1953 JEEP CJ check engine

'Jeep*
UNIVERSAL SERIES SERVICE
MANUAL

H
long as the circuit values allow the voltage to build
up to the operating voltage.
The
electromagnet of the voltage regulator unit has

a
winding of many turns of fine wire and is con­
nected across the charging circuit so that the sys­ tem voltage controls the amount of magnetism.
The
contacts of the voltage regulator unit are con­
nected in the generator field circuit so that the field

circuit
is completed through the contacts when they

are
closed and through a resistor when the contacts
are
opened.

When
the voltage rises to a predetermined value
there is sufficient magnetism created by the regu­

lator
winding to
pull
the
armature
down.
This
opens

the contacts and inserts resistance in the field
cir­

cuit
of the generator thus reducing the
field
current.
The
generated voltage immediately drops, which
reduces the
pull
on the
armature
to the point where
the spring closes the contacts. The output again

rises
and the cycle is repeated.

These
cycles occur at high enough frequencies to
hold the generated voltage at a constant value and

will
continue as long as the voltage of the circuit
is high enough to keep the voltage regulator unit

in
operation.
With
the addition of a current load great enough to lower the battery voltage below
the operating voltage of the unit, the contacts
will

remain
closed and the generator
will
maintain a
charging
rate as limited by its speed or the current

limiting
regulator.

Due
to the
effect
of heat on the operating
charac­

teristics of regulator windings it is necessary to
compensate for the changes in coil resistance when
the regulator is operating under varying tempera­

ture
conditions.
This
is accomplished through the
use of a nickel iron magnetic by-pass on the volt­
age regulator unit.
This
shunt by-passes
some
of
the magnetic flux when the unit is cold and allows most of the flux to act on the armature when the

unit
is hot.
Thus
when the coil is hot and not as
efficient, the magnetic shunt reduces the amount of flux needed to vibrate the armature.

The
compensation is usually more than enough to

offset
the changes in regulator coil resistance due
to heat. The excess compensation allows the regu­

lator
to operate at higher voltage under cold
operating conditions than under hot conditions.
This
is necessary as it requires a higher voltage to charge a battery with its internal resistance in­

creased
by low temperatures.

H-45.
Current-Limiting
Regulator

The
function of the current-limiting regulator is to limit the output of the generator to its maxi­

mum
safe output.

The
electromagnet of the current regulator unit
consists of
a
winding of heavy
wire
that is connected
in
series with the generator output. When the gen­

erator
output reaches a predetermined value, the
current
in the winding produces enough magnetism
to overcome the spring tension and
pull
the
arma­
ture
down.
This
opens
the contacts and inserts re­
sistance in the field circuit of the generator.
With
the field current reduced by the resistance, the
generator output falls and there is no longer enough
magnetism to hold the contacts open. As soon as
the spring closes the contacts, the output rises and the cycle is repeated. These cycles occur at high
enough frequencies to limit the output to a mini­
mum
fluctuation.

H-46.
Preliminary Inspection

a.
Wiring—Check
the wiring to see that it is prop­
erly
connected to the generator.

b.
Generator
Performance—Make
sure the genera­
tor operates correctly without the regulator in the
circuit.
Remove the armature and battery leads

from
the regulator and connect an ammeter be­
tween them. Remove the field lead from the regu­

lator
and while operating at idle speed touch the
field
lead
to the regulator base. Increase the speed slowly noting the charging rate.

CAUTION:
Do not increase the output above
the rated output of the generator.

If
the generator output
will
not build up inspect
the wiring harness for shorts and
opens
and remove the generator for an overhaul. To check the genera­
tor circuit when a suitable ammeter is unavailable,

Fig.
H-19, disconnect the armature cable at the

regulator.
Connect one lead of
a
12v
test
lamp to the regulator terminal marked "armature" and with
the engine running, ground the other lead. Should
the
test
light
fail
to
burn
there is a fault either in the generator or regulator. To localize the fault, discon­
nect both the
"Field"
and
"Armature"
cables at the generator. Connect a wire from the
"Field"
ter­
minal
to ground and use a 60 watt, 110 volt
test

lamp
to ground the
"Armature"
terminal. If the
generator is charging satisfactorily the
test
lamp

will
glow
at approximately 1500 rpm. engine speed
and
the fault
will
be definitely localized in the
regulator.

c.
Incorrect Regulator—Make sui he regulator
is the correct type for use with the generator.

d.
Battery—Check
the specific gravity and termi­

nal
voltage of the battery. If the \ ttery is not up
to specifications substitute temporarily
for
test
pur­
poses
a fully charged battery of the same type and
capacity.

e. High Resistance Connections—Inspect the
wir­
ing between the generator, regulator and battery for broken wires and high resistance connections.

Pay
special attention to the ground connections at
all
three units. Connect a reliable ammeter with 1-ampere graduations in series with the regulator

B-terminal
and the lead removed from this
terminal.
Run
the generator at a medium speed and
turn
on the lights or accessories until the ammeter shows a 10-ampere charging rate. At this charging rate
measure the voltage drop between the following
points using an accurate voltmeter graduated in
,1-volt divisions. The voltmeter should not show

a
reading above the maximum noted.
Generator
"A" terminal to regulator
"A"
terminal
—.1-volt maximum.

Generator
"F"
terminal to regulator
"F"
terminal
—.05-volt maximum.

Battery
terminal to regulator "B" terminal— .1-volt maximum.

Regulator
ground screw to generator frame— .03-volt maximum. 191

H

ELECTRICAL
SYSTEM
Regulator
ground screw to battery ground post
—.03-volt maximum.

Generator
frame to battery ground post—.03-volt
maximum.

H-47.
Test Procedure

a.
Circuit
Breaker—Connect
an ammeter in series between the regulator B-terminal and the lead
wire
removed from that terminal. Connect a
voltmeter between the regulator
A-terminal
and the regulator mounting base. Disconnect the field lead

from
the regulator
F-terminal
and insert a variable resistance (3 amp., 50 ohm capacity) between the

lead
and the regulator terminal. Run the generator
at about 1000 generator rpm. Insert all the re­
sistance in the field
circuit,
then slowly reduce the
resistance noting the voltage reading just before the change caused by the closing of the circuit

breaker.
Increase the charging rate to the figure
specified for the regulator being tested then reduce
the charging rate by inserting resistance in the
field
circuit.
Note
the voltmeter and ammeter

reading
just before the circuit breaker
opens
and
the ammeter reading drops to zero. The closing voltage and the opening voltage or current should
be within the limits specified. An accurate method
for noting the exact instant of the opening or closing
of the circuit breaker is to connect a headphone (2000 ohms or higher) to the battery and armature

terminals
of the regulator. When the contacts
open or close a
click
will
be
heard
in the headphones.
To
adjust the closing voltage change the armature

spring
tension by bending the hanger at the lower end of the spring. Increase the spring tension to

raise
the closing voltage or decrease the tension
to lower the closing voltage. To adjust the opening voltage raise or lower the stationary contact
keeping the contacts perfectly aligned. Increasing
the contact gap lowers the opening
'
voltage.
Change
the contact gap by expanding or contract­
ing the stationary contact bracket, keeping the
contacts aligned. Do not adjust the gap between
the contacts to less than the specified minimum.

b.
Voltage Regulator—Connect the ammeter as in

step
a. Connect the voltmeter between the regulator
B-terminal
and the regulator base. Remove the

variable
resistance from the field
circuit.
Run the
generator at
half
output for 15 minutes to bring
the regulator to normal operating temperature.

Keep
the cover on the regulator during the
warm-

up period and also when taking readings.
Stop the engine then bring it up to approximately 2500 generator rpm. Adjust the amperage to
half

maximum
output by turning on lights or accessor­
ies and then
note
the voltmeter reading.
This
read­

ing should be within the limits specified for the voltage regulator operation. To adjust the oper­
ating voltage change the
armature
spring tension by
bending the hanger at the lower end of the
arma­

ture
spring. After each adjustment
stop
the engine then restart it.
Bring
it up to speed and adjust the

current
before taking a reading. In order to obtain

an
accurate indication of the operation of the volt­
age regulator unit connect a headphone (2000 ohm

or
higher) between the
F-terminal
and ground to

pick
up the sound of the opening and closing of the
contacts. The clicks should be regular and clear without irregularities or missing. If the
tone
is not

clear
and regular remove the regulator cover and
inspect the contacts. The contacts should be flat
and
not burned excessively and should be aligned
to make
full
face contact. If the contacts need
cleaning refer to paragraph d for the method.

c.
Current
Regulator—Connect the regulator and the
test
equipment as in
step
b. Running the generator at approximately 3000 generator rpm.,

turn
on lights and accessories so that the generator must charge at maximum rate. The ammeter should give a reading within the limits specified.

To
adjust opening amperage, change the armature

spring
tension by bending the hanger at the lower
end of the armature spring. After each adjustment,

stop
the engine, then restart it.
Bring
the engine up to speed and take an ammeter reading. Keep
the cover on the regulator when taking
these

readings.

Connect
a headphone (2000 ohms or higher) be­
tween the regulator
F-terminal
and ground to pick
up the sound of opening and closing of the contacts.

Clear,
regular clicks should be heard over the
headphones; they should not be
irregular
or missing.
If
the
tone
is not clear and regular remove the
regulator cover and inspect the contacts. The
contacts should be flat and not burned excessively

and
should be aligned to make
full
face contact. If
the contacts need cleaning refer to paragraph d.
below for the method.

d.
Contacts—Inspect the contacts on all three
units.
In normal use the contacts
will
become

grayed.
If the contacts are burned or dirty or if they are not smooth, file the contacts with a #6

American,
Swiss cut, equalling file. Move the file

parallel
and lengthwise to the armature.
File
just
enough so that the contacts present a smooth
sur­

face toward each other. It is not necessary to remove every trace of pitting. After filing, dampen

a
piece of linen or lintless bond tape in refined

carbon
tetrachloride and draw the tape between
the contacts. Repeat with a dry piece of tape. Use
clean
tape for each set of contacts.
e. Recheck—Operate the unit at
half
maximum
output for five minutes with the cover on the regu­

lator.
Repeat the testing procedure for all units as described in a, b, c above. Be sure cover is on regu­

lator
when taking readings.

H-48.
Quick
Checks

H-49.
Low Charging Rate with a
Fully
Charged
Battery

A
fully charged battery and a low charging rate
indicates normal regulator operation.
A
further check of the regulator operation can be
made by using the starting motor for 5 to 10
seconds with the ignition switch in the "off" posi­ tion.
Then
start the engine and operate at a genera­
tor speed of 2500 to 3000 rpm. The charging rate should rise to its maximum value then taper off to

a
minimum charge as the battery becomes charged.

H-50.
High Charging Rate with a
Fully
Charged
Battery

This
is usually an indication that the voltage regu­

lator
is not operating correctly. The high voltage 192

'Jeep*
UNIVERSAL
SERIES SERVICE
MANUAL

H
no soldering or unsoldering of leads; two complete

rectifying
diode assemblies
which
eliminate the need
for removing and replacing individual diodes; a
corpplete 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
output current is determined by the battery electri­
cal
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-64. ALTERNATOR
PRECAUTIONS

The
following precautions must be observed to
prevent damage to the alternator and regulator.

a.
Never reverse battery connections. Always

check
the battery polarity with a voltmeter before

any
connections are made to be sure that all con­
nections correspond to the battery ground polarity of the vehicle.

b.
Booster batteries for starting must be properly
connected. Make sure that the negative cable of
the booster battery is connected to the negative

terminal
of the battery in the vehicle. The positive
cable of the booster battery should be connected
to the positive terminal of the battery in the
vehicle.

c.
Disconnect the battery cables before using a fast charger.

d.
Never use a fast charger as a booster for

starting
the vehicle.

e.
Never disconnect the
voltage
regulator while
the
engine
is running.

f.
Do not ground the alternator output terminal.
g.
Do not operate the alternator on an open
circuit
with
the field energized.

h.
Do not attempt to polarize an alternator.

These
precautions are stated here as an aid to

service
personnel. They are also restated at appro­

priate
places in the
text
of this section of the
manual.

H-65. ALTERNATOR
CHARGING
SYSTEM SERVICE
Important:
All alternator
tests
for the 35, 40 and
55 amp alternator are the same, however, there is a
difference
between
the location of the various ter­

minals
and field current specifications. The field

current
of the 35 amp alternator should be 1.7 to 2.3 amps, 40 and 55 amp alternators should be 1.8
to 2.4 amps, with
full
battery
voltage
applied to
the filed coil. Disassembly and assembly procedures

are
the same for all three alternators.
Terminal
locations and wire harness color
codes
for the 35,
40 and 55 amp alternator are shown in Fig. H-38.

H-66.
Service Diagnosis

In
diagnosing a suspected malfunction of the

alternator
charging system, consideration must
be given to the complete electrical power plant of the vehicle; including the alternator, regulator,
ignition switch, charge indicator lamp, battery,

and
all associated wiring. If it is suspected that the

alternator
is not fully charging the battery and

fulfilling
the electrical requirements of the electrical
system, several checks should be made before

checking
the alternator itself:

Note:
Whenever service is required in connection

with
an alternator problem, the first
step
should be to verify that the wiring harness hook-up is correct
as indicated in Fig. H-38.

a.
Test the condition of the battery and
state
of
charge
(Par. H-2).
If the battery is not fully charged
and
in
good
condition, use a replacement battery
for making alternator system
tests.

Caution:
Make certain that the negative battery

post
is connected to ground when making the
battery installation. Serious damage to the alter­

nator
can result if battery polarity is reversed.

b.
Check
fan belt for proper tension (Par.
C-27).

Caution:
To increase belt tension, apply pressure
to alternator front housing only as permanent damage can result if pressure is applied to
rear

housing.

H-67.
Alternator In Vehicle Tests

The
following
tests
are made with the alternator

in
the vehicle with output and regulator connec­
tions maintained to the alternator except as noted

in
Fig. H-27 and H-28. The field plug and
voltage
regulator are disconnected for
these
tests.
The

tests
are given in proper order and detail in the
following paragraphs.

a.
Isolation Diode Test: To determine if the isola­
tion diode is open or shorted, refer to Par. H-69.

b.
Alternator Output Test: To isolate the trouble
to the alternator or regulator, refer to Par. H-70.

c.
Alternator
Field
Circuit
Test: To determine the condition of the field
circuit
(brushes and rotor),

refer
to Par. H-73.

d.
Brush
Insulation
and Continuity
Test:
To deter­
mine the condition of the
brush,
refer to
Par.
H-75.

e.
Rotor In-Vehicle Test: To determine whether
the rotor coil is open or shorted, refer to
Par.
H-73.
f. Any further
tests
must be conducted with the

alternator
removed and disassembled. When this
is done, the condition of the rotor, the rectifying

and
isolation diodes, and the stator can be further
tested.

A
commercial alternator tester Sun
Electric
Model

VAT-20
or equivalent can be used to make all
necessary
tests
on the alternator system. If a com­

mercial
tester is used, follow the recommended
testing procedure outlined by the tester manu­

facturer.
If
a commercial tester is not available, follow the
testing procedure as outlined in this manual.

H-68.
Test Equipment

a.
Volt Ampere Tester such as Sun
Electric
Model

VAT-20
or equivalent with meter ranges as shown

in
the following list can be used. 195

H

ELECTRICAL
SYSTEM DC
ammeter — 0 to 60 ampere

DC
ammeter — 0 to 5 ampere

DC
voltmeter — 0 to 16 volt
Rheostat — 40 ohm capable of
handling
3 amps.

Carbon
Pile — 45 amperes

b.
Diode Rectifier Tester C-3829.

c.
12-volt DC
test
lamp.

d.
Ohmmeter of any commercial type is not ab­solutely necessary but can be helpful.

H-69.
Isolation Diode
Check

With
the ignition key in the off position the correct voltage at the auxiliary terminal is zero volts. If
voltage measured at auxiliary terminal is the same as voltage at output terminal, the isolation diode
is shorted. In most cases, the charge indicator lamp
would be glowing with the ignition off if the isola­ tion diode were shorted. Refer to Fig. H-23.
GREEN

DC
VOLTS
13401

FIG.
H-23—ISOLATION DIODE
TEST-
SHORTED DIODE
With
the engine running the correct voltage at the

auxiliary
terminal is 15.4 volts and at output ter­

minal
is 14.4 volts. If voltage of auxiliary terminal
is 15.4 volts, while at output terminal it is 12 volts

or
battery voltage, the isolation diode is open. In
most cases, this would be indicated by the charge

GREEN

TO
CHARGE
INDICATOR
LAMP1

15.4
VOLTS BLACK
VOLT

REG DC
VOLTS

BATTERY

DC
VOLTS
FIG.
H-24—ISOLATION DIODE
TEST-

OPEN DIODE
indicator
lamp glowing when the engine is running.

Refer
to Fig. H-24.

If
the isolation diode is shorted or open, the heat

sink
and diode should be replaced as an assembly.

At
the time of manufacture, the diode is pressed into the heat sink and the complete assembly is in­
sulated from the alternator housing.

H-70.
Alternator Output Test

This
test
excludes the regulator from the alternator
system, thereby isolating the problem to either the regulator or alternator. Disconnect field and voltage regulator plug and
connect jumper from auxiliary terminal to field

terminal.
Start
engine and run at idle. Refer to

Fig.
H-25.
DC
VOLTS

13403

FIG.
H-25—ALTERNATOR OUTPUT
TEST
If
voltage at auxiliary terminal rises to 15 or 16
volts now, when it did not with voltage regulator
connected, then defect is in regulator and it should
be replaced. If voltage
does
not rise at auxiliary

terminal,
defect is in alternator stator or rectifier diodes, if field circuit checked out properly. For
defects
in stator or diodes, remove alternator from vehicle.

If
rated current output is obtained with at least 13
volts but less than 15 volts at the output terminal,
the alternator is functioning properly.

Caution:
Do not exceed rated current output of
alternator
by increasing load on alternator.

If
rated
current
output cannot be obtained, proceed

with
the
tests
and checks given in the following
paragraphs
and isolate the cause.
Note: The system is designed to produce slightly
more output at low operating temperatures and less
at higher temperatures to accommodate the
varying
demands of electrical power normally consumed at

these
temperatures.

H-71.
Regulator Test

The
regulator should be checked with an alternator
that is functioning properly. If the alternator is questionable, perform the Alternator Output Test
(Par
H-70) which excludes the regulator from the

charging
system and, therefore,
tests
the condition
of the alternator alone. 196

'Jeep'
UNIVERSAL SERIES SERVICE
MANUAL

H
H-72.
Removal
and
Installation
of

Voltage Regulator

The
transistorized
voltage
regulator is a sealed unit.
It
cannot be disassembled or adjusted. If found to
be defective in any way, it must be replaced as
a
unit.

The
transistorized
voltage
regulator is mounted on
the fender dust shield by three mounting screws.

Wiring
connections to the charging circuit are made through a three-prong connector.

To
remove the regulator, disconnect the three
-
prong connector and remove the three mounting

screws.
Installation of the regulator is the reverse
of the removal. (Refer to Fig. H-26.)
FIG.
H-26—VOLTAGE
REGULATOR

H-73.
Alternator Field Circuit Test

Voltage
Test — Refer to Fig. H-27.

a.
With the ignition key on and
engine
not
run­
ning,
the correct
voltage
at the auxiliary terminal is
approximately 1.5 volts. If the
voltage
at auxiliary

terminal
is higher than 2 volts, field circuit is defective — check brushes.
GREEN

13404

FIG.
H-27—FIELD
CIRCUIT TEST—VOLTAGE If
voltage
reads zero volts at auxiliary terminal,
check charge indicator lamp and associated circuit.
If
this
voltage
is not correct, continue with the fol­
lowing
test
described in paragraph b.
Amperage Test — Refer to Fig. H-28. b.
This
test
evaluates complete field circuit, inde­
pendent of
voltage
regulator.
Circuit
is through
brushes, slip rings, rotor to ground. With ignition switch off, current should be 2 to 2.5 amps. If
less

than
this, check brushes and slip rings. It is de­

sirable
to use a field rheostat in series with meter
for protection of the meter. If field is shorted, ex­
cessive current
will
flow through meter and dam­
age may result.
GREEN
FIELD
WIRE

DISCONNECTED

13405

FIG.
H-28—FIELD
CIRCUIT TEST- AMPERAGE
DRAW
H-74.
Brush Removal
and
Inspection

Refer
to Fig. H-29.

The
brushes can be removed and inspected while
the alternator is in the vehicle.

a.
Disconnect the plug to the field terminal. b. Remove the two screws and brush cover.
c. Remove brushes.
d.
Inspect brushes for excessive wear and proper
tension. The brushes can be installed by reversing
the above procedure.

H-75.
Brush Insulation
and
Continuity Test

Refer
to Fig. H-30.

a.
Connect leads of a 12-volt
test
lamp to field
FIG.
H-29—BRUSH
REMOVAL

1—
Screw

2—
Cover

3—
Brush
and
Holder
Assembly
4—
Alternator
197

'Jeep*
UNIVERSAL
SERIES SERVICE
MANUAL

H
13406

FIG.
H-39—STARTING
CIRCUIT

1—
Ground
Cable
2—
Battery

3—
Positive Cable
4—
Alternator
Wire
5—
Alternator

6— Ignition Switch
Wire

H-93.
Maintenance Procedure

A
periodic inspection should be made of the start­ ing circuit. Since the interval
between
these
checks

will
vary according to the type of service, it should, under normal conditions, be made every 500 hours
of operation. Inspect all starting circuit wiring for damage.
Check
for
loose
or corroded terminals and
for dependable operation of the starting motor.

H-94.
Wiring

Refer
to Fig. H-39. Inspect the starting circuit to make sure that all
connections are clean and tight.
Check
for worn or damaged insulation on the wires. Perform a volt­

age-loss
test
to make sure there is no
loss
of start­ ing motor efficiency resulting from high resistance
connections. Voltage
loss
from the battery ter­
minal
to the starting motor terminal should not
exceed .30 volts for each 100 amperes. Voltage
loss
between
the battery ground
post
and the start­ing motor frame should not exceed .10 volts for
each 100 amperes. If the
voltage
loss
is greater
than
these
limits, measure the
voltage
loss
over
each part of the circuit until the resistance causing the
voltage
loss
is located and corrected.

H-95.
Commutator
Sluggish starting motor operation may be caused by a dirty commutator or worn brushes. The com­mutator cannot be cleaned while the. starting motor is mounted on the
engine
and it
will
be necessary
to remove it and proceed as for an overhaul. Should 7— Ignition Switch
8— Solenoid
Wire

9—
Starter

10— Solenoid
11—
Connector
Strap
the commuator be rough or worn, it should be
removed for cleaning and reconditioning.
H-96.
Overhaul Procedure

At
periodic intervals the starting motor circuit
should be thoroughly checked and the motor re­ moved from the
engine
for cleaning and checking.

H-97.
Removal and Disassembly

Refer
to Fig. H-40 and H-41.
To
remove the starting motor from the engine, dis­
connect the leads and cover the battery lead ter­

minal
with a piece of
hose
or tape to prevent short

circuiting.
Remove the flange
bolts
holding the starting motor to the flywheel housing. Remove
the starting motor from the vehicle.

Each
part of the starting motor should be removed, cleaned, and inspected for evidence of wear or
damage. The Bendix
Folo-Thru
Drive should be
cleaned and inspected for evidence of wear or a distorted spring. Bearings should be checked for
proper clearance and fit. All insulation should be
free of oil and in
good
condition. The armature,
field coils, and brushes should be checked for
good
ground and lack of open circuits.

H-98.
Brushes

a.
The brushes should slide freely in their holders
and
make full contact on the commutator. Worn
brushes should be replaced.
b.
Check
brush spring tension with a spring scale.
Hook the scale under the brush spring near the 203

H

ELECTRICAL
SYSTEM

11035

FIG.
H-40—PRESTOLITE STARTING MOTOR—F4 ENGINE 1— End
Plate

2—
Plug

3—
Thrust
Washer
4—
Brush
Plate Assembly 5— Screw
6—
—Lock
Washer
7—
Insulating
Washer
8—
Terminal

9—
Field
Coil
and Pole
Shoe
Set
10—
Frame

11—
Insulating
Washer

12—
Washer

13— Nut 14—
Lock
Washer

15—
Insulating
Bushing

16—
Pole
Shoe
Screw
17— Sleeve Bearing
18—
Drive
End Frame
19—
Intermediate Bearing

20—
Bendix
Drive

21—
Screw

22—
Lock
Washer

23—
Thrust
Washer

24— Key
25—
Armature

26—
Thru
Bolt

27—
Insulator

brush
and
pull
On
a line parallel with the side of
the
brush.
Take
the
reading
just as the spring leaves the
brush.
It is important that the brush spring
tension be kept within the limits specified at the end of this section. If the tension is too low, there

will
be a loss of efficiency from poor brush contact.
Too
great a tension
will
cause excessive brush and
commutator wear. To change the tension, twist the

spring
at the holder with long-nosed pliers,

c.
Worn
brushes should be replaced. Brushes that
are
soldered to the field coil should be unsoldered

and
the
loop
in the field coil lead should be opened.
Insert
the new brush pigtail to its
full
depth in the
loop. The new brush lead should be tightly clinched

in
the terminal and then soldered to make a strong, low-resistance connection.

H-99.
Commutator

Check
the commutator for wear and discoloration.
If
the commutator is rough or worn the armature should be removed and the commutator turned
down in a lathe. A discolored commutator should
be cleaned with carbon tetrachloride. Never use
emery cloth.

H-100.
Armature

Visually
inspect the armature for mechanical
defects
before checking for shorted or grounded
coils. Use a set of
test
probes for testing armature

circuits.
To
test
the armatures for grounds, touch
one point of the
test
probes to a commutator seg­
ment and touch the other point to the core or shaft. Do not touch the points to the bearing surface or
to the brush surface as the arc formed
will
burn

the smooth finish. If the lamp lights, the coil con­ nected to the commutator segment is grounded.
To
test
for shorted armature coils, a growler as
shown-in Fig. H-42 is necessary. The armature is placed against the core and a steel strip is held
on the armature. The growler is then energized 204

UNIVERSAL
SERIES
SERVICE
MANUAL

H

t
^

12956

FIG.
H-41—PRESTOLITE
STARTING
MOTOR—V-6
ENGINE

1—
End
Plate
2—
Oiling
Pad

3—
Thrust
Washer
4—
Brush
Plate Assembly 5—
Screw

6—
Lock
Washer 7—
Insulating
Washer
8—
Terminal

9—
Field
Coil
and Pole Shoe

10—Frame
11—
Insulating
Washer
12—
Washer

13— Nut
14
—Lockwasher

15—
Insulating
Bushing
16— Pole Shoe Screw
17—
Bearing,
Outer
18—
Drive
End
Frame
Pinion Housing
19— Intermediate Bearing Housing
20—
Lock
Washer 21—
Screw

22— Bendix Drive
23—
Thrust
Washer

24—Pin

25—
Armature

2 6—Commutator
27—
Thru
Bolt
28—
Insulator

29—
Bearing,
Intermediate
and
the armature rotated slowly by hand. If a
shorted coil is present, the steel strip
will
become
magnetized and
will
then vibrate.
H-101-
Field
Coils

Using
test
probes, check the field coils for both
ground and
open
circuits.

a.
To
test
for ground, place one probe on the motor frame or
pole
piece
and touch the other probe to the field coil terminals. If a ground is present, the
lamp
will
light.
b.
To
test
for
open
circuits, place the probes on
the field coil terminal and on an insulated brush.
If
the light,
does
not light, the coil is
open
circuited.
H-102.
Brush
Holder Inspection

Using
test
probes, touch the insulated brush holder with one probe and a convenient ground on the commutator end head with the other probe. If the
lamp lights, it indicates a grounded brush holder.
H-103.
Starting Motor Reassembly

Refer
to Fig. H-40 and H-41.

a.
When assembling absorbent bronze bearing
found in the end plate and drive end frame, always
use the proper arbor
designed
to
give
the proper
bearing fit. Soak the bearings in oil
before
assem­
bling in the bearing bore. Give the bearing
seats

a
light coating of oil.

Note:
At assembly, the outer pinion housing bear­
ing must be flush with the bearing bore on the inside of the housing; the intermediate bearing
must be flush with the bearing bore on the side
toward the armature.

b.
Brushes should be correctly installed and con­
nected as outlined in Par. H-98 in order to be sure
of proper starting motor efficiency.
c. Assemble the armature bearing plate and Bendix

Folo-Thru
Drive to the drive end frame.
Install
the two holding cap screws and lock washers. Tighten them securely. 205