Starter Motor: Disassembly

1. Remove starter. See Figure and Figure . Remove starter through-bolts. Remove commutator end frame/brush holder assembly. See Fig 2 . Inspect brushes, pop-out springs and brush holders for wear and damage. Replace assembly, if necessary.
   NOTE: This test should be made for each ground or insulated brush to ensure continuity through both brushes and leads. See Fig 3 . If lamp fails to light, field coil is open and will require replacement.
2. For only those starters having a shunt coil connection, use a test lamp, placing one lead on shunt coil terminal while connecting other lead to a ground brush or an insulated brush. See Fig 4 . When testing a series coil for ground. separate series and shunt coil strap terminals during test. With strap terminals not touching case or other ground, using a test lamp, place one lead on grounded brush holder and other lead on either insulated brush. If lamp is lit, a grounded series coil is indicated and must be repaired or replaced. Test for an open circuit on each insulated brush by placing one lead on series coil terminal and other lead on insulated brush.
3. If test lamp is not lit, series coil is open and will require repair or replacement. Check armature to see if it turns freely. See Fig 5 . If armature does not turn freely, break down assembly immediately, Otherwise, give armature a no-load test. See Fig 6 .
   NOTE: Complete testing in a minimum amount of time to prevent overheating and damaging solenoid.
   NOTE: If specified current draw does not include solenoid, deduct from armature reading specified current draw of solenoid hold-in winding. To begin no-load test, close switch and compare rpm, current, and voltage readings with specifications. Make disconnections only with switch open. Use test results as follows: Rated current draw and no-load speed indicate a normal condition for starter motor.
4. Low rpm combined with high current draw is an indication of excessive friction caused by tight, dirty, or worn bearings; a bent armature shaft; a shorted armature; or shorted field coils. Failure to operate with high current draw indicates a direct ground in terminal or fields, or "frozen" bearings. Failure to operate with no current draw indicates an open field circuit, open armature coils, broken brush springs, worn brushes, high insulation between commutator bars, or other causes which would prevent good contact between brushes and commutator. Low no-load speed and low current indicate high internal resistance and high current draw, which usually mean shorted fields. Remove solenoid assembly screws. See Fig 7 . Remove field connector nut. See Fig 8 . Disconnect field connector. Rotate solenoid 90 degrees and remove it along with plunger return spring.
   NOTE: If solenoid is not removed from starting motor, connector strap terminals must be removed from terminal on solenoid before making testing.
5. Test solenoid windings by checking current draw. Check hold-in windings by connecting an ammeter in series with a 12-volt battery, switch terminal, and to ground. Connect carbon pile across battery. Adjust voltage to 10 volts. Ammeter reading should be 13-19 amps.
   NOTE: Current will decrease as windings heat up. Current draw readings that are over specifications indicate shorted turns or a ground in windings of solenoid. Both conditions require replacement of solenoid. Current draw readings that are under specifications indicate excessive resistance. No reading indicates an open circuit.
6. Check both windings, connecting them according to preceding test. Ground solenoid motor terminal. Adjust voltage to 10 volts. Ammeter reading should be 59-79 amps. Check connections and replace solenoid, if necessary. Slide field frame with enclosed armature assembly away from starter assembly. See Fig 9 . Remove shield. Separate field frame from armature. See Fig 10 . Inspect shaft, bearing, and pinion for discoloration, damage, or wear. Replace, if necessary. Inspect armature commutator. If commutator is rough, it should be turned down. Outside diameter of commutator must measure at least 41.91 mm (1.650") after it is undercut or turned. Do not turn out-of-round commutators.
7. Inspect points where armature conductors join commutator bars. Make surely have a good connection. A burned commutator bar is usually evidence of a poor connection. If test equipment is available, check armature for short circuits by placing it on a growler, and holding back a saw blade over armature core while armature is rotated. If saw blade vibrates, replace armature. Recheck armature after cleaning between commutator bars. If saw blade vibrates, replace armature. Remove gears, bushings, and washer. See Fig 12 . Remove cushion and driveshaft assembly from starter housing. See Fig 13 .
8. Disassemble driveshaft assembly by first separating needle bearing from driveshaft. Remove collar and locking ring from groove in driveshaft. Remove pinion stop and drive from driveshaft. See Fig 14 . Remove gear support from driveshaft. See Fig 15 . If not done in previous steps, remove screws that hold solenoid assembly into housing, and remove nut from field coil connector. Rotate solenoid 90 degrees and remove it along with return spring. See Fig 16 . Remove plunger with boot and shift lever assembly. See Fig 17 . Test solenoid windings,
   NOTE: Pinion clearance must be correct to prevent buttons on shift lever yoke from rubbing on clutch collar during cranking.
9. When starter motor is disassembled and solenoid is replaced, it is necessary to check pinion clearance. Disconnect motor field coil connector from solenoid motor terminal and carefully insulate connector. Connect one 12-volt battery lead to solenoid switch terminal and other to starter frame. Flash a jumper lead momentarily from solenoid motor terminal to starter frame, allowing shifting of pinion in cranking position, where it will remain until battery is disconnected. See Fig 18 .
   NOTE: A means for adjusting pinion clearance is not provided on starter motor. If clearance does not fall within limits, check for improper installation and replace all worn parts.
10. Push pinion back as far as possible to take up any movement, and check clearance with a feeler gauge. Clearance should be .25-3.56 mm (.01-.14").