Reverse Polarity Protector

4-39. Reverse Polarity Protector

a. Removal.

Caution: Disconnect the battery cable (6, fig. 4-1) from the positive battery terminal (4) before disconnecting

any other leads from the engine components. This will prevent shorts which could damage the alternator,

voltage regulator, and other parts.

(1) Disconnect the electrical leads from the reverse polarity protector. Tag leads to facilitate reassembly.

(2) Remove the two cap screws (20, fig. 431), nuts (21), and lock washers (22) that secure the reverse

polarity protector (23) to the mounting bracket; remove the reverse polarity protector.

b. Cleaning and Inspection.

(1) Wipe the exterior of the reverse polarity protector with a cloth dampened with cleaning solvent (fed. spec.

P-D-680) ; dry thoroughly.

(2) Inspect the reverse polarity protector for cracks, signs of overheating, loose or damaged terminals, and

other damage; replace a damaged polarity protector.

c. Installation. Installation of the reverse polarity protector is the reverse of removal. Refer to items 20 through 23

in figure 4-31. If necessary, refer to figure 1-3 for connection requirements.

4-40. Excitation Resistor

a. Removal.

Caution: Disconnect the battery cable (6, fig. 4-1) from the positive battery terminal (4) before disconnecting

any other leads from the engine components. This will prevent shorts which could damage the alternator,

voltage regulator, and other parts.

(1) Disconnect the electrical leads from the excitation resistor. Tag leads to facilitate reassembly.

(2) Remove the cap screw (24, fig. 4-31), nut (25), and lock washer (26) that secure the excitation resistor

(27) to the mounting bracket.

b. Cleaning and Inspection.

(1) Clean the excitation resistor with a cloth dampened with cleaning solvent (fed. spec. P-D680); dry

thoroughly.

(2) Inspect the excitation resistor for cracks, signs of overheating, loose or damaged terminals, and other

damage. Use a multimeter to check the resistance of the unit. Resistance must be 33

ohms. Replace the resistor if it is damaged or if resistance is in correct.

c. Installation. Installation of the excitation resistor is the reverse of removal. Refer to items 24 through 27 in

figure 4-31. If necessary, refer to figure 1-3 for connection requirements.

4-41. Engine Starter a. Removal.

Caution: Disconnect the battery cable (6, fig. 4-1) from the positive battery terminal (4) before

disconnecting any other electrical leads from the engine components. This will prevent shorts which could

damage the alternator, voltage regulator, and other parts.

(1) Disconnect the electrical leads to the starter solenoid switch (6, fig. 4-26).

(2) Remove the three cap screws and lock washers that secure the engine starter (7) to the engine side of the

flywheel housing; pull straight forward on the starter to remove the assembled starter solenoid switch and starter from the

engine.

b. Cleaning and Inspection.

(1) Clean the exterior of the engine starter with a cloth dampened with cleaning solvent (fed.

spec. - -680). Take care to prevent solvent from entering the starter.

(2) Inspect the starter for cracks, signs of overheating, loose solenoid switch mounting, damaged pinion teeth

on the drive, and other damage.

(3) Check the armature for free rotation. There must be no catching, binding, or scraping as the armature is

rotated.

(4) Check the starter brushes and replace if necessary (subparagraph c below).

(5) Bench test the starter as directed in subparagraph d below.

(6) Replace the starter if it fails to meet the inspection or testing requirements.

c. Starter Brush Replacement.

(1) Remove the thru bolts (1, fig. 4-34) that secure the commutator end frame (2) to the engine starter; pull

straight out on the end frame to disengage the end of the rotor shaft from the bushing in the end frame.

(2) Remove the support pins (3) to release the grounded brush holders (7), insulated brush holders (8), and

brush springs (4) from the brush supports (15). Remove the brush screws (5) that secure the brushes (6) to the brush

holders; remove the brushes.

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