Overhaul

This procedure includes testing individual parts of the alternator as the unit is disassembled.

NOTE: Alternator charging circuit -- The ignition warning light is connected in series with the alternator field circuit. Bulb failure would prevent the alternator charging, except at very high engine speeds, therefore, the bulb should be checked before suspecting an alternator failure.

Precautions
- Battery polarity is NEGATIVE GROUND, which must be maintained at all times.
- No separate control unit is fitted; instead a voltage regulator of micro-circuit construction is incorporated on the slip ring end bracket, inside the alternator cover.
- Battery voltage is applied to the alternator output cable even when the ignition is switched off, the battery must be disconnected before commencing any work on the alternator. The battery must also be disconnected when repairs to the body structure are being carried out using electric welding equipment.

Alternator Connections:

Sequence of connections
1. Suppression capacitors (two)
2. Positive suppression terminal
3. ND terminal
4. + output terminal
5. Sensing terminal

DISASSEMBLY & TESTING

1. Withdraw the connectors from the alternator.
2. Remove the alternator.

Alternator Cover:

3. Disconnect the suppressor and remove the alternator cover.
4. Disconnect the lead and remove the rectifier assembly.
5. Note the arrangement of the brush box connections and remove the screws securing the regulator to the brush box and withdraw. This screw also retains the inner brush mounting plate in position.
6. Remove the screw retaining the outer brush box in position and withdraw both brushes.
7. Check brushes for wear by measuring length of brush protruding beyond brush box moulding. If length is 10mm (0.4 in) or less, fit new brushes.
8. Check that brushes move freely in holders. If brush is sticking, clean with a mineral spirit moistened cloth or polish sides of brush with fine file.
9. Check brush spring pressure using push.type spring gauge. Gauge should register 136-279g (5-10 oz) when brush is pulled back until face is flush with housing. If reading is outside these limits, fit a new brush assembly.
10. Remove the two screws securing the brush box to the slip ring end bracket and lift off the brush box assembly.
11. Securely clamp alternator in a vice and release the stator winding cable ends from the rectifier by applying a hot soldering iron to the terminal tags of the rectifier. Pry out the cable ends when the solder melts.
12. Remove the two remaining screws securing the rectifier assembly to the slip ring end bracket and lift off the rectifier assembly. Further dismantling of the rectifier is not required.

Diode Testing:

13. Check the diodes. Connect the test equipment as shown and test each diode in turn, note whether lamp lights, then reverse test lead connections. The lamp should light in one direction only. Renew the rectifier assembly if a faulty diode is diagnosed.
14. Remove the slip ring end bracket bolts and lift off the bracket.

Stator Testing:

15. Connect a 12 volt battery and a 36 watt test lamp to two of the stator connections. Repeat the test replacing one of the two stator connections with the third. If test lamp fails to light in either test, fit a new stator.

Stator Testing:

16. Using a 110 volt a.c. supply and a 15 watt test lamp, test for insulation between any one of the three stator connections and stator laminations. If test lamp lights, fit a new stator.
17. Clean surfaces of slip rings using a solvent moistened cloth.
18. Inspect slip ring surfaces for signs of burning; remove burn marks using very fine sandpaper. On no account should emery cloth or similar abrasives be used, or any attempt made to machine the slip rings.
19. Note the position of the stator output leads in relation to the alternator mounting lugs, and lift the stator from the drive end bracket.

Rotor Testing:

20. Connect an ohmmeter to the slip rings. A reading of 2.6 ohms should be recorded.
21. Using a 110 volt a.c. supply and a 15 watt test lamp, test for insulation between one of the slip rings and one of the rotor poles. If the test lamp lights, fit a new rotor.
22. To separate the drive end bracket and rotor, remove the shaft nut, washers, woodruff key and spacers from the shaft.
23. Remove bearing retaining plate by removing the three screws. Using a press, drive the rotor shaft from the drive end bearing.
24. If necessary, to remove the slip rings or the slip ring end bearing on the rotor shaft, unsolder the outer slip ring connection and gently pry the slip ring off the shaft, repeat the procedure for the inner slip ring connection. Using a suitable extraction tool, withdraw the slip ring bearing from the shaft.

REASSEMBLING
25. Reverse the dismantling procedure, noting the following points.
(a) Use Shell Alvania RA or equivalent, to lubricate bearings.
(b) When refitting slip ring end bearing, ensure it is fitted with open side facing rotor.
(c) Use Fry's H.T.3 solder on slip ring field connections.
(d) When refitting rotor to drive end bracket, support inner track of bearing. Do not use drive end bracket to support bearing when fitting rotor.
(e) Tighten through-bolts evenly.
(f) Fit brushes into housings before fitting brush moulding.
(g) Tighten shaft nut to 27.2-47.5 Nm (20-35 ft lbs).
(h) Refit regulator pack to brush moulding.

26. Reconnect the leads between the regulator, brush box and rectifier.
27. Refit the alternator.