Section XI. MAINTENANCE OF ELECTRICAL SYSTEM COMPONENTS
continuity check of electrical circuit. Repair or replace
defective wiring or terminals.
(2) Negative heat sink-rectifier test (fig. 4-
(1) The self-rectifying charging alternator
(a) The negative heat sink is
is designed to give long life and satisfactory service with
grounded to the housing by means of its mounting
a minimum amount of maintenance, but the following
screws and stud. Be sure that these screws are clean
precautions must be observed.
and tight so that the negative heat sink makes good
contact with the housing.
Caution: Do not make, or break, any
(b) Correct the negative lead of an
alternator connections while alternator is operation
ohmmeter to check point one and touch the positive lead
This would damage the voltage regulator.
to terminals 4, 5, and 6. A high resistance reading
should be obtained. If a low resistance reading is
obtained the diode is shorted. Replace the alternator.
battery being connected in circuit.
c. Alternator Replacement. Refer to figure 4-
Caution: When charging batteries from an
d. Alternator Belt Replacement.
external source of power, be sure battery is
connected from circuit before beginning charging
operation, to prevent damage to alternator rectifying
(2) Before removing alternator for repair
Reverse Current Polarity Protective Relay
replacement, inspect the drive belt, mounting brackets,
a. General. Since alternators are sensitive to
and wiring harness, in the following manner:
electric current polarity, incorrect wiring will cause the
(a) Check belts for proper tension,
diodes in the alternator to short out. To protect against
excess wear, or the presence of oil or grease which
this, a reverse current polarity protective relay is installed
could cause them to slip.
(b) Check pulleys for discoloration
which could indicate overheating due to belt slippage.
(1) Disconnect the three cannon-plug-type
Inspect pulleys for wear which could allow belts to
electrical connections to the reverse polarity relay.
bottom in the pulley grooves. Replace worn or defective
(2) Remove the two mounting capscrews
(c) Check mounting brackets and
Installation is reversed of
tension adjusting arm. Wear or looseness of these parts
will prevent proper belt adjustment and may result in
misalignment which will cause premature wear on belts,
Tighten replace parts as
a. Removal and Installation. Refer to figure 4-
(d) Inspect all wiring and terminals for
27 to remove or install the starting motor.
signs of wear, looseness, or corrosion. Check for worn
or frayed insulation which could result in shorts or
(1) At installation, add two or three drops
grounds. Clean and tighten all terminal connections.
of OE-30 lubricating oil in each oil reservoir.
(e) Check batteries. Take a specific
(2) Every 200 hours add at least 3 to 5
gravity reading on each cell. Replace batteries which
drops of OE-30 lubrication oil in each oil reservoir.
indicate one or more defective cells.
b. On-Equipment Test.