1. Remove the generator from the vehicle (see "Removal and installation the generator").
2. Remove the generator pulley from the rotor shaft (see "Replacing the generator pulley")...
3. ...and a spacer sleeve.
4. Mark the relative positions of the stator and generator covers.
5. Press the four latches...
6. ...and remove the generator protective cover.
7. Using the TORX E4 key, unscrew the five bolts securing the voltage regulator with the brush assembly and the rectifier unit to the front cover.
8. Remove the voltage regulator with the brush assembly.
Note: This is what the voltage regulator with brush assembly looks like when removed from the generator.
9. Check the protrusion of the brushes in a free state. If the dimension H is less than 2 mm, replace the brushes or the brush unit as a whole. Check the ease of movement of the brushes in the brush holder. If they jam, the brush unit must also be replaced.
10. Unsolder the three stator winding leads from the rectifier unit...
11. ...and remove the rectifier block.
Note: This is what the removed rectifier unit looks like from the side of the protective casing...
...and from the stator side.
12. Using the TORX E8 key, unscrew the four tie bolts.
13. Press the front cover off the rotor shaft bearing...
14. ...and take it off.
15. Inspect the front cover. The plastic bushing of the rear bearing of the generator rotor should be tightly installed in the hole of the cover. If the bearing is correctly seated in the bushing, there should be no traces of the outer bearing ring slipping on it. If cracks are found in the cover, especially in the places where the generator is attached, it is necessary to replace the cover with a new one.
16. Carefully pry the stator with a screwdriver and separate the stator and the back cover.
17. Press the rotor shaft out of the rear cover bearing...
18. ...and separate the rotor and cover.
19. Inspect the rear cover. If, when rotating the bearing, you feel play between the rings, rolling or jamming of the rolling elements, the protective rings are damaged or there are grease leaks, replace the bearing. If cracks are found in the cover, especially in the places where the generator is attached, it is necessary to replace the cover with a new one.
20. To replace the front rotor shaft bearing, press it out of the cover.
21. Press the new bearing into the cover using a mandrel of suitable diameter, applying force to the outer ring,
22. Remove the spacer ring from the rotor shaft...
23. ...and the fan impeller.
24. Inspect the fan impeller. It should not have any mechanical damage, all blades should be positioned at the same angle to the plane of rotation. Otherwise, replace the impeller
25. Inspect the contact rings. If they have burrs, scratches, marks, wear marks from brushes and other damage, the rings must be ground. If the damage to the rings cannot be removed with sandpaper, you can turn the rings on a lathe, removing a minimum layer of metal, and then grind them.
26. Check the ease of rotation of the bearing from the contact rings. If, when rotating the bearing, there is play between the rings, rolling or jamming of the rolling elements, damage to the protective rings or grease leaks, the bearing should be replaced. To do this...
27. ...press the bearing from the rotor shaft journal...
28. ...and remove the bearing from the shaft and the protective washers.
29. Press the new bearing onto the rotor shaft until it stops against the shaft flange, applying force to the inner ring of the bearing through a mandrel of suitable diameter.
30. Check the rotor winding resistance with a tester by connecting it to the contact rings. The resistance should be approximately 3-5 Ohms. If the tester shows infinity, then there is a break in the rotor winding - the rotor must be replaced.
31. Check for a short circuit between the rotor winding and the housing by connecting the tester leads to any slip ring and the rotor housing. The tester should show infinity.
32. Check the stator winding for breakage by measuring the resistance between all winding terminals one by one with a tester. If the measured resistance tends to infinity, the stator must be replaced.
33. Connect the tester probes to the stator housing and to each winding terminal in turn. The measured resistance should be very high (tends to infinity). Otherwise, replace the stator.
34. Check the "positive" diodes by connecting the "negative" (black) probe of the tester to the "plus" terminal of the generator, and the "positive" (red) probe alternately connecting to the three contact terminals of the diodes. If the diodes are in good condition, the tester will show 700-800 Ohms.
35. Connect the "positive" (red) probe of the tester to the "plus" terminal of the generator, and connect the "negative" (black) probe alternately to the same three contact terminals of the diodes. If the diodes are in good condition, the tester will show infinite resistance.
36. Check the "minus" diodes by connecting the "negative" (black) probe of the tester to the "minus" terminal of the rectifier unit, and the "positive" (red) probe alternately connecting to the three contact terminals of the diodes. If the diodes are in good condition, the tester will show infinite resistance.
37. Connect the "positive" (red) probe of the tester to the "minus" terminal of the rectifier unit, and connect the "negative" (black) probe alternately to the same three contact terminals of the diodes. If the diodes are in good condition, the tester will show 700-800 Ohm.
38. If the tester shows low or close to zero resistance, the diode is "broken"; if the tester reading tends to infinity regardless of the color of the connected probes, the diode is "open". In both cases, the rectifier unit must be replaced.
39. Assemble the generator in the reverse order of disassembly, orienting the generator covers and stator according to the previously made marks.
(The text of the article was obtained from the website ChevyMan.ru)