MG MGB User Manual

N
THE
ELECTRICAL
SYSTEM
Dismantling the
motor
Withdraw the four
screws
securing
the
gearbox
cover
and
remove
the
cover.
Withdraw
the
connectors
and through-bolts
at
the
commutator
end bracket.
Remove the
commutator
end bracket
clear
of the yoke.
The brush
gear
can
be
removed by lifting
it
clear of
the
commutator
and
withdrawing
it
as
a
unit.
Care
should
be
taken
at
this
point
to note
the
particular side
occupied by
each brush
so
that
each
may
be
replaced
in its original
setting
on
the
commutator.
Access
to
the
armature
and ■eld
coils
can
be
gained by
withdrawing
the
yoke.
If
it is
necessary
to
remove
the field
coil,
unscrew
the
two
screws
securing
the
pole-piece
to
the
yoke. These
screws
should
be
marked
so
that they
can
be
returned
to
their
original holes.
Press
out
the pole-piece
complete
with
field
coil,
marking
the
pole-piece
so
that
it
can
be
replaced
in
its
correct
position
inside the
yoke.
The
pole-piece
can
now
be
pressed
out
of
the field
coil.
Pieces of
carbon short-circuiting
adjacent
segments
of
the
commutator
will
also
cause
excessive
current
consumption.
The
resistance between
adjacent
commutator
segments
should
be
.34
to
.41 ohm.
Cleaning
the
commutator
and
brush
gear
removes
this fault.
When
dismantling,
check
the
internal
wiring
of
the
mo
tor
for
evidence of
short-circuiting
due
to
chafed
or
charred
insulation.
Slip
a new
piece
of
sleeving
over
any
charred
connections,
and
arrange
them
so
that they
do
not
rub
against
sharp
edges.
While
the
motor
is
dismantled
check
the
value of
the field
resistance.
If
it is
found
to
be lower
than
12.8
to
14
ohms
a
short
circuit
in
the
windings
is
indicated
and
a new
field
coil
must
be ■tted.
Other
evidence
of
a
short
circuit will be
given
by
charred
leads
from the field
coil.
Disrmntling the
gearbox
unit
Remove the
circlip and
washer from
the
cross-head
connecting
link
pin
and lift off
the
cross-head
and cable
rack assembly.
Then
remove
the
circlip
and washer
from
the
■nal
gear
shaft located
underneath
the
gearbox
unit.
Remove
any
burr
from the
circlip
groove
before lifting
out
the ■nal
gear.
The
armature
and
worm
drive
can
now
be
withdrawn
from
the
gearbox.
A11
gear
teeth
should be
examined for
signs
of
damage
or
wear
and, if
necessary,
new gears
■tted.
Reassembling
Reassembly
is
a
reversal of the
above
procedures.
When
reassembling,
the
following
components
should
be
lubricated,
using
the
lubricants
recommended.
ARMATURE
BEARINGS
These
should
be'lubricated
with
S.A.E.
20
engine
oil,
the
self-aligning
bearing
being
immersed
in
this
for
24
hours
before
assembly.
N.18
v
,.
ARMATURE
SHAFT (COMMUTATOR
END)
Apply
S.A.E.
20
engine
oil.
FELT
LUBRICATOR
IN GEARBOX
Apply
S.A.E.
20
engine oil.
WORM
WHEEL
BEARINGS,
CROSS-HEAD,
GUIDE
CHANNEL,
CONNECTING
ROD,
CRANKPIN,
WORM
AND
FINAL
GEAR
SHAFT
Grease
liberally.
,
CABLE
RACK
AND
WHEELBOXES
Grease
liberally.
Testing
Switch
on
the
ignition
and the
wiper
control. The
two
wiper
areas
should
be
approximately
symmetrical
on
the
windshield.
Fig.
N.14
Light
unit
retaining
screws
1.
Removable
screw.
2.
Combined
adjusting/
retaining
screw.
3.
Captive
retaining
screw.
4.
Beam-setting
adjusting
screws.
MGB.
Issue5.
25729

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English