TM 5-4240-501-14&PFig. 75 - Removing Thru BoltsCAUTION: Do not clamp the motor housing in a vise orstrike the motor housing with a hammer. These motorscontain two powerful ceramic magnets which can bebroken or cracked if the motor housing. is deformed ordented.Remove armature and end cap as shown in Fig. 76. (If120 volt motor, remove ground post with 1/4" nut driverto free rectifier assembly. Fig. 79.)Fig. 76 - Removing ArmatureClean all dirt or corrosion accumulations from thearmature, end cap, end head, etc. The bearings, motorhousing and armature should not be soaked in acleaning solution. The armature commutator may becleaned with a fine sand paper or commutator paper. Donot use emery cloth, as emery will embed in thecommutator and cause rapid brush wear. If it issuspected that the armature is defective, a new armatureshould be tried in the motor. If proper testing equipmentis available, check the suspected armature to determineif it is defective.Starter motor armatures have very low resistance,usually below detection on available multimeters (volt -ampere - ohm). To check for shorted armatures, a pieceof equipment known as a "growler" may be used.STARTERSGear Drive 12V & 120VThe brushes should be checked for poor seating, weakbrush springs, dirt, oil or corrosion. See Fig. 77.If the magnets are suspect, a new motor housing shouldbe tried to test motor performance (Figs. 72 and 73).Fig. 77 - Check BrushesCHECKING THE RECTIFIER ASSEMBLY 120 VACSTARTER MOTORDisconnect rectifier from end cap by removing leadsfrom terminals.Test rectifier with multimeter (VOA meter, page 8) set onresistance (R x 1 ohm) scale. Touch meter leads to redand black rectifier lead, then reverse meter leads andrecheck. The meter should indicate a reading in onedirection only. Touch meter leads to black rectifier leadshown in Fig. 79 and both AC posts, then reverse meterleads. The meter should show a reading in one directiononly. Touch meter leads to red rectifier lead and bothAC posts. then reverse meter leads. The meter shouldshow a reading in one direction only.If a meter reading is indicated in both directions or noreading is indicated in either direction, the rectifierassembly is defective and must be replaced.ASSEMBLY OF STARTER MOTORSWhen all parts have been thoroughly inspected, lightlylubricate the bearings with #20 oil, and reassemble in thefollowing manner.Insert the brushes in their respective holders. NOTE: Atool such as shown in Fig. 45 and 78 should be used tohold the brushes clear of the armature commutator whenassembling the armature to end cap.21
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