MG MGB User Manual

THE
BRAKING SYSTEM
>
.
M
Place the
main
cup
washer
in position
with
its
concave
face
next to
the
main
cup
and
insert
the
piston,
taking
care
not
to
damage
or
turn
back
the lip of the secondary
cup.
Place
the push-rod
in position,
push the
piston
down the
bore, and with
the
piston
stop
washer
in
the bore
re■t
the
retaining
circlip.
Re■t the dust
cover.
Replacing
Re■t the
master
cylinder
to
the
master
cylinder box
and
secure
it
with bolts
The long bolt
passes
through the
stiffener
plate.
Remove
the dust
excluder and
■t the
pipe
connection
to
the
master
cylinder.
1
Re■t the
clutch pedal lever
to
the push-rod and
secure
it
with the clevis
pin,
washer,
and
a
new
split
pin.
Re■t the
master
cylinder
cover.
Fill the
master
cylinder and
then
prime
and bleed
the
system.
Section
M.6
DISC
BRAKE
UNITS
Description
Each
front
wheel
brake
unit
comprises
a
hub-mounted disc
rotating
with the
wheel
and
a
braking unit
rigidly
attached
to
the
swivel
axle.
The brake unit
consists
of
a
calliper
manufactured
in
two
halves■the mounting
half and the
rim
half—which
are
held
together by
three
bolts. A
cylinder
in
each calliper
half houses
a
self-adjusting
hydraulic
piston,
a
■uid seal,
a
dust
seal,
and
a
seal
retainer.
The
pistons
are
interchangeable
side for
side.
The
friction
pad
assemblies
are
■tted adjacent
to
the
pistons
and
are
retained
in
position
by
a
retainer
spring
and
pin.
Fluid
pressure
generated
in
the
master
cylinder
enters
the
mounting
half of
each calliper
and
passes
through the
internal
■uid
ports
into
the
rim
half.
An
even
pressure
is
therefore
exerted
on
both
hydraulic
pistons,
moving
them
along
the
cylinder
bores
until the
friction
pad
assemblies
contact
the
disc.
In
order
to
compensate
for
wear
of
the
pads the
pistons
move
progressively along
each
cylinder.
The
movement
of the
piston
de■ects the
■uid
seal
in
the
cylinder bore,
and
on
releasing
the
pressure
the
piston
moves
back
into its
original
position
thus
providing
the
required clearance
for
the
friction pads.
Removing
the disc friction
pads
Apply
the hand brake, jack
up
the
car,
and
remove
the
road
wheel.
Depress
the pad
retaining springs
and
remove
the split
pins
and the
retaining springs;
lift the pads
out
of the
calliper.
Before the lining
material has
worn
down
to
a
minimum
permissible thickness
of
in.
(1.59 mm)
the
friction pads
must
be renewed.
Thoroughly clean
the exposed end
of each
piston
and
ensure
that
the.recesses
which
are
provided
in
the
calliper
to
receive
the friction pads
are
free
from
rust
and
grit.
Before ■tting
new
friction
pads the calliper
pistons
which
will be
at
their
maximum
adjustment,
must
be returned
to
the base of the bores,
using
a
suitable clamp.
MGB. Issue
3.
15676
NOTE—The level of the ■uid
in
the
master
cylinder supply
tank will
rise
during this
operation
and
it
may
be
necessary
to
siphon off
any
surplus
fluid
to prevent
it
from
over■owing.
Check that the
portion
that
has been machined
away
from
the face of
each
piston is
correctly
positioned
at
the
inner
end of the calliper
(see
Fig.
M.6).
Insert the
friction
pads
(which
are
interchangeable
side for
side),
replace
the
retaining springs,
and
■t the
split
pins.
Ensure that the
pad
assemblies
are
free
to
move
easily
in
the
calliper
recesses.
Remove
any
high-spots from the
pad
pressure
plate by
■ling
carefully.
Pump the brake pedal several
times
to
readjust the
pistons
and
top
up
the ■uid
supply
reservoir.
Removing
a
calliper
unit
Apply the hand brake,
jack
up
the
car,
and
remove
the road
wheel. Withdraw
the
brake
friction pads.
Attach
a
bleeder tube
to
the
bleed
screw
and drain the ■uid
by
pumping
the brake pedal.
Disconnect
the
■exible
hose
on
the
mounting
half of the calliper
(see
Section
M4)
and
plug the end of the hose
to
prevent
the
entry
of foreign
matter.
Press back the
ears
of
the locking washer,
unscrew
the
two
bolts
securing
the calliper
to
the swivel axle and withdraw
the calliper complete.
Replacing
Reverse
the above
instructions.
Tighten the calliper
securing
bolts
to
the
torque
spanner
reading of
40
to
45
1b. ft.
(5.6
to
6.2
kg.
m.).
Finally
bleed the
system
as
described
in
Section M.4.
Fig. M.4
Friction
pad retaining pins and bleed
screw
location
M.5

MG MGB Specifications

General

Brand	MG
Model	MGB
Category	Automobile
Language	English