Rear quarter panel or tonneau

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

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

50Repair 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

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.