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PART 2-2
BRAKE SYSTEM
2-9
sembly
pivots
on a
stationary
pedal
mount
(Fig.
5).
A
spring-loaded
pawl and a
release
lever
are
assem
bled
to the
pedal.
A
ratchet
is
as
sembled
to
the
stationary
mount.
The
pawl
contacts
the
ratchet
at
such an angle
that
it
will slide over
the
ratchet
teeth
as
the
pedal
is
depressed; however,
when
the
ap
plying
motion
stops
and
the
pedal
starts
to
release,
the
pawl
engages
the
ratchet
and
thus
locks
the
brakes
in
the
applied
position.
Since
the
release
lever
pivots against
the pawl,
a
slight
movement
of
the
release
lever
will
disengage
the
pawl
from
the
ratchet
allowing
the
brakes
to
release.
The
release
lever
is
actuated
by
a
manual release
handle
which
is
connected
to
the
lever
through
a
slot
and
rivet
pin
(Fig.
5).
The
vacuum
power
unit
with
mounting bracket is
riveted
to
the
control
assembly.
The
vacuum
ac
tuated
piston within
the
unit
is
con
nected
by
a
link
to the
upper
end
of
the
release
handle
which actuates
the
release
lever
to
move
the
pawl
out of
engagement with
the
ratchet
(Fig. 5).
The lower
end
of
the
re
lease handle
extends out
for
alternate
manual
release
in
the
event
of
vacuum
power
failure
or
for op
tional
manual release
at
any
time.
Hoses
connect
the
power unit and
the
engine
manifold
to
a
vacuum
release
valve
in
the
transmission
neutral
safety
switch
(Figs.
5
and
6).
Moving
the
transmission
selector
lever into
any drive
position
with
the
engine
running
will
open
the
release valve
to
connect engine mani
fold
vacuum
to
one
side
of
the
actuating
piston
in
the
power
unit.
The
pressure
differential
thus
created
will cause
the
piston and
link
to
pull
TO
VACUUM
POWER UNIT
CONNECTS
WITH
VENTILATION
SYSTEM
NEUTRAL
SAFETY
SWITCH
(VACUUM
RELEASE
VALVE)
COWL
X
TO
ENGINE
MANIFOLD
VACUUM
H1313-A
FIG. 6-Vacuum
Connections
for
Automatic
Parking
Brake Release
the
manual release
handle
which,
in
turn,
actuates
the
release
lever.
IN-CAR ADJUSTMENTS AND REPAIRS
BRAKE
SHOE
ADJUSTMENTS
The
car should
be
raised with
the
wheels
off
the
floor. If the
car
is
raised
on
a
frame-contact
hoist,
disconnect
the
parking
brake
cables
to
prevent
the
rear
brakes
from
being
partially
applied
due
to
rear
axle
and
spring
sag
on
the
hoist.
The hydraulic
service
brakes
are
self-adjusting
and
require
a
manual
adjustment
only
after
the
brake
shoes
have
been
relined,
replaced,
or
when
the
length
of
the
adjusting
screw
has been
changed
while
per
forming
some
other
service
opera
tion.
The
brake
drums
should
be
at
normal
room
temperature
when
ad
justing
the
brake
shoes.
If
the
shoes
are
adjusted
when
the
drums
are
hot
and
expanded,
the
shoes
may
drag
when
the
drums
are
cool
and
contracted.
1.
After
the
shoes
have been in
stalled
or
the
adjusting
screw
has
been
turned,
install
the
drum.
Be
sure
that
all
excess
grease,
oil,
and
other
foreign
material
are wiped
off
the
carrier plate
and
drum.
Before
installing
the
brake drum
on
the
front
wheel
spindle,
wipe
the
spindle
completely free
of grease.
Install
the
drum carefully
so
that
the
grease
seal
retainers
within
the
hub
will
not
be
damaged.
2.
Remove
the
adjusting
hole
cover
from
the
carrier
plate
and,
from
the
carrier plate
side, turn the
adjusting
screw
upward
to
expand
the
shoes
(Fig. 7). Expand
the
shoes
until
a
drag
is felt
when
the
drum
is
rotated.
3. Remove
the
drum.
Mark
the
tooth
on
the
star
wheel
where
the
lever
contacts
the
adjusting
screw.
While
holding
the
adjusting
lever
out of engagement with
the
adjusting
screw,
back
off
the
adjusting
screw
Va
of
a
turn
with
the
fingers. If
finger
movement
will
not
turn the
screw,
free it
up;
otherwise,
the
self-
adjusting lever
will
not
turn
the
screw.
Lubricate
the
screw
with
a
thin
uniform
coating
of
high-tem
perature grease
(see Specifications).
Any
other adjustment procedure
may
cause
damage
to
the
adjust
ing
screw
with
consequent self ad
juster
problems.
4.
Apply
a small
quantity
of
high-
temperature
grease
to
the
points
where
the
shoes
contact
the
carrier
plate,
being
careful
not
to
get
the
lubricant
on
the
linings. Install
the
drum.
On
a
front
wheel,
install
the
wheel
outer
bearing,
washer,
and
adjusting
nut,
then
adjust
the
wheel
bearings
as
outlined
in
Part
3-4,
Section 2.
On
a rear
wheel,
install
the three
Tinnerman
nuts
and
tighten
se
curely.
5. Install
the
wheel
on
the
drum
and
tighten
the
mounting
nuts
to
specification.
6.
Install
the
adjusting hole
cover
on
the
brake
carrier
plate.
7.
When adjusting
the
rear
brake
shoes,
check
the
parking
brake
cables
for
proper
adjustment.
Make
sure
that
the
equalizer
lever
oper
ates
freely.
8. After
the
brake
shoes
have
been
properly
adjusted,
check
the
operation of
the
brakes.
FRONT BRAKE DRUM
REMOVAL
1. Raise
the
car
until
the
wheel
and
tire
clear
the
floor. Remove
the
Broke Shoe
Adjusting
Tool
FIG.
/-Expanding
Brake Shoes
H1153-A
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