Assembly
This is integral with the side frame assembly and
has both inner and outer construction. The inner
construction comprises the rear wheel arch and
the rear seat heelboard assembly. This provides
the support for the rear seat squab in a saloon
car; if the vehicle is a hatchback or estate car,
the two back seats will fold flat and the seat
squabs will not need support. This area is known
as the rear bulkhead of the car; it gives additional
transverse strength between the wheel
arch sections and provides support for the rear
seat. The rear bulkhead also acts as a partition
between the luggage and passenger compartments
(Figure 1.47).
Rear wheel arch assembly
This assembly is constructed as an integral part of
the inner construction of the rear quarter panel. It is
usually a two-piece construction comprising the
wheel arch and the quarter panel, which are welded
together (Figure 1.46).
Wings
A wing is a part of the body which covers the
wheel. Apart from covering the suspension construction,
the wing prevents water and mud from
being thrown up on to the body by the wheels. The
front wings (or the fender assembly) are usually
attached to the wing valance of the front end
assembly (see Figure 1.45) by means of a flange
the length of the wing, which is turned inwards
from the outer surface and secured by either
welding or bolts. Adjustment for the front wing is
usually provided for by slotting the bolt holes so
that the wing can be moved either forwards or
backwards by loosening the attaching bolts. This
adjustment cannot be made if the wing is welded
to the main body structure.
In some models the headlights and sidelights
are recessed into the front wing and fastened in
place by flanges and reinforcement rims on the
wing. Any trim or chrome which appears on the
side of the wing is usually held in place by special
clips or fasteners which allows easy removal of
the trim.
The unsupported edges of the wing are swaged
edges known as beads. The bead is merely a flange
which is turned inwards on some cars and then up
to form a U-section with a rounded bottom. It not
only gives strength but prevents cracks developing
in the edges of the wing due to vibration, and it
provides a smooth finished appearance to the edge
of the wing.
In general the rear wing is an integral part of the
body side frame assembly and rear quarter panel.
When the wing forms an integral part of the quarter
panel, the inner construction is used to form
part of the housing around the wheel arch. The
wheel arch is welded to the rear floor section and
is totally concealed by the rear quarter panel, while
the outer side of the wheel arch is usually attached
to the quarter panel around the wheel opening.
This assembly prevents road dirt being thrown
upwards between the outer panel and inner panel
construction.
Doors
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Several types of door are used on each vehicle
built, although the construction of the various
doors is similar regardless of the location of the
door on the vehicle, as indicated on Figure 1.47.
The door is composed of two main panels, an outer
and an inner panel, both being of all-steel construction.
The door derives most of its strength
from the inner panel since this is constructed
mainly to act as a frame for the door. The outer
panel flanges over the inner panel around all its
50 Repair of Vehicle Bodies
edges to form a single unit, which is then spot
welded or, in some cases, bonded with adhesives to
the frame.
The inner panel has holes or apertures for the
attachment of door trim. The trim consists of the
window regulator assembly and the door locking
mechanism. These assemblies are installed through
the large apertures in the middle of the inner panel.
Most of the thickness of the door is due to the
depth of the inner panel which is necessary to
accommodate the door catch and window mechanism.
The inner panel forms the lock pillar and
also the hinge pillar section of the door. Small reinforcement
angles are usually used between the
outer and inner panel, both where the lock is
inserted through the door and where the hinges are
attached to the door. The outer panel is either provided
with an opening through which the outside
door handle protrudes, or is recessed to give a
more streamlined effect and so to create better
aerodynamics.
The upper portion of the door has a large opening
which is closed by glass. The glass is held
rigidly by the window regulator assembly, and
when raised it slides in a channel in the opening
between the outer and inner panels in the upper
portion of the door. When fully closed the window
seats tightly in this channel, effectively sealing out
the weather.
Boot lid or tailgate
This is really another door which allows access
to the luggage compartment in the rear of the car
(Figure 1.46). A boot lid is composed of an outer
and an inner panel. These panels are spot welded
along their flanged edges to form a single unit in
the same manner as an ordinary door. The hatchback
and estate car have a rear window built into
the boot lid, which is then known as a tailgate.
Some manufacturers use external hinges, while
others use concealed hinges attached to the inner
panel only. A catch is provided at the lower rear
edge of the boot lid or tailgate and is controlled
by an external handle or locking mechanism.
This mechanism may be concealed from the eye
under a moulding or some type of trim. In some
models there is no handle or external locking
mechanism; instead the hinges are spring loaded
or use gas-filled piston supports, so that when
the lid is unlocked internally it automatically
rises and is held in the open position by these
mechanisms.
Bonnet
The bonnet (Figure 1.45) is the panel which covers
the engine compartment where this is situated
at the front of the vehicle, or the boot compartment
of a rear-engined vehicle. Several kinds of
bonnets are in use on different makes of cars. The
bonnet consists of an outer panel and an inner
reinforcement constructed in the H or cruciform
pattern, which is spot welded to the outer skin
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panel at the flanged edges of the panels. The reinforcement
is basically a top-hat section, to give
rigidity to the bonnet. In some cases the outer
panel is bonded to the inner panel using epoxy
resins. This system avoids the dimpling effect on
the outer surface of the bonnet skin which occurs
in spot welding.
Early models used a jointed type of bonnet
which was held in place by bolts through the centre
section of the top of the bonnet into the body of the
cowl and into the radiator. A pianotype hinge was
used where the bonnet hinged both at the centre
and at the side.
The most commonly used bonnet on later constructions
is known as the mono or one-piece
type, and can be opened by a variety of methods.
On some types it is hinged at the front so that the
rear end swings up when the bonnet is open.
Others are designed so that they can be opened
from either side, or unlatched from both sides
and removed altogether. Most bonnets, however,
are of the alligator pattern, which is hinged at the
rear so that the front end swings up when
opened.
The type of bonnet catch mechanism depends on
the type of bonnet used. When a bonnet opens
from the rear the catch mechanism is also at the
rear. When it opens from either side the combination
hinge and catch are provided at each side. The
alligator bonnets have their catches at the front,
and in most cases the catches are controlled from
inside the car.
Bonnets are quite large, and to make opening
easier the hinges are usually counterbalanced by
means of tension or torsion springs. Where smaller
bonnets are used the hinges are not counterbalanced
The history, development and construction of the car body 51
and the bonnet is held in place by a bonnet stay
from the side of the wing to the bonnet. Adjustment
of the bonnet position is sometimes possible by
moving the hinges.
Trims
Some details of exterior and interior trims are
shown in Figures 1.48 and 1.49.
Complete body shell
A contemporary vehicle embracing all the latest
techniques of panel assembly is shown in Figures
1.50 and 1.51. Figure 1.50 illustrates the completed
structure with all panel assemblies in place.
Figure 1.51 shows the completely finished vehicle
ready for the road.
