Alternator: Service and Repair

Alternator Replacement

NOTE: The original radio has a coded theft protection circuit. Be sure to get the customer's code number before
- disconnecting the battery.
- removing the No. 32 (7.5 A) fuse from the under-hood fuse/relay box.
- removing the radio.

After service, reconnect power to the radio and turn it ON. When the word "CODE" is displayed, enter the customer's 5-digit code to restore radio operation.

1. Disconnect the negative cable, then disconnect the positive cable from the battery, and wait at least three minutes.
2. Disconnect the alternator connector from the alternator.

Alternator Replacement:

3. Remove the terminal nut and the WHT wire from the B terminal.
4. Remove the adjusting bolt and through bolt nut, then remove the alternator belt from the pulley.

Alternator Replacement:

5. Pull out the alternator through bolt, then remove the alternator.
6. If necessary, remove the mount bracket bolts, and the upper and lower mount brackets.
7. Install in the reverse order of removal.
8. Adjust the alternator belt tension after installation.

Alternator Overhaul

Alternator Overhaul:

Nippondenso

NOTE: It is not necessary to separate the pulley, drive end housing, and the rotor unless the front bearing needs replacement.

To loosen the pulley locknut, use 10 mm and 22 mm wrenches. If necessary, use an impact wrench.

Alternator Overhaul:

Mitsubishi

NOTE: It is not necessary to separate the pulley, drive end housing, and the rotor unless the bearings need replacement.

To loosen the pulley locknut, use a 22 mm box wrench, if necessary, an impact wrench.

Rectifier Removal

Alternator Disassembly:

1. Remove the four through bolts.

Rectifier Removal:

2. Heat the rear bearing seat with a 1,000 W hair drier for about five minutes (120 - 140° F, 50 - 60° C).

Separating The Alternator Case:

3. Separate the rear housing from the drive-end housing by inserting a flat tip screwdriver into the openings and prying them apart. Take care not to damage the stator with the tip of the screwdriver.

Rectifier Removal:

4. Separate the rear housing from the stator/rectifier assembly by removing the four screws and the terminal nut.

Rear Bearing Replacement

Removing The Alternator Rear Bearing:

Mitsubishi
1. Pull off the rear bearing.
^ Make sure the tips of the bearing puller jaws are thin enough to fit between the bearing and the slip rings.
^ Do not reuse the bearing.

Installing New Rear Bearing:

2. Use a hand press to install the new bearing. Apply pressure only on the inner race to avoid damaging the bearing.

Alternator Reassembly

Mitsubishi
1. Push the brushes in, then insert a pin or drill bit (about 1.8 mm diameter) to hold them there.
2. Heat the rear bearing seat in the rear housing. After heating, continue immediately with assembling before the rear bearing seat cools completely.

Alternator Reassembly:

3. Put the rear housing/stator assembly and drive-end housing/rotor assembly together, tighten the four through bolts, pull out the pin, and plug the brush access hole.
4. After assembling the alternator, turn the pulley by hand to make sure the rotor totates smoothly and without noise.

Alternator Brush Inspection

Nippondenso

CAUTION: When replacing the brushes, use only a rosin core type solder or solder joints will corrode.

1. Remove the end cover, then take out the brush holder by removing its two screws.

Alternator Brush Inspection:

2. Measure the length of the brushes with a vernier caliper.

Alternator Brush Length:
Standard : 10.5 mm (0.41 in)
Service Limit: 5.5 mm (0.22 in)

If the brushes are less than the service limit, replace the brush holder assembly.

Mitsubishi

CAUTION: When replacing the brushes, use only a rosin core type solder or solder joints will corrode.

1. Separate the drive-end housing from the rear housing.
2. Separate the rear housing from the stator/rectifier assembly by removing the four screws and the terminal nut from the rear housing.

Alternator Brush Inspection:

3. Measure the length of the brushes with a vernier caliper.

Alternator Brush Length:
Standard: 20.0 mm (0.79 in)
Service Limit: 5.0 mm (0.20 in)

Soldering The Brushes:

If the brushes are less than the service limit, replace them.

Rectifier Test

Nippondenso

NOTE:
^ The diodes are designed to allow current to pass in one direction while blocking the opposite direction. Each diode must be tested for continuity in both directions. Since the rectifier is made up of eight diodes, there are a total of 16 checks.
^ Use an ohmmeter capable of checking diodes.

Rectifier Test:

1. Check for continuity in each direction between
- the B and P terminals.
- E (ground) and the P terminals.
All diodes should have continuity in only one direction.
2. If any of the diodes fail, replace the rectifier assembly. (Diodes are not available separately).

Mitsubishi

NOTE:
^ The diodes are designed to allow current to pass in one direction while blocking the opposite direction. Each diode must be tested for continuity in both directions. Since the rectifier is made up of nine diodes, there are a total of 18 checks.
^ Use an ohmmeter capable of checking diodes.

Rectifier Test:

1. Check for continuity in each direction between
- the B and P terminals. the B' and P terminals.
- E (ground) and the P terminals.
All diodes should have continuity in only one direction.
2. If any of the diodes fail, replace the rectifier assembly. (Diodes are not available separately.)

Rotor Slip Ring Test
1. Check that there is continuity between the slip rings.

Rotor Slip Ring Test:

2. Check that there is no continuity between the slip rings and the rotor or rotor shaft.

If the rotor fails either continuity check, replace the alternator.

Stator Test
Nippondenso
1. Check that there is continuity between each pair of leads.

Stator Test:

2. Check that there is no continuity between each lead and the coil core.
3. If the coil core fails either continuity check, replace the alternator.

Mitsubishi
1. Check that there is continuity between each pair of leads.

Stator Test:

2. Check that there is no continuity between each lead and the coil core.
3. If the coil core fails either continuity check, replace the alternator.

Alternator Brush Inspection

Alternator Brush Inspection And Adjustment:

Deflection method:
Apply a force of 98 N (10 Kgf, 22 lbf) and measure the belt deflection between the alternator and the crankshaft pulley.

NOTE:
^ On a brand-new belt (one that has been run for less than five minutes), the deflection should be
*1 5.0 - 7.0 mm (0.20 - 0.28 in) or
*2 6.0 - 8.5 mm (0.26 - 0.33 in)
when first measured.
*1: B16A2 engine
*2: D16Y7, D16Y8 engines
^ If the belt is worn or damaged, replace it.

If adjustment is necessary:
1. Loosen the alternator adjusting bolt and the through bolt nut.
2. Move the alternator to obtain the proper belt tension, then retighten the adjusting bolt and the through bolt nut to the specified torques.
3. Recheck the deflection of the belt.

Alternator Brush Inspection And Adjustment:

Tension gauge method:
Following the gauge manufacturer's instructions, attach the special tool to the belt, and measure the tension.

NOTE:
^ On a brand-new belt (one that has been run for less than five minutes), the tension should be
*1 690 - 880 N (70 - 90 Kgf, 144 - 199 lbf) or
*2 540 - 740 N (55 - 75 Kgf, 121 - 165 lbf)
when first measured.
*1: B16A2 engine
*2: D16Y7, D16Y8 engines
^ If the belt is worn or damaged, replace it.

If adjustment is necessary:
1. Loosen the alternator adjusting bolt and the through bolt nut.
2. Move the alternator to obtain the proper belt tension, then retighten the adjusting bolt and the through bolt nut to the specified torques.
3. Recheck the tension of the belt.