9 Alternator charging system -
testing
2
Note: Refer to the warnings given in “Safety
first!” and in Section 1 of this Chapter before
starting work.
1 If the ignition warning light fails to illuminate
when the ignition is switched on, first check
the alternator wiring connections for security.
If satisfactory, check that the warning light
bulb has not blown, and that the bulbholder is
secure in its location in the instrument panel.
If the light still fails to illuminate, check the
continuity of the warning light feed wire from
the alternator to the bulbholder. If all is
satisfactory, the alternator is at fault and
should be renewed or taken to an auto-
electrician for testing and repair.
2 If the ignition warning light illuminates when
the engine is running, stop the engine and
check that the fan belt is correctly tensioned
(see Chapter 1) and that the alternator
connections are secure. If all is so far
satisfactory, check the alternator brushes as
described in Section 11. If the fault persists,
the alternator should be renewed, or taken to
an auto-electrician for testing and repair.
3 If the alternator output is suspect even
though the warning light functions correctly,
the regulated voltage may be checked as
follows.
4 Connect a voltmeter across the battery
terminals and start the engine.
5 Increase the engine speed until the
voltmeter reading remains steady; the reading
should be approximately 12 to 13 volts, and
no more than 14 volts.
6 Switch on as many electrical accessories
(eg, the headlights, heated rear window and
heater blower) as possible, and check that the
alternator maintains the regulated voltage at
around 13 to 14 volts.
7 If the regulated voltage is not as stated, the
fault may be due to worn brushes, weak brush
springs, a faulty voltage regulator, a faulty
diode, a severed phase winding or worn or
damaged slip rings. The brushes may be
checked as described in Section 11, but if the
fault persists, the alternator should be
renewed or taken to an auto-electrician for
testing and repair.
10 Alternator - removal and
refitting
1
Removal
Note: If working on a pre-1990 car fitted with
exhaust emission control equipment, it will be
necessary to remove the air pump and
drivebelt as described in Chapter 4C to
provide access to the alternator.
1 On models fitted with an ignition shield over
the front of the engine release the three
retaining lugs and lift off the shield.
2 Release the spring clip and disconnect the
wiring connector from the rear of the
alternator.
3 Slacken the alternator adjusting arm nut
and the bolt securing the adjusting arm to the
alternator.
4 Slacken the two upper mounting nuts and
bolts, move the alternator toward the engine
and slip the fan belt off the pulley.
5 Remove the two upper mounting nuts and
bolts and the bolt securing the adjusting arm
to the alternator. Lift the alternator off the
engine.
Refitting
6 Refitting is the reverse sequence to
removal. Ensure that the fan belt is correctly
tensioned as described in Chapter 1 before
finally tightening the mounting and adjustment
arm bolts.
11 Alternator brushes - renewal
3
11AC alternator
1 Remove the alternator from the car as
described in Section 10.
2 To remove the brushes, undo and remove
the nut and spring washer, the large Lucar
terminal and the plastic strip from the output
terminal.
3 Undo and remove the two securing screws
and withdraw the brush box. Note that there
are two small washers between the brush box
and end bracket.
4 Close up the retaining tongue at the root of
each terminal blade and withdraw the brush,
spring and terminal assemblies from the brush
box.
5 With the brushes removed, measure their
length, and renew them if worn to less than
the minimum specified length.
6 Check that the brushes slide smoothly in
their holders. Any sticking tendency may first
be rectified by wiping with methylated spirit
and a clean cloth, or if this fails, by carefully
polishing with a very fine file where any
binding marks may appear.
7 Refitting the brushes is the reverse
sequence to removal. When refitting the
terminal blades to the brush box bend the
retaining tongue, at the root of each blade, out
slightly to retain the blade in position.
16ACR alternator
8 Remove the alternator from the car as
described in Section 10.
9 Undo and remove the two retaining screws
and lift off the moulded end cover.
10 Detach the cable from the terminal blade
on the outer of the three rectifier plates. Also
detach the cable from the blade between the
middle and inner of the three rectifier plates.
11 Undo and remove the four screws
securing the brush assemblies to the brush
holder.
12 Undo and remove the screw securing the
surge protection diode cable to the brush
holder.
13 Finally undo and remove the three bolts
and lift off the brush holder and regulator
assembly. Note that there is a small leaf
spring fitted at the side of the inner brush.
14 Check the condition of the brushes as
described in paragraphs 5 and 6.
15 Refitting the brushes is the reverse
sequence to removal.
A115 alternator
16 Remove the alternator as described in
Section 10.
17 Disconnect and remove the interference
suppression capacitor from the end cover.
18 Undo the screws or nuts which secure the
end cover, and remove the cover.
19 Unscrew the surge protection diode
securing screw. Either move the diode
carefully out of the way, or disconnect it from
the rectifier board and remove it.
20 Make a careful note of the regulator lead
colours and fitting arrangements, then
disconnect the regulator leads from the
rectifier board and remove it.
21 Remove the regulator screw and withdraw
the regulator. Note that the regulator securing
screw also holds one of the brush mounting
plates in position.
22 Remove the two securing screws, and
withdraw the brushbox. Extract the free
brush, then undo the securing screw to
release the other brush. Remove the sealing
pad.
23 Renew the brushes if they are at, or
approaching, the minimum specified length.
Check the brush spring pressure with the
brush ends flush with the end of the
brushbox; renew the springs if they have
become weak.
24 Refitting the brushes is the reverse
sequence to removal.
A127 alternator
25 Remove the alternator as described in
Section 10.
26 Undo the three small screws securing the
regulator and brushbox assembly to the rear
of the alternator.
27 Tip the assembly upwards at the edge,
and withdraw it from its location. Disconnect
the rectifier wiring connection, and remove
the regulator and brushbox.
28 Measure the brush length, and renew the
regulator and brushbox assembly if the
brushes are worn below the figure given in the
Specifications.
29 Refitting the brushes is the reverse
sequence to removal.
5A•6 Starting and charging systems
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