Jeep UNIVERSAL CJ-2A - Page 142

' Jeep' UNIVE RSA L an d 'Jeep' DISPATCHER
Brushes tha t ar e soldere d to the fi.el d coi l shoul d
be unsolder ed an d th e loo o m th e field coi l lea d
shoul d be op e ne d. I nse rt the new brush pigtai l to
it s full dep th in the loo p. Th e new brush lea d
shoul d be tig htly clinched in the te rmina l and the n
sol
dered to mak e a st ron g, low-resista nc e co nne c-
ti on.
1-52. Commutato r
Ch eck the com mu ta tor for we ar an d discoloration .
If the commutator is ro u gh or worn the armatur e
shou ld be removed and the co mmu tator t urn ed
do wn in a latn e.
1-53. Armatur e
V isua lly ins pect th e arma tu re for m echa nical
defects befor e checkin g for shor ted or grounde d
coils.
Us e a set of t es t probes for te s ti ng ar m at ur e
c ir cuits. To te st the ar m at ur es for gro un ds, tou ch
one poi nt of th e test p robe s to a co mmu tator
segm ent and to uch th e othe r point to the core or
shaf t. Do no t to uc h th e poin ts to t he bearin g
surfa ce or to the br u sh surfa ce as the arc forme d
will burn the smooth finis h. If the lamp lights , the
coil
connecte d to the co mmu tator segment is
grounde d .
To t est for shor ted a rmatur e coils, a growler as
shown in Fi g. 153 is necessary. Th e armatur e is
place d against th e core and a s te el strip is hel d
on the armature. The growler is th en energized and
the armature rotated slowly by hand. If a shorte d
coil
is present, the stee l strip will become magne -
tized and will then vibrat e.
1 -54 . Field Coil s
Using test probes , check the field coils for both
g roun d and open circuits. To test for ground,
place one probe on the motor frame or pole piece
and touch the oth er probe to the field coil ter minals .
If a ground is presen t, th e lamp will light .
To test for open circuits. place the probes on the
field coil terminal and on an insula t ed brush. If
the light does no t light , the coil is open circuited .
1-55. Bru sh Hold er In s pection
Using test probes, touch the insulated brush holder
with one probe and a convenient ground on the
co mmut ator end head with the oth er probe. If
the lamp lights, it indicates a groun ded brush
holder.
1-56. A sse mbly of Start i ng Motor
When assembling absorbent bronze bearings, al-
ways use th e proper arbor designed to give the
proper bearing fit. Soak the bearing in oil before
assembl in g in the bearing bor e.
Brushes should be correctly installed and connected
as outlined in Par. I-50 in order to be sure of proper
starting motor efficiency.
Soak the bearings in oil and give the bearing seats
a light coating of oil.
1-57. Bench Test
The motor should first be checked to see that the
free runnin g volt ag e and c ur rent are within s pe ci fi -
ca tions. T o tes t, c onnec t the moto r to a ba tt er y.
amme t er an d vol tmeter. If the c urren t is too high
check the bearing al ignmen t and end play to ma ke
su re th ere is no bi nding or in terfere nc e. Using a
sp ri ng scale and torqu e arm check t he s tall t orqu e
to s ee that t he moto r is prod uc in g i ts ra te d cr an k-
ing power . Th e stall t or que wi ll be the produc t of
the sprin g scale re ading and th e lengt h of th e ar m
in feet.
If th e to rque is n ot up to sp ec ifications
check the s eati ng of the b rushe s on th e com mu ta tor
and the in te rna l conne ct ion of the mo tor f or hi gh
res istanc e. The Ben dix Driv e shou ld be che ck ed for
c or rec t opera tion. Th e B endix pinio n shoul d be
check ed to see tha t it shi fts w hen the m otor is
operate d un der no loa d
1- 58_ Bendix Starte r Drive
• Mod el CJ-2 A
Th e B endix t yp e fly wn ee l drive Fi g. 158, us ed Oh
Mode l CJ-2A is design ed so tha t as th e s tart in ":
m otor is en ergized , cen tr ifugal force sends the cour . .
terweighted gear into en g agemen t with the teeth on
the flywheel. When t he e ngin e s ta rts and the speed
of the e ngin e ex ceeds the co mparabl e s pee d of the
st artin g mo tor, th e drive pinion is forced out c:i
engagemen t with th e fly wh eel.
FIG. 158- ST ARTING MOTOR BENDIX DRIVE
The Bendix spring absorbs the shock of engage -
men t. There are two types of Bendix drives an d
springs: right hand and left hand. The type use d
on these m odels is of the right hand type.
To determine a right or left hand Bendix drive,
turn the drive pinion so the threads on the shaft
will show. Hold the end of shaft toward you and
note spiral of thread: right hand spiral, right hand
drive, left hand spiral, l eft hand drive.
To determine a righ t or left hand sp ring, note the
spiral of the coil: if to the right, it is a right hand
spring - if to the left, it is a left hand sprin g.
If the Bendix drive spring shows signs of being
distorted, a new spring should be installed.
Do not lubricate the Bendix drive sleeve. Wash it
thoroughly with a suitable solvent and install it
dry but be sure it is clean.
1-59. Overrunning Clutch Drive
• Early Model C]-3A
Starting motors used on early Mod els CJ -3A are
eq uip ped with the overrunning clutch type drive,
Fig. 159. In this drive the cl utch and pinion slides
on companion splines and the pinion is manually
engaged, with the flywheel teeth , by the starting
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