1. FIGURE 19-1 To test the voltage drop of the battery cable connection, place one voltmeter lead on the battery terminal and the other voltmeter lead on the cable end and crank the engine. The voltmeter will read the difference in voltage between the two leads which should not exceed 0.2 volt (200 mV).

2. FIGURE 19-2 Voltmeter hookups for voltage drop testing of a GM-type cranking circuit.

3. FIGURE 19-3 Voltmeter hookups for voltage drop testing of Ford-type cranking circuit.

4. FIGURE 19-4 A typical Ford solenoid on the left and a typical GM solenoid on the right.

5. FIGURE 19-5 GM solenoid ohmmeter check
FIGURE 19-5 GM solenoid ohmmeter check. The reading between 1 and 3 (S terminal and ground) should be 0.4 to 0.6 ohm (hold-in winding). The reading between 1 and 2 (S terminal and M terminal) should be 0.2 to 0.4 ohm (pull-in winding).

6. FIGURE 19-6 Starter trouble diagnostic chart.

7. FIGURE 19-7 Starter current can be measured by using a high current clamp and a digital multimeter or a specialized starting and charging tester.

8. FIGURE 19-8 Before disassembly of any starter, mark the location of the through bolts on the field housing. This makes reassembly easier.

9. FIGURE 19-9 Removing the solenoid from the starter on a GM-type starter assembly.

10. FIGURE 19-10 Rotate the solenoid to remove it from the starter housing
FIGURE Rotate the solenoid to remove it from the starter housing. (Caution: The plunger return spring exerts a force on the solenoid and may cause personal injury if not carefully released.)

11. FIGURE The brushes should be replaced if worn to less than 50% of their original length. Replace if less than 1/2 in.(13 mm) long.

12. FIGURE 19-12 An exploded view of a General Motors starter.

13. FIGURE To replace the starter drive unit, the retainer and clip must be removed from the armature shaft. A box-end wrench and a hammer can be used to pop the retainer off of the spring clip.

14. FIGURE 19-14 Measuring an armature shaft for run-out using a dial indicator V-blocks.

15. FIGURE 19-15 Using a growler to check for shorted armature windings.

16. FIGURE Replacement starter brushes should be installed so the beveled edge matches the rotation of commutator.

17. FIGURE A shim (or half shim) may be needed to provide the proper clearance between the flywheel teeth of the engine and the pinion teeth of the starter.

18. FIGURE This simple theft deterrent circuit will prevent the engine from cranking unless the lights are turned on first. The lights do not have to remain on after the engine starts.