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17-4
GROUP
17-BODY, DOORS AND WINDOWS
CHECKING BODY FOR
MISALIGNMENT
To align or
square
up a body, take
two opposite diagonal measurements
between pillars. Use a measuring
tram for these measurements. Take
the measurements between reference
points such as crease lines or weld
joints which are diagonally opposite
each other on the two pillars being
measured. Since all measurements
should be made
from
the bare metal,
remove all
interior
trim from the
checking points.
In some cases, it
is difficult to ob-
tain proper
body alignment
when
repairing a body
that
is
damaged
on both sides.
In
these cases,
hori-
zontal and vertical
measurements
can
he
taken from a
body of the
same
·
body
..
style.
Once these
b;~sic
dimensions are
taken
and established
on
the
damaged body.
alignment
can
be made
by
diagonal measurements
taken from points on
the two
pillars.
Do
not attempt to correct any
serious
misalignment
with one
jack-
ing operation. This is
particularly
true if other sections
of the body
also require aligning.
Align each
section
proportionately
until
the
proper dimensions are
obtained.
Door
openings are checked
in the
same
manner
as
the
body.
Horizon-
tal, vertical. and
diagonal
checking
points
are established
on
all
four
sides of the door opening
that is
being measured.
CHECKING
UNDERBODY FOR
MISALIGNMENT
The dimensions of the underbody
must be restored in the repair of
major body qamage, to provide cor-
rect front and rear wheel geometry
(Fig. 1). All the dimensions are
detailed to the centre line of exist-
ing holes in the underbody assembly.
Once the frame and suspension
members are aligned, the balance
of the repair can be performed.
PAINT REFINISHING
Acr~·
lic
Enamels.
Acrylic
enamels
exhibit better hardness.
mar resist-
ance and gloss retention
in metallic
colors than the ordinary enamels.
Acrylic enamels also
possess
the
property of good
polishability.
Following are
recommended re-
pair procedures for acrylic
enamels:
Repair By
Polishing.
Repair
of
minor
dirt or fallout. sags,
mars.
scratches.
dry
spray. overspray
and
orange peel can be accomplished
by
machine
or
hand
oolishing or
by
both sanding and polishing without
the necessity of repainting. Repairs of
this type should apply to an entire
panel while spot repairs should be
attemped on.Jy in isolated areas.
The suggested polish repair pro-
cedure consists of:
1. Remove the defect hy oil sand-
ing with 600 grit paper, using water
or mineral spirits as a lubricant.
2.
Apply a white or light colored
medium
grit
machine
polishing
compound to the painted surface
with a brush.
3. Polish the entire panel surface
using
an
I 850
rpm wheel and a car-
pet pad (approximately
%-inch
nap)
or lambswool pad.
4. Buff the
surface
with a clean
lambswool pad.
Normally.
acrylic
enamels do not
need polishing to improve their gloss;
however, the foregoing procedure
can he used to restore the original
luster to
the
film after weathering,
or to ill}prove the
surface
smooth-
ness of the finish on the entire car.
Repair By
Repainting. Acrylic
enamels can be repaired by repaint-
ing with either conventional air dry-
ing or low bake enamels, or with
acrylic
lacquers. When repainting
metallic colors, it is recommended
that acrylic lacquer be used since a
better color match can be obtained;
both the original finish and the re-
pair can be polished to provide the
same luster, and the air dry acrylic
repair lacquer will provide better
durability in service than air dry
enamels. Do not use Nitrocellulose
lacquers for exterior repairs.
When using any one of the three
types of repair materials over acrylic
enamel, remove all traces of wax,
polish or grease with a good sili-
cone
remov~r.
It is extremely im-
portant that a thorough sanding
of the original finish be accom-
plished using No. 400 grit paper.
Care should be exercised to ensure
that all surfaces; including edges
and
areas
adjacent
to
applied
mouldings, are thoroughly sanded
in order to provide adhesion of
the repair top coat. Areas saaded
to the base metal (cut through)
should be treated with an acid
cleaner. Follow the directions of
the supplier as stated on the con-
tainer.
After sanding, proceed with the
application of a primer surfacer re-
duced according to the supplier's
recommendations to any bare metal
spots
that have been exposed. After
the recommended air dry time, sand
the primer surfacer with No. 400
grit paper before application of the
repair material.
The lacquer or
enamel used should be reduced as
recommended by its supplier.
PAINT DEFECI'S AND REPAIR
PROCEDURES
Listed here are some of the ab-
normal paint conditions that may be
encountered
(Fig.
2). It is very im-
portant to identify the paint condi-
tio.:t correctly so that the proper
repair procedure may be followed.
For each of the following paint con-
ditions described, the recommended
repair procedure will be indicated.
BLISTERING
Blistering is the formation of bub-
bles or pin points on the surface of
the finished work. Unless inspected
by a magnifying glass, this condition
is very hard to identify. In some in-
stance;, this complaint may be con-
fused with dirt in the paint. To
verify blistering, prick the suspected
areas, and note whether a hole exists
under the bubble. This condition is
caused by rust, moisture, or oil be-
tween the coats, metal not properly
cleaned,
or uneven
temperatures
between the metal and' the paint
being sprayed.
Acrylic Enamel. Repair by re-
painting (color coat) . Priming pro-
cedure must first be followed if
defect is due to poor metal prepara-
tion.
CHECKING
Line checking has the appearance
of thin, straight lines criss-crossing
each other. These lines may be from
one-half inch to four inches or long-
er, increasing in length as the finish
ages.
Acrylic Enamel. Refinish panel.
(Color coat-primer if damaged.)
CHIPPING AND
STONE BRUISES
Chipping occurs when the surface
of the finish coat of paint has been
broken by a sharp blow, and small
p,articles of paint have flaked off.
Frequently, stone bruises result
in
chipping.
Acrylic Enamel. Refinish panel.
Paint may be spotted if in isolated
areas. (Prime to be bare metal.)
CRACKING
Cracking is evidenced by the
paint curling. Frequently, cracking
starts at the edge of the panel. This
is caused by poor mixing of paint
or by temperature changes during
the
various
painting stages.
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