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If the cranking system is not functioning properly, check the following to determine which part of the system is at fault:

Batteries– Verify the condition of the batteries, cables, connections and charging circuit.

Wiring– Inspect all wiring for damage or loose connec- tions at the keyswitch, magnetic switches, solenoids and cranking motor(s). Clean, repair or tighten as required.

If the above inspection indicates the starter motor to be the cause of the problem, remove the motor and perform the following tests prior to disassembly to determine the condition of the motor and solenoid and repairs required.

Preliminary Inspection

1. Check the starter to be certain the armature turns freely.

a. Insert a flat blade screwdriver through the opening in the nose housing.

b. Pry the pinion gear to be certain the armature can be rotated.

2. If the armature does not turn freely, the starter should be disassembled immediately.

3. If the armature can be rotated, perform the No- Load Test before disassembly.

No-Load Test

Refer to Figure 2-2 for the following test setup.

Be certain switch is open before connections or disconnections are made during the following pro- cedures.

1. Setup the motor for test as follows:

a. Connect a voltmeter from the motor terminal to the motor frame.

b. Use an RPM indicator to measure armature speed.

c. Connect a carbon pile across one battery to limit battery voltage to 20 VDC.

Do not apply voltages in excess of 20 volts. Exces- sive voltage may cause the armature to throw windings.

d. Connect the motor and an ammeter in series with two fully charged 12 volt batteries. e. Connect a switch in the open position from the

solenoid battery terminal to the solenoid switch terminal.

2. Close the switch and compare the RPM, current, and voltage reading to the following specifica- tions:

• RPM: 5500 Minimum to 7500 Maximum • AMPS: 95 Minimum to 120 Maximum • VOLTS: 20 VDC

Interpreting Results of Tests

1. Rated current draw and no-load speed indicates normal condition of the cranking motor.

2. Low free speed and high current draw indicates: a. Too much friction; tight, dirty, or worn bearings,

bent armature shaft or loose pole shoes allow- ing armature to drag.

b. Shorted armature. This can be further checked on a growler after disassembly.

c. Grounded armature or fields. Check Further after disassembly.

FIGURE 2-2. NO-LOAD TEST CIRCUIT

3. Failure to operate with high current draw indi- cates:

a. A direct ground in the terminal or fields. b. “Frozen” bearings (this should have been de-

termined by turning the armature by hand). 4. Failure to operate with no current draw indicates:

a. Open field circuit. This can be checked after disassembly by inspecting internal connec- tions and tracing circuit with a test lamp. b. Open armature coils. Inspect the commutator

for badly burned bars after disassembly. c. Broken brush springs, worn brushes, high in-

sulation between the commutator bars or other causes which would prevent good contact be- tween the brushes and commutator.

5. Low no-load speed and low current draw indi- cates:

a. High internal resistance due to poor connec- tions, defective leads, dirty commutator and causes listed under Number 4.

6. High free speed and high current draw indicates shorted fields. If shorted fields are suspected, replace the field coil assembly and check for improved performance.

Disassembly

Normally the cranking motor should be disassembled only as far as necessary to repair or replace defective parts.

1. Note the relative position of the solenoid (53, Figure 2-3), lever housing (78), nose housing (69), and C.E. frame (1) so the motor can be reassembled in the same manner.

2. Disconnect field coil connector (42) from solenoid motor terminal, and lead from solenoid ground terminal.

3. Remove the brush inspection plates (52), and brush lead screws(15).

4. Remove the attaching bolts (34) and separate the commutator end frame (1) from the field frame (35).

5. Separate the nose housing (69) and field frame (35) from lever housing (78) by removing attach- ing bolts (70).

6. Remove armature (45) and drive assembly (71) from lever housing (78).

7. Separate solenoid (53) from lever housing by pulling apart.

Cleaning and Inspection

1. The drive (71), armature (45) and fields (46) should not be cleaned in any degreasing tank, or with grease dissolving solvents, since these would dissolve the lubricant in the drive and dam- age the insulation in the armature and field coils. 2. All parts except the drive should be cleaned with

mineral spirits and a clean cloth.

3. If the commutator is dirty, it may be cleaned with No. 00 sandpaper.

NOTE: Never use emery cloth to clean commutator.

4. Inspect the brushes (13, Figure 2-3) for wear. a. If worn excessively when compared with a new

brush, they should be replaced.

b. Make sure the brush holders (10) are clean and the brushes are not binding in the holders. c. The full brush surface should ride on the com-

mutator to give proper performance. Check by hand to insure that the brush springs (16) are giving firm contact between the brushes (13) and commutator.

d. If the springs (16) are distorted or discolored, they should be replaced.

Armature Servicing

If the armature commutator is worn, dirty, out of round, or has high insulation, the armature (45) should be put on a lathe and the commutator turned down. The insulation should then be undercut 0.031 in. (.79 mm) wide and 0.031 in. (.79 mm) deep, and the slots cleaned out to remove any trace of dirt or copper dust. As a final step in this procedure, the commutator should be sanded lightly with No. 00 sandpaper to remove any burrs left as a result of the undercutting procedure.

The armature should be checked for opens, short circuits and grounds as follows:

1. Opens are usually caused by excessively long cranking periods. The most likely place for an open to occur is at the commutator riser bars. Inspect the points where the conductors are joined to the commutator bars for loose connec- tions. Poor connections cause arcing and burning of the commutator as the cranking motor is used. If the bars are not too badly burned, repair can often be effected by resoldering or welding the leads in the riser bars (using rosin flux), and turning down the commutator in a lathe to remove the burned material. The insulation should then be undercut.

2. Short circuits in the armature are located by use of a growler. When the armature is revolved in the growler with a steel strip such as a hacksaw blade held above it, the blade will vibrate above the area of the armature core in which the short circuit is located. Shorts between bars are sometimes pro- duced by brush dust or copper between the bars. These shorts can be eliminated by cleaning out the slots.

3. Grounds in the armature can be detected by the use of a 110-volt test lamp and test points. If the lamp lights when one test point is placed on the commutator with the other point on the core or shaft, the armature is grounded. Grounds occur as a result of insulation failure which is often brought about by overheating of the cranking motor produced by excessively long cranking pe- riods or by accumulation of brush dust between the commutator bars and the steel commutator ring.

Field Coil Checks

The field coils (46, Figure 2-3) can be checked for grounds and opens by using a test lamp.

1. Grounds— The ground connections must be disconnected during this check. Connect one lead of the 110 volt test lamp to the field frame (35) and the other lead to the field connector (42). If the lamp lights, at least one field coil is grounded and must be repaired or replaced.

2. Opens—Connect test lamp leads to ends of field coils (46). If lamp does not light, the field coils are open.

FIGURE 2-3 CRANKING MOTOR ASSEMBLY

1. C.E. Frame 2. Washers 3. O-Ring 4. Insulator 5. Support Plate 6. Brush Plate Insulator 7. Washers 8. Plate & Stud 9. Plate 10. Brush Holder 11. Lock Washer 12. Screw 13. Brush (12 req’d) 14. Lock Washer 15. Screw 16. Brush Spring 17. Screw 18. Screw 19. Screw 20. Lock Washers 21. Plate 22. Brush Holder Insulator 23. Screw 24. Lock Washer 25. Washer 26. O-Ring 27. Bushing 28. Insulator 29. Washer 30. Lock Washer 31. Nut 32. Nut 33. Lock Washer 34. Screw 35. Field Frame 36. Stud Terminal 37. Bushing 38. Gasket 39. Washers 40. Washer 41. Nut 42. Connector 43. Lock Washer 44. Nut 45. Armature

46. Field Coil (6 Coils) 47. Shoe 48. Insulator 49. Screw 50. Washer 51. O-Ring 52. Inspection Plug 53. Solenoid Housing 54. Lock Washer 55. Screw 56. Plunger 57. Washer 58. Boot 59. Washer 60. Spring 61. Retainer 62. Snap Ring 63. Shift Lever 64. Nut 65. O-Ring 66. O-Ring 67. Snap Ring 68. Lever Shaft 69. Drive Housing 70. Screw 71. Drive Assembly 72. Gasket 73. Plug 74. Gasket 75. Brake Washer 76. Screw 77. Lock Washer 78. Lever Housing 79. Washer 80. O-Ring

FIGURE 2-3. CRANKING MOTOR ASSEMBLY

Field Coil Removal

Field coils can be removed from the field frame assem- bly by using a pole shoe screwdriver. A pole shoe spreader should also be used to prevent distortion of the field frame. Careful installation of the field coils is necessary to prevent shorting or grounding of the field coils as the pole shoes are tightened into place. Where the pole shoe has a long lip on one side and a short lip on the other, the long lip should be assembled in the direction of armature rotation so it becomes the trailing (not leading) edge of the pole shoe.

Solenoid Checks

A basic solenoid circuit is shown in Figure 2-4. Sole- noids can be checked electrically using the following procedure.

Test

1. With all leads disconnected from the solenoid, make test connections as shown to the solenoid, switch terminal and to the second switch terminal “G”, to check the hold-in winding (Figure 2-5). 2. Use the carbon pile to decrease the battery volt-

age to 20 volts. Close the switch and read current. a. The ammeter should read 6.8 amps maximum. 3. To check the pull-in winding, connect from the solenoid switch terminal “S” to the solenoid motor “M” or “MTR” terminal (Figure 2-6).

FIGURE 2-4. SIMPLIFIED SOLENOID CIRCUIT

FIGURE 2-5. SOLENOID HOLD-IN WINDING TEST

FIGURE 2-6. SOLENOID PULL-IN WINDING TEST

To prevent overheating, do not leave the pull-in winding energized more than 15 seconds. The current draw will decrease as the winding tempera- ture increases.

4. Use the carbon pile to decrease the battery volt- age to 5 volts. Close the switch and read current. a. The ammeter should read 9.0 to 11.5 amps.

NOTE: High readings indicate a shorted winding. Low readings indicate excessive resistance.

6. To check for grounds, move battery lead from “G” (Figure 2-5) and from “MTR” (Figure 2-6) to the solenoid case. Ammeter should read zero. If not, the winding is grounded.

Assembly

Lubricate all bearings, wicks and oil reservoirs with SAE No. 20 oil during assembly.

Bearing Replacement:

1. If any of the bronze bearings are to be replaced, dip each bearing in SAE No. 20 oil before press- ing into place.

2. Install wick, soaked in oil, prior to installing bear- ings.

3. Do not attempt to drill or ream sintered bearings. These bearings are supplied to size. If drilled or reamed, the I.D. will be too large and the bearing pores will seal over.

4. Do not cross-drill bearings. Because the bearing is so highly porous, oil from the wick touching the outside bearing surface will bleed through and provide adequate lubrication.

5. The middle bearing is a support bearing used to prevent armature deflection during cranking. The clearance between this bearing and the armature shaft is large compared to the end frame bear- ings.

Motor Assembly:

1. Install the end frame (with brushes) onto the field frame as follows:

a. Insert the armature (45, Figure 2-3) into the field frame (35). Pull the armature out of the field frame just far enough to permit the brushes to be placed over the commutator. b. Place the end frame (1) on the armature shaft.

Slide end frame and armature into place against the field frame.

c. Insert screws (34) and washers (33) and tighten securely.

2. Assemble lever (63) into lever housing (78) If removed.

3. Place washer (79) on armature shaft and install new O-ring (80). Position drive assembly (71) in lever (63) in lever housing. Apply a light coat of lubricant (Delco Remy Part No. 1960954) on washer(75) and install over armature shaft. Align lever housing with field frame and slide assembly over armature shaft. Secure with screws (76) and washers (77).

4. Assemble and install solenoid assembly through lever housing and attach to field frame. Install nut (64) but do not tighten at this time. Install brush inspection plugs (52).

5. Using a new gasket (72), install drive housing (69) and secure with screws (70).

6. Assemble field coil connector (42) to solenoid. 7. Adjust pinion clearance per instructions on the

following page.

8. After pinion clearance has been adjusted, install gasket (74) and plug(73).

FIGURE 2-7. PINION CLEARANCE CHECK CIRCUIT

Pinion Clearance

To adjust pinion clearance, follow the steps listed below.

1. Make connections as shown in Figure 2-7. 2. Momentarily flash a jumper lead from terminal

“G” to terminal “MTR”. The drive will now shift into cranking position and remain so until the batteries are disconnected.

3. Push the pinion or drive back towards the com- mutator end to eliminate slack movement. 4. The distance between the drive pinion and hous-

ing should be between .330 in. to .390 in. (8.3 mm to 9.9 mm) as shown in Figure 2-8.

5. Adjust clearance by turning shaft nut (64, Figure 2-3).