DATSUN PICK-UP 1977 Service Manual

DISASSEMBLY

AND

ASSEMBLY

1

00
11I

1

Reservoir

cap

2
Oil
mter

3
Oil

reservoir

4

Packing

5
Valve

cap
Brake

System

00

oC
1

O

b
0
1

r
r

L

BA927

6

Secondary
piston

stopper

7

Bleeder
screw

8

Secondary
return

spring

9

Secondary
piston

10

Primary
return

spring
11

Primary
piston

12
Piston

stopper

13
Piston

stopper
ring

1
Remove
reservoir

cap
and
filter

and
drain
out
brake
fluid

2

Pry
off

stopper
ring
using
a

screwdriver

3
Remove

stopper
screw
and

take

out

stopper
primary
piston
assembly

spring
and

secondary
piston

assembly

in
the

order
shown

Note
Discard

piston
cup
if
it
is
re

moved
from

piston
sembly
and

use
a
new

one

4

Unscrew

plugs
to

gain
access
to

check

valve
for

disassembling

Note
Never
detach
reservoir
tank
U

it
is
removed
for

any
reason
dis

canI
it

and
install
a
new
one

S
Assemble
master

cylinder
in

the

reverse

sequence
of

disassembly
pay

ing
particular
attention
to
the

follow

ing
notes
Fig
BR
10
Master

cylinder

Tightening
torque

Valve

cap

T
okico

8

t09

kg
m

S8
to
6S
ft
Ib

Nabco

2
5
to
3
S

kg
m

18
to
2S

ft
Ib

Bleeder

0
7

to
0

9

kg
m

S
to

7
ft
lb

Notes

a

Replace
gaskets
and

packings
with

new
ones

b

Apply
brake
fluid
or
rubber

grease

to

sliding
contact
surfaces
of

parts

to
facilitate

assembly
of
master

cylinder

c
The
blllke
master

cylinder
is
avail

able
in
both
NABCO
make
and

TOKlCO
make
There
is
no
inter

changeability
of

repair
kits
or
com

ponent
parts
between
NABCO
and

TOKlCO
JIIlkes
When

replacing

the

repair
kit

or

component

parts

BR
6
ascertain
the
brand
of
the
brake

master

cylinder
body
Be

sure
to

use

parts
of
the

same
make
as
the

former
ones

INSPECTION

Thoroughly
clean
all

parts
in

a

suitable
solvent
and
check
for
WOol
or

damaged
parts
Replace
any

part
that

is

faulty

Note
Do

not
clean
robber

parts
with

minerai
oil
since
this
will
be
the

sure

way
of

deteriolllting
parts
Use

brake
fluid
or
alcohoL
When

alco

hol
is
used
for

leaning
these

parts

do
not

immerse
them

in
it

longer

than
30

seconds
After

parts
are

cIeaned

dry
with

compressed
air

I
Check

cylinder
and

position
for

evidence
of
abnonnaI

wear
or

damage

Replace
if
found

faulty

2

Check

piston
to

cylinder
clear

ance
If
it
is

more
than

O
IS

mm

0
OOS9
in

replace
either

piston
or

cylinder

Master

cylinder
inner
diameter

19
0S
mm
Yoin

3
Check
for
weakened

fatigued
or

damaged
springs
and

replace
if
neces

sary

4
When
master

cylioder
is

disassem

bled
be
sure
to

discard

cups
and

valves

Replace

any
other

part
which

shows

evidence
of
deformation
wear

or

damage

S

Replace
damaged
oil
reservoirs

and

caps

INSTALLATION

Install
master

cylinder
in
the

re

verse

sequence
of
removal

Bleed
air

out
of
master

cylinder
by

loosening
bleeder
screw
after
it
is

installed
in

its

original
position

Tightening
torque

Brake
master

cylinder

attaching

nut

0
8
to
1
1

kg
m

6
to
8
ft
Ib

Brake
tube
connector

I
S
to
1
8

kg
m

II

to
13
ft
Ib

BRAKE

LINE
Brake

System

Detail
A

Detail
B

Detail
C
Detail
D

Detail
E

Detail
of
Detail

G

Detail
R

Detail
1

BR
7
Detail

K

Detail
L

BA767

Fig
BR
ll
Brake
line

REMOVAL

1

Removing
flare

nuts
on

both
ends

and

clips
effects
the

removal
of

brake

tube
and
brake
hose

2

Rear
brake
hose
can
be

removed

by
disconnecting
the
tube
and
then

turning
round
the
hose

Note
When

removing
brake
tubes
and

hoses

use
Flare
Nut

Torque

Wrench
GG943IOOOO

Never
use

an

OpeD
end

or
an

adjust

able
wrench

INSPECTION

1
Examine

all
hoses
for
swell

rubbing
marks
or
ozone
cracking

re

placing
those

found
with

any
of
above

badly
beyond
use
Also

inspect
end

fittings
and
be
sure
that
no
fluid
leak

through
staked
end

has
taken

place

replace
if

necessary
Hose

with

badly

rusted

fitting
should

also
be

replaced

with
a
new
one

2

Clean
all
tubes

to
remove
dust

and

dirt
with

isopropyl
alcohol

check

ing
for

collapse
wear

cracking
swell

or

rusting
Replace
if
foun
d

with

any

of
wove
Use
care
not
to

damage

brake
tubes

while

operation

Check
if
tubes

are

clamped
secure

ly

Mter
all

brake
lines

have
been

installed

retighten
aU
connections
if

necessary
to

assist
in

obtaining
correct

torque
In

retightening
at
front
wheel

cylinder
first
remove
hose

clamp
and

loosen
flare
nut
on

opposite
side
to

avoid

twisting
hose

Hold

pedal
as
far
downward
as

possible
80

kg
176
lb
or
more

examining
evidence
as
to
whether
fluid

is

leaking
through
brake

lines
or

con

nections

Leakage
in

any
manner
can

not
be

permitted
here
In

case
fluid

leaks

tightening
to

specified
torque

tighten
additionally
up
to
2
5

kg
m

J
8
ft
lb
Under

no
circumstances

should
not

be

tightened
over
2
5

kg
m

18
ft
Ib

torque
since
this

elongates

end

fitting
making
it

impossible
to

reuse
brake
tube

Under
no
circumstances
should
rear

brake
hose
and
3

way
connector
be

retightened
over

specified
torques
In
Brake

System

stead

replace

copper
washer
with
a

new
one

after

checking
for

sign
of

damage
on

seating
surface
Never
reuse

an
old

copper
washer

INSTALLATION

Brake
hose

Front
brake

hose

In

installing
brake
hose
first

jack

up
vehicle

to
take
off
the

weight
of

vehicle
from

wheels
so
that

suspension

is
in
rebound

Steering
wheel
should

also
be

kept
in

straight
ahead

position

To
connect
brake

line
first

connect

brake

hose
to
wheel

cylinder
with
the

specified
torque

Tightening
torque

1
7
to
2

0

kg
m

12
to

14
ft
Ib

Then
secure

brake
hose
to
the

bracket
with
lock

plate
so
as
not
to

twist
or

abnormally
bend
the
hose

Note

After

connecting
brake
hose

at

both
eiuIs

pay
keen
attention
not

to
twist
the
hose
when
additional

tightening
is

required

Fig
BR

12
Front
brake

hose

Rear

brake
hose

First
secure
rear
brake
hose
to

3

way
connector
on
rear
axle
case
to

the

specifications
Mter

connecting

hose
do
not

tighten
it

at
3

way

connector

additionally
since
this

oper

ation

causes
hose
to
be
twisted

Tightening

torque

I
7

to
2
0

kg
m

12
to
14
ft
Ib

BR
8
Fig
BR
13
Rear
brake
ho
e

After
brake
hose
has
been
installed

check

to
be

sure
that
there
is

enough

clearance
between
hose
and

adjacent

parts
to
avoid
contact
with
other
ones

The
check
should
be
carried
out
while

moving
wheel

up
and
down

through
its

full

stroke
and

rotating
steering
wheel

between
two
extreme
lock

positions

The
wow
clearance
must
be
as

follows

Hose

to

rotating
or

mOving
parts

such
as
tire
and

rim

40
mm
1
57
in

and
more

Hose
to

stationary

part

2S

mm
0

98
in
and
more

In

case
that
the

above
clearance

cannot
be
obtained
it

may
be
caused

by
the
hose

twisted

Accordingly

carry
out
the
correction
with
hose

connection

again
following
the
above

instructions

Brake
tube

In

installing
a
brake
tube
use
care

to
locate
its

end

squarely
on

mating

seat

noting
the
fact
that
nut
can
be

turned

freely
by
a

light
finger
twist

Then

tighten
to
correct

torque
with
a

Brake

Pipe
Torque
Wrench

GG943
10000

Tightening
torque
Flare
nut

1
5
to
1

8

kg
m

11
to

13
ft
Ib

In
addition
care
should
also
be

exercised
to
avoid

damaging
or
col

lapsing
brake
tube

during
operation

Be
sure
to
make

enough
clearance

between
all
tubes
and
other

adjacent

parts
to
avoid
contact

In

installing
tube

through
hood

ledge

grommet
be
sure
to

position
it

at
the

center
of

grommet

After

connecting
brake
tube
be

sure
to

check
the
clearance
to

prevent

from

damage
The
clearance
at

the

following
portions
must
be

specified

distance
or

more

Tube
to

body
panel
and

frame

Over
5

mm
0
20
in

Tube

to
edge
of
each

panel

Over
10
mm
0
39

in

Tube
to
tube

Loop
pitch

OVer
5
mm
0
20
in

Between
front
tube
and

rear
tube

Over
9

mOl
0
35

in

Tube
to

moving
parts

Over
10
mm
0
39
in

Loop
tube
to

hood

ledge

panel

Over
10

mm
0
39
in

Notes

a
Brake
tubes
are

shaped
at

factory

to
secure

specified
clearance
and

may
not

require
reshaping
Discard

if

they
call
for
excessive

reshaping

b
In

reshaping
a
brake
tube
take
care

to
avoid

damaging
galvanization
or

collapsing
section

Mter
brake
lines
have
been

asssem

bled
check
to
make
sure
that
all

fittings
and
flare
nu
Is
ale

lightened
to

correct

torques

Tightenint
torque

Brake
tube
to
connector

I
Ston

kg
m

II
to

13
ft
Ib

Brake
tube
to
brake
hose

1
7
to

2
0

kg
m

12
to
14
ft
lb

Connector
and

clip
fixing
bolt

O
3S
to
O
4S

kg
m

2
5

to
3
3

ft
lb

3

way
connector

fixing
bolt

on
rear

axle
case

0
8
to
1
1

kg
m

6
to
8
ft
lb

N
L
S
V

DESCRIPTION

The

Nissan
Load

Sensing
Valve

N
L
S
V

serves
to

change
braking

power
of
the

rear
wheels
in

response

to

changes
in
the
load
and
fluid

pressure
improving
braking
stability

and

shortening

stopping
distances
Brake

System

The
N
L
S
V

is
installed
on
the

frame

being
inclined
at
10

degrees
A
summary
of

the
N

L
S
v

operation
is

given
in

Figures
BR
14

and
BR
15

r
Master

cylinder
TI
II

I

y

1

J

I

l
Attaching
angle

D

Wheel

cylinder

BR928

Fig
BR
14
Construction

of
N
L
S
V

Performance
curve
of
brake
fluid

pressure
is
as

follows

0

S

c
A

0

C

o

l
0
oadea

U1U

Front
wheel

cylinder

fluid

pressure
BR769

Perfonnance
curve

of
fluid

pressure
Fig
BR
15

N
L
S
V
TEST

the

following
occurs

When
rear
wheels
lock

stopping

distance
is
shorter
than
13
1

m
43

0

ft
whether
loaded
or
unloaded

Stopping
distance
should
be

measured

from
the

place
where
the
brake

pedal

is

first

applied
to
the

place
the
vehicle

actually

stops
Front
wheels
lock

simultaneously
with
or
ahead
of
rear

wheels
Operating
test

The

test
should
be
conducted
under

these
conditions

Drive
a
vehicle
with

pay
load
and

then
with

only
driver
on

a

dry
flat

concrete
or

asphalt
road

applying
the

brake
suddenly
at
40
km

h
25
MPH

N
L
S
V
is

functioning
normally
if

BR
9

Ibove
mentioned

st
is
available
when
op

the

FRONT
BRAKE
Brake

System

entire
brake

system
except

N

L
S
V
is

correctly

adjusted

After
shoe
return

spring

Adjuster
assembly

8

Adjuster
head

9

Adjuster
head
shim

10
Lock
spring

11

Adjuster
housing

12

Adjuster
wheel

13

Adjuster
screw

14

Retaining
spring

15
Lock

plate

16

Adjuster
shim

17
Rubber
boot
1
Brake

disc

2
Brake

shoe
assembly

3
Wheel

cylinder
assembly

4

Brake
shoe

upper
return

spring

5
Brake
shoe
lower

return

spring

REMOVAL

I
Jack

up
front
of
vehicle

just
high

enough
to
remove
tire
and

support
it

with

safety
stands

2

Remove
wheel

and
brake
drum
If

brake
drum
cannot
be

easily
removed

return
brake

adjuster
install
two
bolts

M8
x
1
25
in
holes
on
the

flange
face

of
brake
drum

and

tighten
bolts
even

ly
until
brake
drum
is
driven
out

3
In
order
to

ease

operation
re

move
hub

assembly
from
knucRle

spindle
Refer
to
Front
Axle

4

Unhook

upper
lower
and
after

shoe
return

springs
and
then
remove

brake
shoe
assemblies

S
Disconnect
brake
hose
from

wheel

cy
linder

6
Loosen

securing
nut
and
remove

wheel

cylinder

7
Remove
rubber
boot

adjuster

shim
lock

plate
and

retaining
spring

and
then
remove

adjuster
assembly

from
brake
disc
Fig
BR
I

6
Front
brake

1
Brake
hose

2
Wheel

cylinder
attaching

bolt

BA312

3
Rubber
boot

Fig
BR
17

Removing
wheel

cylinder

DISASSEMBLY
AND

ASSEMBLY

Wheel
cylinder

@

rr
l

@

t

a

Wheel

cy
linder

housing

2
Piston

3
Piston

cup

4
Dust

cover

5
Retainer
BR649

6
Connector

7

Packings

8
Connector
bolt

9
Bleeder

screw

10

Bleeder

cap
Wheel
cylinder
can
be

disassembled

simply
by
the

following
procedures

described
below

Remove
retainer
and
dust
cover

and
take
out

piston
from
wheel
cyl

inder
Be

careful
not
to

damage

sliding

part
of

piston
and

piston
cup

Thoroughly
wa
sh

u
disassembled

parts
in

brake
fluid
or
alcohol

Note
Do

not
wash
rubber

parts
with

mineral
oil

since
they
are
deterio

rated

When
alcohol
is
used
however
do

not
immerse
rubber

parts
in
alcohol

longer
than
30
seconds
After

parts

are
cleaned

dry
them
with
com

pressed
air

Assemble
wheel

cylinder
in

reverse

sequence
of

diassembly

When

securing
connector
bolt
in

sert
its
location

tip
to
the
hole
of

wheel

cylinder
firmly
and

tighten
it

securely

Carry
out

operations
carefully
so

that

component
parts
are
not
damaged

or
no
dust
and
other

foreign
materials

enter

cylinder

Note

The
brake
wheel

cylinder
is

available

in
both
NABCO
make
and

TOKICO
make
There
is

no
inter

changeability
of

repair
kits
or
com

ponent
parts
between
NABCO
and

TOKICO
makes

When

replacing
the

repair
kit
or

ent

parts
ascertain
the

brand

of
the
brake
wheel

cylinder

body
Be
sure
to
use

parts
of
the

same
make
as
the
former
ones

INSPECTION

Brake
drum

I

Replace
brake
drum
whose
dia

meter
is

beyond
the
limit
of

1
5
mm

0
OS9
in
with

respect
to
the

standard

inner
diameter
of
2S4
0
rom
10
00

SR
tO
Fig
BR
18
Front
wheel

cylinder
in

2
The
allowable
maximum

out
of

round
of
brake
drum
is
0
02

mm

0

0008
in

Re

condition
or

replace
brake
drum

if

specified
limit
is
exceeded

3

Measure
for

tapered
brake
drum

If

specified
limit
of
0

02
mm
0

0008

in
is

exceeded
as
measured
at

a

position
where
the
distance
of
4S
mm

177
in
is

kept
away
from
inlet

re
condition
or

replace
brake
drum

4

Contact
surface
with
which

linings
come
into

contact
should
be

finished
to

such
an
extent
that
it
is

ground
by
a
No
120
to
150
sand

paper

S

Using
a
drum

racer
finish
brake

drum

by
machining
if
it

shows

any

sign
of
score
marks

partial
wear
or

stepped
wear
on
its
contact
surface

Note
After
brake
drum
is

completely

re
conditioned
or
renewed
check

drum
and
shoes
for

proper
contact

pattern

Brake

assembly

I
When
brake
shoe

linings
are

cracked

incompletely
seated
uneven

Iy
worn

andlor
deteriorated
due
to

excessive

heating
or
soiled
with

oil

grease
and
brake
fluid

replace

2

Replace
linings
if
the
thickness
is

worn
down
to
less
than
1
0
mm
0
039

in

Note

When
brake
shoe

lining
is
in

stalled

grind
brake
shoe

lining
face

to
diameter

equal
to
that
of
brake

drum

lining
dimension

Width
x
Thickness
x

Length

4S
x

4
S
x

244
mm

1
77
x
0

177
x

9
61
in

3

Check

adjuster
for
smooth

oper

ation

4

Replace
shoe
return

springs
which

are
broken
or

fatigued
Brake

System

Standard
dimensions
of
shoe

springs

Free

length
Dia

of

spring
No
of
Installed

Item

lengthlload

mOl

in
mOl
in

coils

mm

kg
in
lb

Upper
136
5

2
0
0

079
37
IS9
S
14

to
16

S

37
6
28
31

to
3S

Lower
134
S

2
3
0
091
35
IS9
5
21

to
23

5
30
6
28
46
to

Sl

After
shoe
83
2

1
4
O
OSS
27
S
99
4

to
S

3
28
3

90
9
to
II

Wheel

cylinder

I

Replace

any
cylinder
or

piston

which
is
scratched
scored
or
worn
on

its

sliding
contact
surface

2

Replace
worn

parts
if

piston
to

cylinder
clearance
is

beyond
O
IS
mm

0
OOS9
in

Wheel

cylinder
inner
diameter

19
0S
mOl

Y
in

3

Replace
piston
cup
which
is

worn

or
otherwise

damaged

4

Replace
if

contacting
face
of

cyl

inder
and
shoe
is
worn

locally
or
in

step

S

Replace

damaged
dust
cover

fatigued
piston
spring
or

faulty

threaded

parts

6

Replace
tube
connector
which
is

worn
on
its

threaded

portion

INSTALLATION

Install
front
brake
in
the

reverse

sequence
of
removal

paying
particular

attention
to
the

following
instructions

I

When

assembling
adjuster
assem

bly

apply
brake

grease
to

adjuster

housing
bore

adjuster
wheel
and
ad

juster
screw

When
installing
adjuster

assembly

to
brake
disc

apply
brake

grease
to

disc

adjuster
and

retaining
spring
slid

ing
surfaces

to
slide

adjuster
smoothly

Measure

adjuster
sliding
resistance

Adjust
by
adjuster
shim
when

sliding

resistance
is

in
rrect

BR
ll
Adjuster
sliding
resistance

S
to

12

kg
II
to
261b

2

When

installing
wheel

cylinder
be

sure
to
secure
the

cylinder
with
R

mark

to
right
hand
disc
and
the
one

with
L
mark
to

left
hand
disc

Otherwise
brake
hoses

may
interfere

with
other

adjacent
parts
As

to
the

connecting
instructions

of
brake
hose

no
twist
or

contact
is
existed
on

brake

hose

referring
the

related

topic
Brake

line

Tightening

torque

Wheel

cylinder

SA
to

6
6

kg
m

39
to
48
ft

lb

Connector
bolt

1
9
to
2
5

kg
m

14
to
18
ft
Ib

Brake
hose

1
7
to
2

0

kg
m

12
to
14
ft
lb

Air
bleeder

0
7

to
0
9

kg
m

5
to
7
ft

Ib

Brake
disc

4
2

to
S
O

kg
m

30

to
36
ft
lb

3

Before
installing
brake
shoe
as

semblies

apply
brake

grease
to
wheel

cylinder
and

adjuster
brake
shoe
in

stalling
grooves
and
brake
disc
and

brake
shoe

assembly
contact
faces

two

places
Exercise

care
not
to

allow

grease
to

come
into
contact
with

linings
and

adjuster

BA313

Fig
BR
19
Greasing

points

REAR
BRAKE
Brake

System

4

Adjust
brake
shoe
clearance
and

bleed
brake

system
Refer
to
the

instructions
under

topic

Adjustment
in

this
section

Upon
completion
of
the
above
ad

justments
make
sure
that
brake

oper

ates

correctly
and
no
brake

fluid
leaks

BA315

REMOVAL

I
Jack

up
rear
of
vehicle

just
high

enough
to
remove
lire
and

support
it

with

safety
stands

2
Remove
wheel
loosen

hand
brake

and
detach
brake
drum

3
Turn

pin
by
900
and
remove

antirattle

springs

4

Open
brake
shoe
assemblies
out

ward

against
return

spring
and
remove

extension
link

S

Remove
return

springs

6
Remove
brake
shoe
assemblies

Note

that
after

secondary
brake
shoe

assembly
must
be

separated
from

toggle
lever
When

separating
after

secondary
brake
shoe

assembly
from
toggle
lever
withdraw
clevis

pin

7
Disconnect

toggle
lever
from

hand
brake
rear
cable

BR316

Fig
BR
21

Remouing

toggle
leuer

BR
12
1

Brake
disc

2
Brake
shoe

assembly

3
Wheel

cylinder
assembly

4
Return

upper
spring

5
Return
lower

spring

6
After
shoe
return

spring

7
Retainer

8
Antirattle

spring

9

Spring
seat

10

Adjuster
assembly

11

Adjuster
head

12

Adjuster
head
shim

13
Lock

spring

14

Adjuster
housing

15

Adjuster
wheel

16

Adjuster
screW

17

Toggle
lever

18

Extension
link

19

Return
spring

20

Adjuster
spring

21
Lock

plate

22

Adjuster
shim

23
Rubber
boot

24
Antirattlc
pin

Fig
BR

20
Reor
brake

8
Disconnect
brake
tube
at
wheel

cylinder
by
loosening
flare
nut

9
Remove
wheel
cylinder
from

brake
disc

by
loosening
installation

nuts

10
Remove
rubber
boot

adjuster

shim
lock

plate
and

adjuster
springs

and
remove

adjuster
assembly
from

brake
disc

DISASSEMBLY
AND

ASSEMBLY

Wheel

cylinder

Remove
dust
cover
and

pull
out

piston
head
and

piston
assembly

Refer
to
Wheel

Cylinder
of

Front

Brake

CD

l
ID

345

0

1
Dust

cover

2

Piston
head

3
Piston

4

Piston
Cll

p

5

Wheel

cylinder

housing

6

Bleeder

cap

7

Bleeder
screw

8

Connector

9
Washer

10
Connector
bolt
BR318

Fig
BR
22

Rear
wheel

cylinder

INSPECTION

Brake
drum

Check
brake

drum
in

the
same

manner
as

outlined
in
the
Front
Brake

Drum

Brake

assembly

I
When

brake
shoe

linings
are

cracked

incompletely
seated
uneven

ly
worn
andlor
deteriorated
due
to

excessive

heating
or

soiled
with
oil

grease
and
brake
fluid

replace

2

Replace

linings
if
the
thickness
is

WOol
down

to
less
than

1
0
rom
0
039

in

Note
When
brake

shoe

lining
is
in

stalled

grind
brake

shoe

lining
face

to
diameter

equal
10

lha
I

of
brake

drom

Lining
dimemion

Width
x
Thickness
x

Length

4S

x
4

5
x
244

rom

1
77
x
0
177
x
9
61
in
Brake

System

3
Check

adjuster
for
smooth

oper

ation
4

Replace
shoe
return

springs
which

are

broken
or

fatigued

Standard
dimensions

of
shoe

springs

Dia
of

spring
No

of
Installed

Free

length

lengthlload
Item

mOl
in

mOl
in

coils

mmlkg
in
lb

175

2

0
0
079
32
5
184
11
to
13

Upper

6
89

7
24
24
to
29

158

2
3

0

091
30
176
18

to
20

Lower

6
22

6
93
40
to
44

83
2

1
4
0
055

27
5
99
4

to
S

After
shoe

3
276

3

90
9

to

II

20
5

1

6
0
063
3
5
12
3

S
to
4
5

AntiratUe

0
807

0
47
8
to
9
9

Wheel

cylinder

I

Replace
any
cylinder
or

piston

which
is

scratched
scored
or
worn
on

its

sliding
contact
surface

2

Replace
worn

parts
if

piston
to

cylinder
clearance
is

beyond
O
IS

rom

0

00S9
in

Wheel

cylinder
inner

diameter

19

0S
rom

Xin

3

Replace
piston
cup
which

is
worn

or

damaged

4

Replace
if

contacting
face
of

cyl

inder

and
shoe

is
worn

locally
or
in

step

5

Replace
damaged
dust

cover

fatigued
piston
spring
or

faulty

threaded

parts

6

Replace
tube
connector
which
is

worn
on
its
threaded

portion

INSTALLATION

Install
rear

brake
in

the
reverse

sequence
of
removal

paying
particular

attention

to
the

following
instructions

I

Rear

adjuster
assembly
is

the

same
as
front
Refer
to
the

paragraph

covering
Front
Brake
Installation

Adjuster
sliding
resistance

S
to
12

kg
II
to
261b

BR
13
2

When

assembling
toggle
lever

and

after
brake
shoe

assembly

adjust
clear

ance
between

toggle
lever
and

after

brake
shoe

assembly
to
0
to
0
3
mOl
0

to
0

012
in
with

a

properly
selected

toggle
pin
washer

Toggle

pin
washer

No

Thickness
rom
in

I
2
0
0
079

2
2
3
0
091

3
2

6
0
102

4
2
9
0
114

S

3
2
0
126

3

Before
installing
brake
shoe

as

semblies

apply
brake

grease
to
the

following

places

1
Brake
shoe

installing
grooves
of

adjuster
and
wheel

cylinder

2
Extension
link

installing
grooves

3
Lower
surface
of

spring
seat

4

Contact
surfaces
between
brake

disc
and
brake
shoe

assembly
six

places

At
this
time

be
sure
not
to
coat

brake

grease
to
brake

linings

f

BR317

Fig
BR
23

Gre
ing
point

4

Tightening

torque

Wheel

cylinder

J
S
to
1

8

kg
m

II
to

13ft
Ib

Connector
bolt

1

9
to
2
5

kg
m

14
to
18
ft
Ib

Brake
tube

1
5
to
1

8

kg
m

II

to
13

ft
Ib

Air
bleeder

0
7
to
0
9

kg
m

S

to
7
ft
Ib

Brake
disc

5
4

to
6
4

kg
m

39
to
46
ft

Ib

S

Adjust
brake
shoe
clearance
and

bleed
brake

system
Upon
completion

of

the
above

adjustments
make
sure

that
brake

operates
correctly
and
no

brake
fluid
leaks

MASTER
VAC

DESCRIPTION

A
vacuum

suspended
Master
Vac

is

installed
behind
the

master

cylinder

As
the

brake

pedal
is

depressed
fluid

is

forced
under

high
pressure
through

the
brake

pipes
to
the
wheel

cylinders

to
retard

or

stop
the

vehicle

The
Master
Vac
contains

a

spring

loaded

diaphragm
of
IS2
4

mm
6
in

in

diameter
It

operates
on

negative

pressure

produced
n
the

engine
intake

manifold

The
tandem

master

cylinder
is

capable
of

producing
high
pressure

even
if
the
Master
Vac
is

faulty
Brake

System

Note
The
Master
Vac

diaphragm
dif

fers
from
fonner
ones
for

improved

braking
force
Do
not
install
fonner

Master
Vac
on
1976
models
The

1

Plate
and
seal

2
Push
rod

3

Diaphragm

4

Rear
shell

5

Diaphragm

plate
Master
Vacs

are
identified

by
the

label
color
as
follows

1976
model
Caution

Label

Former
models
YeJlow

BR321

11

Valve

operating
rod

12
Valve

return

spring

13

Poppet
return

spring

14
Exhaust
valve

15
Valve

plunger

16
Reaction

disc

17

Diaphragm
return

spring

18
Front
shell
6
Seal

7

Vacuum
valve

8

Poppet
assembly

9
Valve

body
guard

10
Air

silencer
filter

INSPECTION
OF

OPERATION

Checking
yscuum

pressure

I
Connect

a
vacuum

gauge
in
the

line
between
check
valve

and
Master

2
Start

engine
and
increase

engine

speed
Stop
engine
when
vacuum

gauge
indicates
SOO

mmHg
19
69

inHg

BR
14
Fig
BR
24
Sectionall1iew

of
Master
Vac

Vac
as

shown
in

Figure
BR
25

1

Check
valve

2

Vacuum

gauge

BA169

Fig
BR

25
Air

tight
t
t
t

up

Air

tight
test

I
Fifteen

seconds
after

engine
is

stopped
observe
the

rate
of

drop
in
air

pressure
registered
by
vacuum

gauge

If
a

pressure
drop
of
25

mmHg
0
98

inHg
is

exceeded
refer
to
the
follow

ing
chart
to
determine
the
cause
of

failure

Probable
cause

I
Air

leakago
at
check
valve

2
Air

leakage
a

t

push
rod
seal

3

Air
leakage
between
valve

body
and

seal

4
Air

leakage
at
valve

plunger
seat

5

Damaged
piping
or

joints

2
Fifteen

seconds
after

engine
is

stopped
and
brake

fully
applied
ob

serve
the

rate
of

drop
in
air

pressure

registered
by
vacuum

gauge

Probable
cause

1
Air

leakage
at
check
valve

2

Damaged
diaphragm

3
Reaction
disc

dropped
off

4
Air

leakage
at

and
valve
body
poppet
assembly
seat

Note
When

replacement
of

any
part

is

required
be
sure
to
renew

Master

Vac
as
an

assembly

Inspecting
check
valve

Remove

clip
and
disconnect
hoses

at
connections

The
check
valve

can

now
be
removed

yr

BA3

Fig
BR
26
Location

of
check
valve

2

Using
a
Master

Vac
tester

apply
a

vacuum

pressure
of

200

mmHg
7
87

inHg
to

the

port
of
check

valve
on
the

Master
Vac
side
If
a

pressure
drop
of

10

mmHg
0
39

inHg
is
exceeded
in
1

I

I

17
I

f
I

I
I

Z
I

I
y1
I

I
I
7
I
I
I

I
I
I

I
I
I

I

y1
II

I

I
I
I
I
I

I
L
I
L

5
to
15

20
25
30
35
40

45
50

55
60

22
44

66

88
110
132

Pedal

operating
force

kg
lb
BR772

Fig
BR
28

Performance
curves

of
Master
Vac
Brake

System

Corrective
action

Replace
check
valve

Replace
seal

Repair
or

replace
faulty

partes

Repair
or

replace
seat

Repair
or

replace

If
a

pressure
drop
of
25

mmHg

0

98

inHg
is

exceeded
refer
to

the

following
chart
to
determine
the
cause

of

failure

Corrective
action

Replace
check
valve

Replace

Reinstall
and
check

push
rod

for

proper
turn

Replace

faulty
part
s

15
seconds

replace
check
valve
with
a

new
one

3
When

pressure
is

applied
to
the

Master
Vac
side
of
check

valve
and

valve
does
not

open
replace
check

valve
with
a

new
one

120
I

7IG

110
1
560

100

I
420

i
90
1
280

I

u

80
1
140

70
1
000

II

60
850

0

0

5

a
50
710

40
570

30
430

20
280

10
140

BR
15
1

I

Manifold

side

Master

Yac
side

1

Spring
2

Valve

BA289

Fig
BR

27
Sectional
view

of
check

valve

Operating
test

1
Connect

an
oil

pressure
gauge
in

brake
line

at
connection
on
master

cylinder

2
Install
a

spring
scale
on
brake

pedal

3

Start

engine
and
increase

engine

speed
until

a
vacuum

pressure
of
500

mmHg
19
69

inHg
is

registered
on

vacuum

pressure

gauge
With
a

vacuum

pressure
of
500

mmHg
19
69

inHg

held

measure
an
oil

pressure
with

respect
to

each

pedal

operating
force

Relationship
between
oil

pressure

and

pedal

operating
force
is
illustrated

in

Figure
BR
28
If

test
results
are
not

as

specified
in

Figure
BR
28
check

Master
Vac
for
condition
in

a
manner

as
described
under

Inspection
before

removal
of
this
unit

Also
check
brake
line
for
evidence

of
fluid

leakage

Note
Determine
whether
malfunc

tion
occurs
in
Master
Vac
or
in

check
valve

Always
inspect
check

valve
fiTlit