26 Front pillar positioning notch (Inner side) LH
26a Front pillar positioning notch (Inner side) RH
39 Centre of rear door striker mounting hole (Upper section) LH _ 10 mm (0.393 in)
39a Centre of rear door striker mounting hole (Upper section) RH _ 10 mm (0.393 in)
48 Centre of hood opener cable routing hole LH _ 5.3 mm (0.208 in)
48a Centre of hood opener cable routing hole RH _ 5.3 mm (0.208 in)
49 Centre of front door striker mounting hole (Upper section) LH _ 12 mm (0.472 in)
49a Centre of front door striker mounting hole (Upper section) RH _ 12 mm (0.472 in)
Bonnet alignment
Bonnet alignment can be easily checked by visual
inspection. When the bonnet is closed the gap all
around it should be uniform; if it is not, misalignment
exists. Manufacturers specifications concerning
this gap are available; however, a good general
rule is that this clearance should be between 3 mm
and 6 mm wide. Correct bonnet alignment with the
wings and front grille preserves the streamlined
contours of the front end of a car. A uniform gap
should exist between the sides of the bonnet and
the wings. At the rear end of the bonnet the body is
recessed to form the scuttle panel into which the
bonnet fits to give a continuous flowing line. If the
bonnet is too high or too low a recognizable step
occurs at this point. If the bonnet is too far forward
Major accident damage 447
Figure 14.73 Side body check
No. Standard measurement point Hole-Size shape. mm (in)
25 Front pillar positioning notch (Upper section)
26 Front pillar positioning notch (Lower section)
27 Notch of roof side rail
28 Notch of front pillar outer and side sill outer
29 Centre pillar positioning notch (Lower section)
30 Centre pillar positioning notch (Upper section)
31 Notch of rear pillar outer and side sill outer
32 Notch of centre pillar outer and side sill outer
33 Rear pillar positioning notch (Upper section)
34 Rear pillar positioning notch (Lower section)
448 Repair of Vehicle Bodies
Figure 14.76 Upper body measuring system
measuring door aperture (Kroll (UK) Ltd)
Figure 14.77 Upper body measuring system
measuring sill panel (Kroll (UK) Ltd)
Figure 14.74 Complete upper body measuring
system (Kroll (UK) Ltd)
Figure 14.75 MacPherson strut measuring
(Kroll (UK) Ltd)
a large gap will exist between the rear of the
bonnet and the raised portion of the scuttle panel;
however, if the bonnet is too far back this gap will
be too small and there is a possibility that when the
bonnet is opened it will catch the scuttle panel and
chip the paint on either or both of these panels.
When a condition of misalignment exists that
affects the bonnet opening, it will be necessary to
X check the opening before deciding whether to
move either the wings or the grille panel. In some
cases this can be done by adjustment; in other
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cases, where these assemblies are fully welded,
Major accident damage 449
hydraulic equipment must be used. The bonnet
hinges on most cars are also constructed to give
adjustment; therefore the bonnet can be moved
forwards, backwards and sideways.
Boot lid alignment
Correct boot lid alignment exists when the boot
lid matches the contour of the body surrounding
panels. Misalignment of the boot lid is checked
visually by an inspection of the gap all round the
boot lid between it and the body. It is often necessary
to check more closely for boot lid alignment,
because an incorrectly aligned boot lid could
allow the entrance into the luggage compartment
of water and dust which might cause damage to
anything being carried there. A simple check is to
chalk the edges of the body flanges which contact
the weatherstrip on the boot lid, then close and
reopen the lid, thus transferring the chalk to the
weatherstrip at each point where contact is made.
If this chalk line is visible around the entire
weatherstrip, the boot lid sealing is perfect.
Where the chalk line does not appear, the boot lid
is not sealing properly and realignment will be
necessary. Realignment may be possible by
adjustment of the latch or hinges, but in some
cases it may be necessary to bend or twist the
boot lid back to its correct alignment. When the
boot lid opening is at fault it must be carefully X
checked, and it can only be realigned by the use
of hydraulic equipment.
14.4 Major repair techniques
In major repair work the method of repair is
to analyse the crash, establish the order in which
the collision damage occurred, and reverse the
order when correcting the damage. Distortion of
the vehicles underframe in the case of mono constructed
vehicles, or of the chassis in composite
constructed vehicles, must be rectified first before
any other part of the repair is attempted. Any
vehicle body under major repair will never hold
its correct alignment unless underframe damage
has been completely repaired first. This essential
stage in the repair of the vehicle is carried out
by first inspecting the damage and checking its
alignment by one of the recognized methods to
locate the exact position and extent of the damage.
Correction is carried out by using alignment and
repair equipment in conjunction with hydraulic
pulling and pushing equipment to realign any
underframe members which do not align with the
specified locating points (see Figure 14.78). Any
members which are beyond economical repair can
be cut out and replaced with new sections by
using a combination of power tools and MIG
welding equipment. The use of this hydraulic
equipment together with the alignment and repair
system will ensure precise accuracy of the complete
underbody.
Figure 14.78 Pulling equipment being used to
realign underframe members (Car-O-Liner (UK) Ltd)
The next stage of the repair is the realigning
and reshaping of the body shell structure, and
is normally known as roughing out the damage.
After alignment checks have been made, hydraulic
equipment is used to push and pull the body
shell back to its correct shape (Figure 14.79). It is
advisable to rough out all damaged sections, even
though some of these may eventually need replacing
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with new panels. The reason for this is that the
successful fitting of a replacement section will
depend on the correct alignment of the surrounding
areas, which can best be achieved by restoring
them to as near the true shape as possible before
the removal or cutting away of the sections beyond
repair. It has been found that the use of multiple
hydraulic pulling equipment used simultaneously
is the most effective method when dealing with
the majority of major collision work, together
with standard hydraulic body jack equipment as a
450 Repair of Vehicle Bodies
secondary pushing/pulling facility to aid the repair of
the damage. The main advantage is the fact that the
pulling is done externally from any angle while the
car is anchored securely. In cases where there is
a tear in the damaged section, this must be welded
up before any pulling or pushing is attempted,
otherwise the tear will hinder the rectification and
possibly become greater on the application of force.
An important factor is that heat can be used to
relieve stress in correcting damaged sections that
have been badly creased or buckled as a result of
impact. In this case the stress resulting from the
buckle helps to retain the metal in its damaged
state, and even after it has been restored to its
correct shape by the application of pressure from
hydraulic equipment, the section will tend to return
to its damaged position if pressure is released.
Therefore it is of considerable importance that
before the pressure is taken off, these buckles or
creases are hammered out with the use of heat and
hand tools. When using heat for relieving stresses,
it is important not to overheat the section beyond
dull red, and wherever possible never to heat any
point more than once as excess or repeated heating
on one spot causes surface oxidation and annealing,
both of which weaken the member or panel
area. Heat can only be used on low-carbon steel
panels and not on high-strength steels, because
heat weakens the latter by disturbing the heat
treatment which originally strengthened them. This
is particularly so in the case of frame members,
where part of the strength of the member is derived
from internal stresses set up during the forming
operations in the manufacturing processes.
When the roughing out stage is complete and any
major body misalignment has been corrected, then
the panel assemblies which are beyond repair must
be cut out in such a way that the remaining connecting
flanges are left intact. These are then straightened
with the use of hand tools to facilitate the
locating of the new panel section, which after positioning
must be checked for alignment with its surrounding
panels. When the alignment of the new
piece is correct it is welded into position; since the
vehicle is still in the repair equipment, correct alignment
is maintained (Figure 14.80), check that all
doors, the bonnet and the boot lid fit and operate in
the appropriate body shell openings. Minor damage
such as small dints and scrapes in the original panels
should now be repaired using hand tools and the
conventional techniques of planishing or filling.
Figure 14.79 Realignment of the body shell using
simultaneous push and pull hydraulic equipment
(Kroll (UK) Ltd)
Figure 14.80 Welding in new panel sections while
vehicle remains located on alignment and repair bench
(Dataliner, Geotronics Ltd)
On completion of all repairs to structural and
panel damage, the vehicle can be removed from the
alignment and repair system. All dismantled
mechanical and body trim parts can be reassembled,
including any necessary replacements to windscreen,
rear window and door windows. It is imperative that
after repairing all major accident work the vehicles
steering geometry is checked with optical alignment
equipment and a road test carried out to assess its
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roadworthiness and handling capabilities. When the
Major accident damage 451
repairer is satisfied with the vehicles performance
and that all repairs have been completed, the vehicle
will need refinishing to return it to its original factory
finished condition (Figures 14.8114.88).
Although every vehicle receiving major collision
damage must be individually treated, the following
is a basic approach to repair procedure:
1 Inspect and check underframe or chassis for
alignment using conventional equipment.
2 Rectify any misalignment of underframe or
chassis using hydraulic pulling and pushing
equipment, hydraulic body jack, and alignment
and repair system.
Figure 14.81 Vehicle showing front-end damage
being lifted to be positioned on the jig (Motor
Insurance Repair Research Centre)
Figure 14.82 Vehicle on jig being pulled before
cutting out damaged sections (Motor Insurance
Repair Research Centre)
Figure 14.83 Vehicle on jig showing damaged
sections removed (Motor Insurance Repair
Research Centre)
Figure 14.84 New inner wing and chassis section
ready to be welded in place (Motor Insurance Repair
Research Centre)
3 Realign body shell, correcting damage with
a combination of pulling equipment and body
jack, and the use of heat and hand tools (not
HSS). Also cut out and weld in any replaced
buckled panels and reinforcing members which
are beyond repair.
4 Repair doors, fit glass, and body trim to doors
and check for ease of operation and alignment
of the door in the opening in the body shell.
Also check alignment of bonnet and boot lid
and ease of operation.
5 Smooth and finalize minor damage to body
panels with hand tools.
6 Replace all mechanical, trim and body parts.
452 Repair of Vehicle Bodies
Direct pulling
This is achieved by using systems which are
designed around a base beam, sometimes mounted
on castors for easy movement, with an upright beam
pivoted at one end. A hydraulic push ram is mounted
across the angle between the two beams. When the
ram is extended, the upright beam is pushed in an arc
backwards, thus putting tension on to the chain
attached to the damage. This produces a direct pull
between the repair and the beam (Figure 14.89).
Vector pulling
This is achieved by attaching a chain to the damaged
area, then passing it over a hydraulic ram set
as near to 45 degrees as possible, and anchoring
it to either a rack, a tie-down system or a special
clamp. Pressure is applied to the chain by extending
the ram; this puts tension in the chain, which in turn
Figure 14.86 Front panel positioned and welded in
place (Motor Insurance Repair Research Centre)
Figure 14.87 Bonnet and wings positioned (Motor
Insurance Repair Research Centre)
Figure 14.88 Panel repairs complete (Motor
Insurance Repair Research Centre)
Figure 14.85 New inner wing section welded in place
(Motor Insurance Repair Research Centre)
7 Replace windscreen and rear windows if
necessary.
8 Make an optical check on the vehicles steering
geometry.
9 Road test the vehicle.
10 Refinish to original factory condition.
11 Valet cars interior and exterior.
12 Final bodyshop check for quality control of
completed work, prior to returning vehicle to
customer.
