1953 JEEP CJ belt

'Jeep*
UNIVERSAL
SERIES
SERVICE
MANUAL

COOLING
SYSTEM

Contents

SUBJECT
PAR.

GENERAL
.G-l Antifreeze Solutions. .G-l6
Cylinder
Block.
..................
.G-8

Draining
Cooling System............... G-3

Engine
Overheating..
.................
.G-19
Fan
Belt.
......... .........
.G-18
Filling
Cooling System.................
G-2

Inhibited
Coolant Solution .G-l7

Temperature
Sending Unit.
...........
.G-l0

Thermostat
.........................
G-9

RADIATOR
.G-5
Radiator
and Heater Hoses.............
G-7
SUBJECT
PAR.

Radiator
Pressure
Cap.................
G-4

Radiator
Removal and Replacement..... G-6

WATER
PUMP.
. . .G-ll
Water
Pump Disassembly. .............G-13

Water
Pump Inspection.
..............
.G-12

Water
Pump Reassembly.
.............
.G-14

Water
Pump Removal and Replacement. .G-l5

SERVICE
DIAGNOSIS.
.G-20

SPECIFICATIONS
. .G-21

ANTIFREEZE
CHART.
..... ... .G-22

G-l. GENERAL
a.
The satisfactory performance of the Hurricane

F4
engine
is controlled to a great
extent
by the proper operation of the cooling system. The
engine

block is full length water jacketed which prevents
distortion of the cylinder walls. Directed cooling
and
large water holes, properly placed in the cylin­
der head gasket cause more water to flow past the
valve
seats
(which are the
hottest
parts of the

block)
and
carry
the heat away from the valves, giving positive cooling of valves and seats.

Minimum
temperature of the coolant is controlled by a thermostat mounted in the
outlet
passage of
the engine. When the coolant temperature is below
thermostat-rated temperature, the thermostat re­ mains closed and the coolant is directed through
the radiator-bypass
hose
to the water pump. When the thermostat opens, coolant flow is directed to
the top of the radiator. The radiator dissipates the
excess
engine
heat before the coolant is recirculated
through the engine.
The
cooling system is pressurized. Operating pres­
sure
is regulated by the rating of the radiator cap

which
contains a relief valve, b. The Dauntless V-6
engine
efficiency and per­formance is controlled to a great
extent
by proper
operation of the cooling system. The cooling system

does
more than cool the engine. It also directs
the flow of coolant to provide the
best
operating
temperature range for each part of the engine.

In
the Dauntless V-6
engine
coolant is forced by
the water pump into two main passages that run the length of the block on each side (Fig. G-l).
FIG.
G-1—COOLANT
FLOW
THROUGH
THE
DAUNTLESS
V-6
ENGINE

161

COOLING
SYSTEM

14263

FIG.
G-2—COOLING SYSTEM
COMPONENTS
V-6
ENGINE

1—
Radiator
Pressure Cap

2—
Hose
Clamp

3—
Radiator
Hose (Inlet-Upper)
4—
Radiator
Hose (Outlet-Lower) 5—
Bolt
6—
Water
Pump Assembly 7—
Cap
8—Thermostat
By-Pass Hose
g—Water Outlet
Elbow

10—
Gasket

11—
Thermostat
12—
Water
Pump Gasket

13—
Dowel
Pin
14—
Radiator
Shroud (Heavy Duty Cooling) 15—
Pulley

16—
Fan
Spacer
17—
Fan
and Alternator Belt

18—Fan

19—
Lockwasher

20—
Radiator

21—
Drain
Cock
From
these
main passages, the coolant flows around
the
full
length of each combustion chamber.

After
cooling the block, the coolant passes through
ports between the block and each cylinder head.
These
ports direct most of the coolant flow around the exhaust valve area to prevent hot exhaust
gases

from
overheating the exhaust ports.

From
the cylinder heads, the water passes into a
water
manifold between each of the heads and the

water
pump. If the thermostat is closed, the coolant
is ported back to the pump where it is recirculated

back
into the pump and into the engine. After the
coolant heats enough to open the thermostat, the coolant is directed from the water manifold through
a
hose
to the top of the radiator and then through
the radiator which acts as a heat exchanger to cool the fluid. The coolant is then ported through a
hose

from
the bottom of the radiator to the pump, which

recirculates
it back to the engine.

The
cooling system is pressurized. Operating pres­
sure
is regulated by a relief valve in the radiator

cap. The
heater inlet
hose
is connected to a port on
the right bank cylinder head. The outlet
hose
is connected to the heater adapter tube on the water

pump.

c.
It is recommended when using water for coolant
that the cooling system be flushed and checked for leaks twice a year, preferably in the
fall
before
antifreeze is added and in the spring when the antifreeze is drained.

Reverse
flushing
will
aid greatly in removing rust 162

'Jeep*
UNIVERSAL
SERIES
SERVICE
MANUAL

FIG.
G-8—TEMPERATURE SENDING UNIT- HURRICANE
F4
ENGINE
1—Temperature
Sending Unit

b.
Dauntless V-6 Engine.

The
thermo-couple coolant sending unit is mounted
in
the left
rear
area of the intake manifold and is
connected by a single wire to the dash unit of
the instrument cluster.

G-ll.
WATER PUMP

a.
Hurricane
F4 Engine.

The
water pump on the
Hurricane
F4
engine
is a

centrifugal
impeller type of large capacity to
cir­

culate water in the entire cooling system. The double row
ball
bearing (Fig. G-9), is integral with
the shaft and is packed at assembly with a special
high melting point grease which
will
last the life of
the bearing. The bearing is sealed to retain the
lubricant
and prevent
dirt
and dust from entering.

The
bearing and shaft are retained in the water
pump body by the bearing retaining wire. The
water
seal bears against the ground seat on the
pump body and the inside of the impeller, maintain­
ing a constant pressure against both and preventing

water
leakage. A
drain
hole
in the
bottom
of the
pump body precludes any water
seepage
past the

seal
from entering the bearing.
The
impeller and the pulley hub are pressed on
the shaft under high pressure,
b.
Dauntless V-6 Engine.

A
centrifugal-type water pump, shown in
Fig.
G-10,

circulates
coolant through the Dauntless V-6
engine

and
its cooling system.
This
pump is mounted on
the timing chain cover.
Similar
to the
engine
cooling
fan
mounted on its hub, the pump is driven through
a
V-belt from the crankshaft pulley.

Coolant
enters the water pump at its center.
Centri­

fugal force then forces coolant radially outward, through vanes of the pump impeller, and backward
through two discharge passages in the timing chain cover. These passages conduct an equal amount of
coolant to each cylinder bank water jacket.
This

water
pump has a sealed double row
ball
bearing
and
a ceramic water seal, neither of which can be

serviced.
In
event
of bearing or water seal failure, the entire water pump assembly must be replaced.
G-l2.
Water
Pump Inspection

Check
the water pump for leaks, and excessive end play or
looseness
of the shaft in the pump. A

quick
way to check is to work the fan blades up
and
down by hand. If any play is noticed, this
indicates that the bearings are rough. Rough bear­ings should be checked to see if the water pump
should be replaced or rebuilt.

G-13.
Water Pump
Disassembly
—
Hurricane
F4
Engine

•
Refer to Fig. G-9.

a.
Remove the fan belt, fan blades, and fan pulley.

b.
Remove the
bolts
attaching the water pump
to the block. Remove the pump.

c.
Remove the bearing retainer spring.

d.
Remove the pump impeller and pulley with a suitable puller.

e.
Remove the pump seal, bearing and shaft, and

bearing
slinger.

G-l4.
Water Pump Reassembly
—
Hurricane
F4
Engine

•
Refer to Fig. G-9.
Before assembling the water pump, examine water
seal
seat in the pump body and should it be rough,

install
a new pump body.

To
reassemble the unit, insert the long end of the shaft into the pump body from the front end until
the outer end of the bearing is flush against the

FIG.
G-9—WATER
PUMP-
HURRICANE
F4
ENGINE

1—
Fan
and Pump Pulley
2—
Bearing
and Shaft

3—
Bearing
Retainer Spring

A—Pipe
Plug 5—
Pump
Body
6—
Seal
Washer 7—
Pump
Seal
8—
Impeller

9—
Gasket
167

G
COOLING SYSTEM
12761

FIG.
G-10—WATER
PUMP—

CROSS-SECTIONAL
VIEW
—
DAUNTLESS
V-6
1—
Hub

2—
—Shaft
and Bearing
3—
Cover

4—
Impeller

5—
Ceramic
Seal
6—
Seal
Assembly front end of the pump body. Position the seal,

washer,
and pump seal on shaft flush against the ground seat in the water pump body. Place the

impeller
on an arbor press and press the long end
of the shaft into the impeller until the end of the shaft is flush with the hub of the impeller. Support
the assembly on the impeller end of the shaft and
press the pulley hub on the shaft until the shaft end is flush with the pulley hub. Move the shaft

in
the pump body to align the retaining wire
grooves
in the bearing and pump body and place
the bearing retaining wire in position.

G-l
5. Water Pump Removal and Replacement — Dauntless V-6 Engine

Drain
the cooling system. Remove the fan belt and remove the cooling fan and pulley from the hub on
the water pump. Disconnect the
hoses
from the
water
pump. Remove the cap screws that secure
the water pump to the timing chain cover; remove
the water pump. Do not disassemble the water

pump;
it is serviceable only as an assembly. When

replacing
the water pump, torque the water pump cap screws 6 to 8 lb-ft. [0,829 a 1,106 kg-m.].

G-16.
Antifreeze Solutions

When
water freezes it expands approximately 9%

in
volume. When water, confined in a cooling sys­
tem, freezes it exerts tremendous pressures causing
serious damage. To prevent freezing, antifreeze can
be added to the water to lower its freezing point.

The
two
types
of antifreeze commonly used today have either a methanol or ethylene glycol base,

and
contain corrosion inhibitors. The only anti­
freeze recommended for the cooling system of

'Jeep'
vehicles is ethylene glycol (permanent type).

Methanol
base antifreeze evaporates with the water
when the vehicle is operated at warmer tempera­
tures and requires more attention to avoid
loss
of
protection. Ethylene glycol base antifreeze seldom
evaporates at normal operating temperatures.

Methanol
solution is injurious to vehicle finishes.
Should
any be spilled on the vehicle, it should be
washed off immediately with a
good
supply of cold water without wiping or rubbing. Under ordi­

nary
conditions, ethylene glycol is not injurious to
vehicle finishes.

Warning.*
Drinking
ethylene glycol antifreeze or its
solutions can be harmful or fatal. Do not use anti­
freeze containers for
food
or beverages.

A
table in Par.
G-2
2
gives
the protection obtained
by the addition of various amounts cf ethylene glycol.
Before installing antifreeze, inspect the cooling sys­
tem to be sure it is clean, leak-proof, and otherwise

in
proper operating condition.
Drain
the cooling system, see Par. G-3. Pour in 3 quarts [3 ltr.] of

clean
water, add the required quantity of anti­ freeze, then add clean water to within 1" [2,54 cm.] of the top of the overflow pipe to allow for expan­
sion when hot. Run the
engine
until it is
warm.

Then
recheck the solution level.
Check
the anti­
freeze protection with a hydrometer reading.

G-l7.
Inhibited Coolant Solutions

All
'Jeep5 vehicles equipped with either the
Hur­
ricane
F4 or Dauntless V-6
engine
should use only

inhibited
year-round, permanent-type
engine
cool­
ant
solutions that are formulated to withstand two

full
calendar years of normal operation without

draining
or adding inhibitors. The
engine
cooling
system should be completely drained and the
rec­
ommended coolant installed every two years. Be-
fo
a
installing the permanent-type solution, inspect the cooling system to be sure it is clean, leakproof,

and
in proper operating condition.

Note:
Water alone, methanol, or alcohol-type anti­
freeze is definitely not recommended for 'Jeep*
Vehicles.

G-l8.
Fan Belt

The
fan, water pump, generator or alternator are
driven
by a V-belt. The drive of the V-belt is on
the side of the V. A fan belt that is too tight
will

cause
rapid
wear of the alternator or generator and
water
pump bearings. If the belt is too
loose,
it may
slip
preventing the water pump from properly cool­
ing the
engine
or the generator or alternator from
properly
charging the electrical
circuit.
Use fan belt
tension
gauge
Tool W-283 to properly adjust belt.

The
fan belt is properly adjusted when it can be
deflected Vi" [13 mm.] with strong thumb pres­

sure
applied midway
between
the fan and alter­

nator
pulleys.
Check
this adjustment and inspect the condition of the fan belt at each
engine
lubri-
168

'Jeep'
UNIVERSAL
SERIES SERVICE
MANUAL

G
cation period. It is
good
preventive maintenance to
replace a badly frayed, worn or cracked fan belt
before it breaks in operation.

To
replace the fan belt,
loosen
the attaching
bolts

at each generator or alternator brace-to-engine mounting and pivot the alternator or generator to­

ward
the
engine
to gain slack needed to install the new belt Remove the old belt. Position the new
belt over the fan pulley, over the crankshaft pulley,
then over the generator or alternator pulley.
Pull
the generator or alternator away from the
engine

until
belt tension is
firm.
Then tighten the generator

or
alternator mounting
bolts
and check the tension
as indicated above. Reset the generator or alternator as necessary for correct belt tension.
Finally,
torque
the generator or alternator mounting
bolts
25 to 35 lb-ft. [3,4 a 4,8 kg-m.].

Note:
On the Dauntless V-6
engine
when adjusting
the fan belt tension, the alternator mounting
bolts

should be torqued 30 to 40 lb-ft. [4,14 to 5,53

kg-m.].
If a fan belt tension
gauge
(W-283) is
avail­

able, proper tension should be 80 pounds [36,2 kg.].

G-l
9. Engine Overheating

An
engine
will
not be damaged by high coolant
temperatures unless the coolant boils. The pres­

surized
cooling system on the 'Jeep' vehicles raises the boiling point of the coolant solution. Should
overheating be encountered, and the fault is be­
lieved to be in the cooling system check for the
following:

a.
Proper coolant level. See
Filling
Cooling Sys­
tem Par. G-2.
b. Poor air flow.
Check
for dirty radiator core. (See Radiator Par. G-5).
Check
for faulty belt
pulley operation, worn or
loose
fan belt, or dam­ aged fan.
Clean,
repair, replace or adjust as neces­

sary.

c. Foaming coolant.
Check
for air leaks at water
pump,
hose
connection and filler cap. Tighten, re­

pair
or replace as necessary.

d.
Surging or "after boil".
Check
pressure cap and
replace if valves or gasket are faulty.
e.
External
leaks.
Check
the following for leaks:
Hoses and clamps, water pump, radiator, head gas­
ket, core plugs and drain cocks, as well as the cylin­ der head or block for
cracks.

f.
Internal
leaks.
Check
for faulty head gasket,
cracked
cylinder head or block.
g. Poor coolant flow.
Check
hose
condition, water pump, fan belt, and repair or replace as necessary. Inspect block for rust or scale, and clean and flush
the system, if necessary.

h.
Check
the temperature
gauge.
169

G
COOLING SYSTEM G-20.
SERVICE DIAGNOSIS

SYMPTOMS
PROBABLE REMEDY

Overheating:
Lack
of Coolant Refill radiator
Thermostat inoperative . Replace thermostat
Water
pump inoperative. Overhaul or replace
Incorrect
ignition or valve timing. Set
engine
timing
Excessive piston blowby Check pistons, rings and cylinder walls
Fan
belt
broken or badly worn Replace
belt

Radiator
clogged
Reverse flush and clean
Air
passages
in core
clogged
Clean with water and air pressure
Excessive carbon formation. Remove carbon from cylinder head(s) Muffler
clogged
or
bent
exhaust
pipe
Replace damaged part

Loss
of Cooling
Liquid:
Loose
hose
connections
Tighten
connections

Damaged
hose
Replace
hose

Leaking
water pump Overhaul or replace

Leak
in radiator Remove and repair
Leaky
cylinder head
gasket
Replace
gasket
Crack
in cylinder block. Small crack can be closed with
Radiator
or Block Sealer

G-21. COOLING SYSTEM SPECIFICATIONS

Radiator
Cap:
Relief
Pressure

Vacuum
Valve Release.
Thermostat:
Rating

Starts to Open

Fully
Open

Water
Pump:
Type.

Drive

Radiator:

Type

Cooling System Capacity: Without Heater

With
Heater..

Fan:
Number of Blades Diameter

Drive
Belt: Angle of V

Length
Width
HURRICANE
F4
7 and 15 psi. [0,5 kg-cm2 and 1,05 kg cm2]
lA to 1 psi. [0,04 a 0,07 kg-cm2]

190°F.
[87,8°C]
180°F.
[82°C]

202°F.
[94°C]

Centrifugal
V-Belt

Tube
8s Fin
11 qt. [10,4 ltr.] 12 qt. [11,5 ltr.]
15" [38 cm.]
38°

42%" [108 cm.] [1,74 cmJ
DAUNTLESS
V-6 15 psi. [1,05 kg-cm2]
1 psi. [0,07 kg-cm2]

190°F.
[87,8°C]
180°F.
[82°C]

202°F.
[94°C]

Centrifugal
V-Belt

Tube
& Fin
9 qt. [8.5 ltr.]
10 qt. [9,4 ltr.]
4

\SbA"
[39,7 cm.]

38°

43.92"
[111,5
cm.] Vg"
[0.952
cm.] G-22. ANTIFREEZE CHERT

Quarts
i
Quarts
Ethylene Glycol

U.S.
Imperial
Liters
Fahr.
Cent.

10-Quart
System

2
m
2

16°
-
8.8°

3
2V2
2%
4°

-15.5°

4
3H
-12°

-24.4°

5 4M -34°

-36.6°

6
5

5Vs
-62°

-52.2°

11-Quart
System

2 2

18° -
7.6°

3 2H
2%
8°

-13.3°

4
3%
-
6°

:
-21.10

5 4M 4M -23°

-30.5°

6
5

SVs
-47°

-43.8°

12-Quart
System

2
1 m 2 1

19° ;
- 7.2°

3
2*A
10°
!
-12.2°

4
I
3H
3M 0°
;
-17.7°

5 !
4M 4^ :
-15°

s
-26.1°

6 1 5
5%
-34°

-36.6°
170

'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
terminal
and bracket. Test lamp should not light.

If
it
does,
the
brush
is shorted and must be replaced,
b.
Connect one lead of an ohmmeter to field ter­

minal
and the other lead to insulated brush. Re­
sistance reading should be zero. Move brush and

brush
lead wire to make certain that the brush lead wire connections are not intermittent. Resist­
ance reading should not vary when brush and lead

wire
are being moved.

C.
Connect ohmmeter leads to bracket and grounded brush. Resistance reading should be zero.
Repeat same
test
on brush lead wire as described

in
step
b above.
FIG.
H-30—INSULATION
AND
CONTINUITY

TEST
POINTS
1^-Brackct

2—
Field
Terminal

3—
Grounded
Brush

4—
Insulated
Brush

H-76.
Rotor
In-Vehicle
Tests

a.
Reference Par. H-73, Fig. H-28.
b.
To check for a short circuit in the rotor wind­
ings, the alternator should be removed. Refer to

Par.
H-79 for rotor bench
tests.

H-77.
ALTERNATOR
BENCH
TESTS

When
the various
tests
given in
Par.
H-69 through
H-76 have determined a fault within the alternator itself, the alternator should be removed from the vehicle and the following
tests
given in
sequence

to isolate the trouble to a particular
component

of the alternator.
Note
that certain
tests
can be
performed after the alternator is removed and
before
it is disassembled.

H-78.
ALTERNATOR
REMOVAL
Note:
Brushes and isolation
diode
can be removed

from
alternator without removing unit from vehicle.

a.
Disconnect all lead connections at alternator.
b.
Remove nut and
bolt
at alternator support

bracket.
Remove nut, bolt, washer, and adjustment

bracket.
Remove belt from alternator pulley. The alternator is now free to be removed from the
vehicle.

H-79.
Rotor Tests
—
Bench

This
test
checks the condition of the rotor (field coil) for
open
or shorted field winding, excessively

worn
or sticky brushes, and
open
connections. It should be performed with the brush assembly in­
stalled in the alternator.

a.
The field coil is checked for a short circuit
by connecting a fully charged battery and an ammeter in series with the two slip rings.

A
rheostat is placed in series in the
circuit
to protect
the instruments and
components
of the alternator. Set rheostat to maximum resistance (40 ohms)

before
making connections.

b.
Slowly reduce resistance of rheostat to zero.

Then
take reading on ammeter. With full battery
voltage
applied to the field coil, the field current
of the 35-amp. alternator should be 1.7 to 2.3 amp.

Note:
The field current of the 40 and 55 amp.
alternator should be 1.8 to 2.4 amps with full battery
voltage
applied to the field coil.
c.
Turn
rotor by hand, noting reading. Rotating
rotor
will
indicate if brushes are making
good
elec­

trical
contact. A slight fluctuation of reading (0.2

amp.)
is to be expected.
If
field current is not within limits, inspect brushes

and
slip rings for
excessive
dirt, sticky, or broken
brushes, and bad connections.
Check
brush as­ sembly for short and continuity (Par. H-75). Make
same
test
to slip rings. Reinstall repaired or known
good
brush assembly and repeat
test.
If
the field current is
above
the maximum value
specified, it indicates that the field coil is either
shorted to rotor or field coil has shorted windings.
If
the field current is zero, it indicates that the field

coil
or coil-to-slip ring connection is open. If the field
current
is considerably
less
than the value
specified, it indicates a poor coil-to-slip ring con­ nection or poor brush-to-slip ring connection.

d.
To check continuity of the rotor, disconnect the
battery and connect an ohmmeter directly across
the field. Resistance
between
field terminal and ground terminal should be approximately 6 ohms.
If
resistance is high, field coil is shorted.

e.
If rotor is found to be
defective
in
above
tests,
repeat the
above
tests
when the rotor is removed

from
the alternator by connecting the
test
circuit
to rotor slip rings to ascertain findings.
Field
current

will
be approximately 0.2 amp. higher than the
maximum
value because of the normal brush-to-

slip-ring
contact resistance that reduces field
current
slightly. If the rotor is found to be de­
fective, it should be replaced.

H-80.
Alternator Disassembly

Refer
to Fig. H-31.

a.
Remove brush assembly by removing two tap­ ping screws and cover. Then pull the brush as- 198