1977 DATSUN PICK-UP brake fluid

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

Condition

Excessive

pedal
travel

Spongy

pedal

Poor

braking
effect

Brakes

drag
Brake

Syst
em

TROUBLE
DIAGNOSES
AND
CORRECTIONS

Probable
cause

Low
brake
1uid
level
or

empty
master

cylinder
reservoir

Leakage
in
master

cylinder

Deteriorated
check
valve

Air
in

system

Faulty
brake

adjustment

Low

1uid
level
in
master

cylinder

Air
in

system

Faulty
brake

adjustment

Reservoir
filler

cap
vent

hole

clogged

Swollen
hose
due
to
deterioration

or
use
of

poor
quality
hose

Distorted

brake
shoes
or

excessively
worn

or

cracked

brake
drum

Soft
or
swollen

caliper
seals

Use
of
a
brake

1uid
with

too
low

boiling

point

Fluid

leakage
in

brake
lines

Low

brake
1uid
level

or

empty
master

cylinder
reservoir

Air
in

brake
lines

Excessive
shoe
ta
drum

clearance

Grease
oil

mud
or

water
on

linings
or

pads

Deterioration
of

linings
or

pads

Local
fit
of

linings
or

pads

Linings
or

pads
excessively
worn

Master

cylinder
or
wheel

cylinders
in

poor

condition

Binding
mechanical

linkage
at
brake

pedal

and
shoes

Clogged
brake
lines

Incorrect

adjustment
of

wheel

bearings

Improper
shoe
t

drum
clearance

Weak
shoe
return

springs

No
free
travel
in

brake
shoe

return

BR
22
Corrective
action

Fill
and
bleed
as

necessary
Test

for
source

of

leakage
by
examining
all
lines

connec

tions

and
wheel

cylinder

Overhaul
master

cylinder

Replace
check
valve
and
bleed

system

Bleed

system

Adjust
shoe
to
drum
clearance

Inspect

auto

adjuster
operation

Top
with
1uid
and

inspect
for

leakage

Correct
as

necessary

Adjust
shoe
to

drum
clearance

Inspect

aut

adjuster

operation

Clean
and

bleed

system

Replace
hose
and

bleed

system

Replace
faulty

parts

Drain

hydraulic
system
flush
with
alcohol

and

replace
all
seals

Replace
with

specified
brake

1uid
and
bleed

system

Check

master

cylinder

pIpIng
and
wheel

cylinder
for
leaks
and

repair

Fill
and
bleed

as

necessary

Bleed

system

Adjust

Clean
brake
mechanism
and
check
for

cause

of

problem

Replace
linings
or

pads

Replace

Shave
or

replace

Replace

Repair
or

replace

Free

up
as

required

Check
and

clean

Adjust
or

repair

Adjust

Replace

Adjust

pedal
height

Condition

Brake
chatters

Brake

squeals

Pedal

pulsates

Brakes
fade

Brakes

drag

Unbalanced
brakes
Brake

System

Probable
cause

Groove

or
out
of

round
brake
drum

Loose

or
bent

brake

disc

Distorted
brake
shoes

or

pads

Grease
or
brake
fluid
on

linings

Dirty
or
scored
brake

drums

Distorted
brake
shoes
or
bent

support
plate

Weak
or
broken
brake
shoe

retaining
spring

or

return

spring

Glazed
or
contaminated
brake

lining

Out
of

round
or
off
center
drum

Brake
fluid
has
too
low

boiling
point

Use
of

improper
linings
or
brake

linings
are

contaminated

Brake
drums
are
out
of
round

Hydraulic
connections
master

cylinder
and

wheel

cylinders
are

corroded
or

damaged

Bleed
screw
is

open

Pedal

linkage
is

binding
or

push
rod

adjust

ment
is
too

long

Master

cylinder
compensator
part
is
ob

structed

Seized
master

cylinder
piston

Poor
shoe
condition

Poor

wheel
cylinder
condition

Deformation
of

piston
cups

Hand
brake
will
not
return

Clogged
master

cylinder
return

port

Improper
tire
inflation

Improper
adjustment
of
shoe

to
drum
clear

anee

Grease
oil
mud
or
water
on

linings
or

pads

Mud
in

brake
drum

Deterioration
of

linings
or

pads

Excessive
wear
of

linings
or

pads

BR
23
Corrective
action

Grind
or

replace
as

required

Tighten

support
plate
bolts
to

specified

torque
or

replace
plate

Replace
as

necessary

Replace
linings

Blowout

assembly
with

compressed
air
or

refinish
drum

Replace
faulty
unit

Replace
if

faulty

Cam

ground
lining
to
eliminate

glaze
If

it

doesn
t

replace
linings

Turn

drum
or

replace
as
necessary

Drain
and
fill

system
with

approved
fluid

Replace
linings

Repair
or

replace
as
necessary

Repair
as
necessary

Close
screw
and
bleed

system

Lubricate

linkage
check

pedal
return

spring

for
condition
and

adjust
push
rod

as
neces

sary

Blowout

foreign
matter
with

compressed

air

Disassemble
master

cylinder
and

replace

piston
Bleed

system

Clean
and

repair

Repair
or

replace

Replace

Check
and

repair

Clean

Inflate
to
correct

pressure

Readjust

Clean
brake

mechanism
and
check
for
cause

of

problem
Replace
linings
or

pads

Clean

Replace

Replace