT
MODEL
1—
Left
Headlamp

2—
Left
Parking and Signal Lamp
3—
Right
Parking and Signal Lamp

4—
Right
Headlamp
5—
Marker
Lamp
— Amber
6—
Generator
7—
Distributor

8—
Ignition
Coil

9— Starting Motor
10— Battery Ground Cable
11—
12
Volt
Battery

12—
Flasher
(Directional Signal)
13— Instrument Cluster
A—Hi-Beam
Indicator

B—Auxiliary
C—Instrument Lights
D—Oil
Pressure
Indicator
E—Charging Indicator
F—Temperature Indicator
G—Fuel
Gauge
Indicator
H—Instrument Voltage Regulator
14—
Ignition
and
Starter
Switch
15—
Horn
Button 16—
Directional
Signal Switch 17— 4-Way
Flasher
Switch
18—
Flasher
(4-Way)
19—
Windshield
Wiper Motor Switch
20—
Main
Light
Switch

21—
Fuel
Gauge
Tank
Unit

22—
Back-Up
Light
Switch
23—
Marker
Lamp — Red 24—
Right
Tail
and Stop Lamp
25—
Right
Back-Up Lamp
26—
Left
Back-Up Lamp
27—
Right
Tail
and Stop Lamp
28—
Marker
Lamp — Red 29— Stop
Light
Switch
30— Foot Dimmer Switch

31—
Windshield
Wiper Motor Assembly

32—
Voltage Regulator
33— Temperature Sending
Unit

34—
Oil
Pressure
Sending
Unit

35— Spark
Plugs
&
Cables

36—
Horn

37— Junction Block
38—
Marker
Lamp — Amber
through a
two-position
push-pull switch located on
the
left
side
of the control panel.
The
foot-operated
headlight dimmer switch is
mounted on the floorboard to the
left
of the steering
column.

H-9.
PRESTOLITE
DISTRIBUTOR
—
DAUNTLESS
V-6 and

HURRICANE
F4
ENGINE

The
Prestolite distributor on the F4
engine
is
mounted on the right
side
of the
engine
and is op­
erated by a coupling on the oil pump shaft, see Fig.
D-l,
which is driven by a spiral gear on the cam­
shaft. The spark advance is fully automatic, being controlled by built-in centrifugal
weights.
The Pres­

tolite
distributor on the V-6
engine
(Fig. H-8) is mounted at the
left
front of the
engine
on the tim­
ing chain cover. It is driven by a spiral gear on the
camshaft. The spark advance is fully automatic,
being controlled by built-in centrifugal
weights,
and by a vacuum advance system. While
some
parts of the distributor may be checked or replaced
with the unit mounted on the
engine,
it is
best
to periodically remove it for a thorough check. Infor­ mation covering the parts which can be serviced
without removal is
given
below.
The
Prestolite distributor installed on the V-6 en­

gine
is similar in construction to the distributor in­
stalled on the F4
engines
except
for the addition of

a
vacuum advance mechanism.
The
same checking procedures outlined in Par. C- 10a, are used for the Prestolite V-6 distributor with

exception
of specifications.
H-10. Distributor Cap

The
distributor cap should be inspected for cracks,
carbon runners and
evidence
of arcing. If any of

these
conditions
exists, the cap should be replaced.
Clean
any corroded high
tension
terminals.

H-11.
Rotor
Inspect the rotor for cracks or
evidence
of
excessive

burning at the end of the metal strip.
After a distributor rotor has had normal use the
end of the rotor will
become
burned. If burning is found on top of the rotor it indicates the rotor is
too short and
needs
replacing. Usually when this condition is found the distributor cap
segment
will 178

ELECTRICALJ
SYSTEM

d.
Inspect for
excessive
wear
between
centrifugal

weights
and advance cam and pivot pins.
Turn
weight
base plate in a clockwise direction until
weights
are fully extended. Release and allow
springs to return
weights
to
retard
position. Repeat several times. Springs should return
weights
to
stop
without sticking and there should be no
excessive
free
movement
in the
retard
position. Inspect
springs for distortion and fatigue.
e. Inspect cam
lobes
for scoring or
excessive
wear.
Check
weight
base plate for binding or
excessive

looseness
on distributor shaft.

f.
Check
breaker plate for
excessive
looseness
on
outside
diameter of upper distributor shaft bushing.
Check
breaker plate ground lead for poor
spot
we
Id

at plate end and for
loose
or frayed terminal con­
nections.
g.
Check
for
excessive
wear
between
distributor
shaft and bushings in housing. Inspect shaft for distortion. Inspect gear for scoring of
teeth
or

excessive
wear.

h.
Inspect rod end of vacuum advance mechanism
for
excessive
wear. Push rod
into
unit as far as
possible, hold finger tightly over nipple, then re­
lease
rod. After about 15 seconds, remove finger
from nipple, and
notice
if air is drawn
into
unit.
If
not, diaphragm is leaking and unit must be
replaced.

H-29.
Distributor Reassembly

Refer
to Fig. H-l5.

a.
Install
distributor
primary
lead and rubber grommet in distributor housing. Mount vacuum
advance unit on housing with two
slotted
attaching
screws; insert ground lead terminal of breaker plate under outer mounting screw.
b.
Install
felt
washer over upper shaft bushing of
distributor housing and apply a few drops of light

oil.
Secure breaker plate to upper bushing with re­ tainer. See Fig. H-17.
12767

FIG.
H-17—INSTALLING
BREAKER
PLATE
ON
DISTRIBUTOR
HOUSING
(DELCO)

1—
Breaker
Plate
2—
Retainer

3—
Retainer
Groove
4—
Lubricant
Reservoir c.
Install
distributor cam and
weight
base plate
on distributor shaft.

d.
Insert distributor shaft
into
distributor housing.
Install
centrifugal advance
weights
and springs on

cam
and
weight
base plate. e. Fasten driven gear to shaft with pin. Be care­
ful
not to damage gear.

f.
Secure condenser and bracket to breaker plate
with
slotted
screw.
g.
Install
breaker point assembly over
boss
on
breaker
plate; secure with two
slotted
screws and
lock washers. Apply one drop of light oil to breaker

arm
pivot. Connect condenser and coil
primary

leads to breaker point assembly.

h.
Apply a small amount of high temperature cam

and
ball
bearing lubricant to a clean cloth; hold cloth against distributor cam while turning
distri­
butor shaft.

Caution:
Do not apply
excessive
grease. Petro­
leum jelly is not suitable as a distributor cam
lubri­
cant.

i.
Make preliminary adjustment of breaker point
gap, as described in Par. C-10.

].
Secure rotor to centrifugal timing advance mech­
anism with two screws, lock washers, and flat
washers.

Note:
The square and round
lugs
on the rotor must
be positioned in the corresponding
holes
in the

weight
base plate.
k. If a reliable distributor tester is available, check
the distributor to make certain that the centrifugal

and
vacuum advance mechanisms are operating
according to specifications.

Note:
Mount distributor in tester with all end play
of the distributor shaft in upward position; this

will
eliminate any possible drag
between
the centri­ fugal advance cam and
weight
base plate.

I.
Install
new
O-ring
seal on distributor housing.

H-30.
Distributor
Installation
and
Timing

a.
Insert distributor shaft
into
timing gear cover
of
engine
so that rotor is pointing to
mark
made on distributor base (Fig. H-14), with vacuum advance
unit pointing in exact, original direction (Fig.

H-18).

b.
Install
distributor clamp and
bolt
with lock
washer, leaving
bolt
just
loose
enough
to permit
movement
of the distributor with heavy hand
pressure.

C.
Connect
primary
wire to distributor side of coil.
Install
distributor cap on distributor housing. Press

screwdriver
into
upper
slotted
ends
of two cap
retainers.
Turn
retainers clockwise to secure cap to distributor.

d.
If
spark
cables were disconnected from
distri­

butor cap, connect them. Wires must be pushed

all
the way down
into
the distributor cap terminals
and
onto
the
spark
plugs. Nipples must be pushed
firmly
over the terminals;
boots
must be pushed

firmly
over the
spark
plugs. 186

H

ELECTRICAL
SYSTEM
colder plug may be desirable. However, under- or
over-heating is usually caused by factors other than the type of
spark
plugs and the cause should be determined before changing plugs. The design of the
engine
calls for plugs equivalent to Champion

J-8
for F4
engines
and
A.C.
44S or
UJ12Y
Champ­

ion for the V6 engines, (as installed in production)
though any factor that consistently affects
engine
operating temperature may cause this requirement
to change. Overheating may be caused by in­ sufficient tightening of the plug in the head, which interferes with the flow of heat away from the firing

tip.
If this is the case, the plug gasket
will
show very
little flattening. Over-tightening, in
turn,
will
pro­ duce too easy a heat flow path and result in cold
plug operation.
This
will
be evident by excessive
flattening
and
deformation of the gasket.
Prevailing
temperatures, condition of the cooling system, and

air-fuel
mixture can affect the
engine
operating temperature and should be taken into consideration.
H-34.
GENERATOR
— F4
ENGINE

The
generator is an air-cooled, two-brush unit

which
cannot be adjusted to increase or decrease output. For replacement,
voltage
regulator and generator must be matched for
voltage
and capa­

city,
polarity, and common source of manufacture.
Otherwise,
either a
loss
of ampere capacity or a

burned
out generator
will
result. Generators for

these
vehicles are 12-volt. Par. H-l explains the 12-volt system. Refer to the specifications at the
end of this section for information on correct generator rating for a specific model series.
The
circuit
breaker,
voltage
regulator, and current-

limiting
regulator are built into one combination

unit.
Because the regulator and battery are part
of the generator
circuit,
the output of the generator
depends upon the
state
of charge and temperature
of the battery.
With
a discharged battery, the
output
will
be high, decreasing proportionally as the battery
becomes
charged. For service informa­
tion covering current regulator see Par. H-41.

H-36.
Generator
Maintenance

A
periodic inspection should be made of the charg­
ing
circuit,
Fig. H-l9. The interval
between
these
checks
will
vary
depending upon type of service.
Dust,
dirt
and high speed operation are factors 10541

FIG.
H-19—CHARGING
CIRCUIT

1—
Battery
4-—Starter Switch

2—
Voltage
Regulator 5-—Charge Indicator

3—
Generator
which
contribute to increased wear of bearings

and
brushes.

Under
normal conditions a check should be made
each 6000 miles
[9.600
km.].

A
visual inspection should be made of all wiring,
to be sure there are no broken or damaged wires.

Check
all connections to be sure they are tight and

clean.

Should
the commutator be rough or worn the
armature
should be removed and the commutator

turned
and undercut. See Par. H-37.
The
brushes should slide freely in their holders.

Should
they be oil soaked or if they are worn to

less
than one-half their original length they should
be replaced. When new brushes are installed they should be sanded to provide
full
contact with the
commutator. Generators should not be checked for
output until the brushes are seated.

Brush
spring tension is important. High tension causes
rapid
brush and commutator wear while
low tension causes arcing and reduced output.
Test
the tension with a spring scale.
Check
the
specifications section at end of this section for

correct
spring tension for generator in question.
H-36.
Generator Disassembly
•
Refer to Fig. H-20:
Before beginning disassembly of the generator to

correct
electrical system malfunctions proceed with
inspection and
test
procedures as detailed in Par.

H-46
thru
H-62. If it is definitely determined that trouble exists within the generator, which ne­cessitates dismantling, proceed as follows. Remove the two frame screws in the commutator
end plate and remove the end plate assembly. Next
pull
the armature and drive head complete

from
the generator housing. Remove the generator pulley from the armature by removing the nut

and
washer. Do not
lose
the Woodruff key when
the pulley is removed. After this, remove the drive
end head assembly which includes the oil seal and
bearing.
To remove the bearing, remove the three
screws and lockwashers in the grease retainer and remove the retainer and felt washer, after which,
remove the bearing, oil guard and felt washer.
H-37.
Armature

If
the commutator is rough or worn,
turn
it down

in
a lathe. After turning, the mica insulation be­ tween the
segments
should be undercut to a depth of 34* [0,8 mm.].
To
test
the armature for a ground, connect one

prod
of a
test
lamp to the core or shaft (not on

bearing
surface) and touch each commutator
seg­
ment with the other prod. If the lamp lights, the

armature
segment
is grounded and the armature must be replaced.

To
test
for short in armature coils, a growler,

Fig.
H-21, is necessary. Place the armature on the growler and lay a thin steel strip on the armature

core.
The armature is then rotated slowly by hand

and
if a coil is shorted, the steel strip
will
vibrate.

Should
a coil be shorted the armature must be
replaced.

If
precision
test
equipment is available, the cus­

tomary
accurate
tests
can be made in accordance 188