MG MGB User Manual

Fa
THE
OVERDRIVE
Fit
the annulus
assembly
with the speedometer
drive
gear,
spacing
tube,
and
shim
which ■t
on
the shaft between
the
front
and
rear
ball
bearings in
the
rear
casing.
If
a
new
bearing is
■tted
it
becomes
necessary
to
assess
the
thickness
of shim
required.
To do
this
replace the
annulus
in
the
rear
casing
with the
speedometer
drive
gear
and
distance
tube
in
position,
and
with
a
depth
gauge
measure
the distance
between
the
rear
ball bearing
seating
and the
distance
tube.
To
this
■gure add .005
to
.010 in.
(.13
to
.25
mm.): this
will
give
the
actual
shimming
required.
The
shims
are
available
in
the
following thicknesses
for
selective
assembly,
which
should allow
an
end-■oat
of
.005
to
.010
in.
(.13
to
.25
mm.)
on
the
output
shaft
and
no
preloading
of the bearings:
.090
in.i.0005 in.
(2.28 mm.i.01
mm.)
.095
in.:t.0005 in.
(2.41 mm.i.01
mm.)
.100 in:
0005
in.
(2.54 mm.i.01
mm.)
.105
in.i.0005
in.
(2.67
mm.i.01
mm.)
Replace
the coupling
■ange and
tighten
the
nut to
a
torque
reading
of 100
to
130
lb.
ft.
(13.83
to
17.97
kg.
m.),
holding
the
■ange
against
rotation
with the aid
of
a
wrench
(Service
tool
18G34A).
Fit
the
speedometer
drive
bush and pinion
and
lock
in
position
with the
dowel
screw.
Replace
the
thrust
washer
and
uni-directional
clutch,
using
Service
tool 18G178
to
enter
the rollers
in
the
outer
ring.
Ensure
that the
spring
is
■tted
correctly
so
that the
cage
urges
the rollers
up
the
ramp on
the
inner
member.
Fit the brass retaining
washer and
locate
it
in
position
with
the circlip.
To
ensure
that
the second
set
of teeth
on
each planet
wheel
will
mesh
with the
annulus teeth
turn
each planet
wheel
until
its
etched line
coincides
with
an
etched
line
on
the
carrier.
insert
the
sun
wheel
to
hold the planet
wheel
in
these relative
positions.
Fit the
assembly
to
the
annulus
and
withdraw the
sun
wheel.
As
long
as
the planet
carrier
remains
in
the
annulus the
sun
wheel
can
be
removed
and
reinserted
at
any
time.
Should
the planet carrier
be
removed
from the
annulus,
the
whole
lining-up
procedure
must
be
repeated.
Pass the
sun
wheel
into
the
cone
clutch member
and
■t the
small
circlip
at
the
forward end
of the
sun
wheel.
Press the
thrust bearing into its
housing,
■t the four
bolts
to
the
thrust
bearing
housing,
and
then ■t the
assembly
onto
the
forward end
of the
cone
clutch hub,
securing
in
place with
the large
circlip.
Fit
the
clutch assembly
to
the annulus,
engaging
the
sun
and planet
wheels.
Place the
thrust
plate
and
springs
on
the
bolts
Assemble
the
brake
ring
to
the
main
casing
(large end
of
taper
towards
the
rear
casing) with
a
jointing
compound.
Position
the
clutch
bolts
through
the
holes
in
the
main
casing.
Start
the
nuts
on
the
casing
studs
and
gradually
tighten
to
secure
the
two
casings
together.
Ensure that
the
clutch
spring
bolts do
not
bind in
their holes
and that
the
casings
go
together easily.
Fit the
two
operating pistons,
carefully
easing
their rubber
,
sealing
rings into
the cylinder bores
(the
centre
spigots
of
r
Fa.10
the
pistons
face towards
the front
of
the
unit).
Fit the
two
bridge
pieces,
lock washers, and
nuts.
'
If the
pump
body has been
removed,
insert
its
small end
into
the
casing
in
the middle hole
at
the bottom
of the
casing, ensuring
that
the oil inlet
faces
to
the
rear.
Gently
tap
into
position
until the
groove
lines
up
with the grub
screw
hole
at
the bottom
of the
casing
front face. Fit
the
grub
screw
and
tighten.
Re■t the
non-return
valve
(see
Section
Fa.5).
Insert
the
pump
plunger and
spring
from
inside the
casing.
Replace
the
operating
valve
plug.
Support
the
unit
upright and
insert
a
dummy
shaft
or
a
spare
third
motion
shaft
so
that the planet
carrier
and
uni-directional
clutch line
up
with each other;
a
long,
thin
screwdriver
should be used
to
line by
eye
the
splines
(turn
anti-clockwise
only)
in
the
planet
carrier
and
the
clutch
before
inserting
the dummy
shaft. Gently
turn
the
dummy
shaft
to
assist in
feeling
it
into
the splines, making
sure
that
it
goes
fully
home.
Make
sure
that the lowest
part
of the
oil
pump
cam
will
contact
the
pump
plunger
and that
the third
motion
shaft
clip
is
seated
in its
groove;
then
with
top
gear
engaged,
carefully thread
the third
motion
shaft
into
the
centre
bushing
in
the
unit.
Gently
turn
the ■rst
motion
shaft
to
and fro
to
assist in
engaging
the
splines
of
the
planet
carrier.
As the
adaptor
and overdrive
come
together watch
carefully
to
see
that
the oil
pump
engages
the
cam
properly.
NOTE;
The
gearbox third motion
shaft should
enter
the
overdrive easily,
provided
that the lining-up
procedure
previously
described
is
carried
out
and the
unit is
not
disturbed.
If
any
difficulty is
experienced
it is
probable that
one
of the
components
has been
misaligned,
and
the
gearbox
should be removed
and the
overdrive
realigned
with the dummy
shaft.
Replace
the
remote
control
tower,
ensuring
that the change
speed lever
engages
the selector.
Fig.
Fa.9
Before assembling
the planet carrier
to
the
sun
wheel
rotate
the
planet wheels until the
etched line
on
the planet
wheel
lines
up
with the etched line
on
the planet carrier
MGB. Issue
2.
54980

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English