MG MGB User Manual

THE OVERDRIVE
Fa
adaptor and the
two
screws
from the
rear
support
bracket.
Take
care
not to
damage the
joint
washer.
The
unit is
split
at
the gearbox adaptor,
which
is
attached
to
the
main
casing
by
eight 11:
in.
(6.35 mm.)
diameter
studs,
one
of which
is
extra
long.
After
removing
the eight
nuts
the
unit
can
then be drawn
off the third
motion
shaft.
Remove the
operating
valve
plug
(see
Section
Fa.8).
This
will allow
air
to enter
the
cylinders
of
the
operating pistons
and
thus facilitate
their removal.
Release the lock
washers
securing
the
nuts
on
the
two
operating
bridge
pieces
and
remove
the
nuts,
lock
washers, and bridge
pieces.
Withdraw the
operating pistons
by
gripping
their
spigots
with
pliers.
As
the adaptor
is
separated from the
unit
the grub
screw
securing
the
pump
body
can
be withdrawn
and the body
pulled
from the
casing
after
removing
the
non-return
valve
(see
Section
F35).
The
main
and
rear
casings
are
secured by eight %
in.
(6.35
mm.)
diameter
studs:
unscrew
the
nuts
a
little
at
a
time,
gradually releasing
the four clutch
springs.
Remove
the
main casing
complete with
brake
ring.
Take
the fourclutch
springs
off their
guide bolts
on
the
thrust plate
and
remove
the clutch
assembly complete
with
sun
wheel.
The brake
ring is
spigoted
into
each
casing
and will
come
away
with the
main casing.
A
few light
taps
with
a
mallet
around
its
■ange will
release
the
ring.
Remove the
sun
wheel from
the
cone
clutch
boss
by
withdrawing
the
snap
ring in
the forWard
end
of
the
sun
wheel
hub.
Remove
the
large circlip
and withdraw the
thrust
bearing and
housing
complete.
Lift
out
the
planet
carrier
assembly from
the annulus.
If
it
is
necessary
to
remove
the uni-directional
roller clutch, ■rst
remove
the
circlip and brass
retaining
washer which
are
in
front of the
clutch.
Place
Service tool 18G
178
centrally
over
the clutch
and lift
the
inner member into
it.
This
will
ensure
that
the rollers
do
not
fall
out
of the
inner member.
Remove the thrust
washer.
DO
NOT
remove
the
outer
bearing
ring,
as
it is
expanded
into
the
annulus.
A
caged
needle-roller bearing
is
■tted
in
the annulus
centre
spigot.
If
it
is
necessary
to
remove
this
use an
extractor.
To
remove
the
annulus from the
rear
casing
withdraw the
speedometer
pinion
and
bush
located by
one
dowel
screw,
take
off the
coupling
■ange
at
the
rear
of the
unit, and
drive
out
the annulus from
the
back.
The
front
bearing will
come away on
the
shaft, leaving the
rear
bearing
in
the
casing.
Inspection
Each
part
should be thoroughly cleaned
and
inspected
to
determine which
parts
need
renewing.
It
is important
to
appreciate
the difference
between
parts
which
are worn
suf■ciently
to
affect
operation
of the
unit and those which.
are
merely ‘worn
in’.
1. Inspect
the
main casing
for
cracks,
damage,
etc.
Examine the
bores
of
the
operating
cylinders for
scores or
wear.
Check for leaks
at
the
plugged ends of
MGB. Issue4.
65891
10.
the oil
passages.
Inspect the
support
bush
in
the
centre
bore for
wear
or
damage.
Examine the clutch
sliding
member
assembly.
Ensure
that the clutch
linings
are
not
burned
or
worn.
Inspect
the clutch
spring
locating
bolts
and bridge
pieces and
see
that they
are
not
distorted. Ensure that
the ball
bearing
is in
good
condition
and
rotates
freely.
See
that the
sliding
member slides easily
on
the splines of
the
sun
wheel.
Check
the
springs
for
distortion
and
collapse
(see
‘GENERAL
DATA’).
Inspect
the teeth
of the
gear
train
for
damage.
If
the
gears
are
damaged
or
the
needle rollers
worn, renew
the
planet
carrier assembly. The
sun
wheel
bush‘
is
bored
to
the pitch
line
of
the teeth,
and if
worn,
the
gear
will
have
to
be renewed.
Examine the
uni-directional clutch thrust
washer.
See
that the
rollers of the
uni-directional clutch
are
not
chipped
and that the
outer
ring is
tight
in
the
annulus. Ensure
that the
spring
is
free from
distortion.
Inspect
the
output
shaft
ball
bearings
and
see
that
there
is
no
roughness
when they
are
rotated
slowly.
Ensure that there
are
no
nicks
or
burrs
on
the
third
motion
shaft
splines
and
that
the
oil
holes
are open
and clean.
Inspect
the
oil
pump
for
wear on
the
pump
plunger
and
roller
pin.
Ensure that
the plunger
spring is
not
distorted (see
‘GENERAL
DATA”).
Inspect the valve
seat
and ball
and make
sure
that they
are
free from
nicks and scratches.
Check the
operating
valve for
distortion
and damage
and
see
that
it
slides
easily
in its bore.
Inspect the
relief
valve body,
‘0’
ring,
and ball,
etc.
Reassembling
the
unit
Assemble
the
unit
after
all
the
parts
have
been
thoroughly
cleaned
and checked
to
ensure
that
none
is
damaged
or
worn.
,..u'
.
..
.
w'o'o'o‘o'o'o'I'tf':
u.
'
."Hv.
-~vmu'o‘mm,.u
‘
.3339:lf'f.%'o‘M°“-‘“‘
Fig. Fa.8
Use
Service
tool 18G
178 when
removing
or
replacing
the
uni-directional
clutch inner
member.
Fa.9

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English