Alternator: Service and Repair
Alternator Replacement1. Make sure you have the anti-theft code for the radio, then Write down the frequencies for the radio's preset buttons.
2. Disconnect the battery negative cable, then disconnect the positive cable.
3. Disconnect the 4P connector from the alternator.
Alternator Replacement:
4. Remove the terminal nut and BLK wire from the B terminal.
Alternator Replacement:
5. Loosen the through bolt, then loosen the adjustment lock bolt, and then the adjusting nut.
6. Remove the belt from the alternator.
7. Remove the adjustment lock bolt and the through bolt, then remove the alternator.
8. Install in the reverse order of removal.
9. Adjust the alternator belt tension (see page 23-105).
10. Enter the anti-theft code for the radio, then enter the customer's radio station presets.
Alternator Overhaul
NOTE: Do not remove the pulley unless the front bearing needs replacement.
Alternator Overhaul:
To loosen the pulley locknut, use the tools as shown. If necessary, use an impact wrench.
Rectifier Test
NOTE: The diodes are designed to allow current to pass in one direction while blocking it in the opposite direction. Since the alternator rectifier is made up of eight diodes (four pairs), each diode must be tested for continuity in both directions with an ohmmeter that has diode checking capability; a total of 16 checks.
1. Check for continuity in each direction, between the B and P, and between the E (ground) and P terminals of each diode pair. All diodes should have continuity in only one direction.
2. If any of the eight diodes fails, replace the rectifier assembly. (Diodes are not available separately.)
Alternator Brush Inspection
1. Remove the end cover, then take out the brush holder by removing its two screws.
2. Measure the length of the brushes with a vernier caliper.
Alternator Brush Length:
Standard: 10.5 mm (0.41 in)
Service Limit: 1.5 mm (0.06 in)
If the brushes are less than the service limit, replace the alternator brush assembly.
Rotor Slip Ring Test
1. Check the resistance between the slip rings. There should be 1.8-3.0 Ohms.
^ If resistance meets the specification, go to step 2.
^ If resistance does not meet the specification, replace the alternator.
2. Check that there is no continuity between the slip rings and the rotor or rotor shaft.
3. If the rotor fails either continuity check, replace the alternator.
Stator Test
1. Check that there is continuity between each pair of leads.
2. Check that there is no continuity between each lead and the coil core.
3. If the coil fails either continuity check, replace the alternator.
Alternator Belt Inspection and Adjustment
Deflection Method:
Alternator Belt Inspection And Adjustment:
Apply a force of 98 N (10 kgf, 22 lbf), and measure the deflection between the alternator and the crankshaft pulley.
Deflection: 9.0 - 11.5 mm (0.35 - 0.45 in)
NOTE: On a brand-new belt (one that has been run for less than five minutes), the deflection should be 5.5 - 7.0 mm (0.22 - 0.28 in) when first measured. If the belt is worn or damaged, replace it.
Belt Tension Gauge Method:
Alternator Belt Inspection And Adjustment:
Following the gauge manufacturer's instructions, attach the special tool to the belt, and measure the tension.
Tension: 390 - 540 N (40 - 55 kgf, 88 - 121 lbf)
NOTE: On a brand-new belt, (one that has been run for less than five minutes), the tension should be 830 - 1030 N (85 - 105 kgf, 187 - 231 lbf) when first measured. If the belt is worn or damaged, replace it.
If adjustment is necessary:
1. Loosen the through bolt and the adjusting lock bolt.
Alternator Belt Inspection And Adjustment:
2. Move the alternator by turning the adjusting nut to obtain the proper belt tension, then retighten the bolts.
3. Recheck the deflection or tension of the belt.