lane assist DATSUN B110 1973 Service Repair Manual

BODY

UNDERBODY
ALIGNMENT

CONTENTS

UNDERBODY
GENERAL
SERVICE

INFORMATION

ALIGNMENT
CHECKING
PROCEDURE
BF
9

BF
9

UNDERBODY
GENERAL

SERVICE

INFORMATION

Since
each

underbody
component
directly
affects
the

overall

strength
of
the

body
it
is
essential
that

proper

welding
sealing
and
rust

proofing
techniques
be
observed

during
service

operations

Whenever
the

body
is

repaired
be

sure
to
provide
the

repaired
body
parts
with

rust

proof

In
the

case
of
a

rust

proofmg
critical

underbody

component
it
is
essential
that
a

good
quality
type
air

dry

primer
such
as
corrosion
resistant
zinc
chromate
be
used

Do

not
use
combination

type
primer
surfacers

ALIGNMENT
CHECKING

PROCEDURE

Misalignment
in
the

underbody
affects
the
front

fender
door
trunk
lid

and
window

alignments
and
also

the
tail

gate
and
rear

body

opening
alignments
in
the

case

of
a
station

wagon
or
van

Underbody
misalignment

particularly
affects

the

suspension
system
thereby
causing

various

problems
that
arise
from

suspension
misalignment

It
is
essential
that

underbody

components
be

aligned

within
the

specified
dimensions

given
in

Figures
BF
13
14

and
IS

In

the
event
of

collision
damage
it
is

important
that

underbody
a1ignrnent
be

thoroughly
checked
and
if

necessary
realigned
to
the

specified
dirnensions

There
are

many
tools
that

may
be

ernployed
to
correct

collision

damage
such

as
frame

straightening
machines

external

pulling
equipment
other
standard

body
jacks
PRINCIPLES
OF
TRAMMING

CAR
PREPARATION

TRAMMING
SEQUENCE
BF
9

BF
10

BF
10

To
assist
in

checking
alignment
of
the

underbody

components
repairing
minor

underbody
damage
or

locating
replacement
parts
the

following
underbody

dimensions
and

alignment
checking
information
are

presented

PRINCIPLES
OF
TRAMMING

All
reference
locations
shown
in

Figure
BF
13
14
and

15

are

symmetrical
at
the
centerline
of
the
vehicle
For

example
wheo

performing
a
crosHheck
of
the

body
floor

panel
dimensions

Figures
BF
I3
14

and
IS
the

diagonal
measurement
should
be
the

same
in
boflii

directions
Cross

checking

operations
are
used
to
deter

mine
the

relationship
between
two
locations
on
the

underbody

To

measure
the

distance
between

any
two

reference

points
on
the

underbody
accurately
two

specifications

are

required

I
The

horizontal
dimension
between
the
two

points
to

be

measured

2
The
vertical
dimension
from
the
datum

line
to
the

points
to
be
measured
For
an

example
the

diagonal

measurement
calculated
on
a
horizontal

plane
between

reference

points
of
dimension
line
L
shown
in

Figure

BF
I3
is
631
3
mm
24

8
in
The

specifications
from
the

datum

line
have
a
vertical

height
difference
of
11
6

mm

0
456
in
between
the

forward
location
of
dimension

L

at
vertical
dimension
80
0
mm
3
150
in
and
the

rearward
location
of
dimension
L
at

vertical
dimension

91
6
mm
3
606
in
The

vertical

pointer
used
at
the

forward
location
should

be

positioned
so
as
to
extend

11
6

mm
0
456
in

further
from
the
tram
bar
than
the

BF
9