Chery QQ6 (S21) / S12LHD. Manual — part 149

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strict, so the car doors are difficult to maintain and the quality requirements are fairly high, and only the
service personnel understand the structure of the car doors thoroughly and are qualified for the maintaining
operations.

1. Vehicle Door Structure

Generally speaking, the vehicle doors consist of outside plates, inside plates, window frames, glass guide

rails, hinges, locks and window accessories and so on. The inside door plates are equiped with accessories
including glass lifter, locks and so on. To secure the assembly, some parts of the inside door plates need to be
fortrified. To increase safety level, the inner parts of the outside plates are usually equipped with impact bars. The
outside plates and inside plates are connected by flanging, adhesion, seam welding and so on. Depending on
different bearing capabilities, the outside plates should be light and the inside plates should have higher rigidity
and be able to stand stronger impact.

The BIW vehicle door assemblies have relatively fewer components, and usually consist of inside plates,

outside plates, glass guide rails, window frame reinforcing plates, lock mounting plates, hinges reinforcing plates,
impact bar assemblies and so on; The figure below is a typical structure drawing of a vehicle door.

2. Door panel Maintenance Process

Generally speaking, the basic maintenance methods for car doors and hoods are the same as

those for ordinary plate work, and the following steps apply to both of them:

（1） Primary tests. The positions of the door panels as related to other assemblies of the

vehicle body as well as the dimensions of their tolerance clearances should be tested;

Front glass guide rail

Rear view mirror mounting plate

Upper door glass guide rail

Rear glass guide rail

Upper

hinge

mounting

plate

Weather strip guide rail

Outside

plate

window

frame stiffening plate

Inside plate window frame
stiffening plate

Door lock mounting plate

Inside plate back

Rear impact bar connecting
plate

Impact bar

Front impact bar connecting
plate

Lower

hinge

mounting

plate

Position

limitator

mounting plate

Outside door plate

Inside plate front

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（2） Clean the vehicle doors. Use fresh water or detergent to clean the dirt and greasy spots

on the door panels, and let them thoroughly dry for tests.

（3） Maintenance appraisal. Appraise the scope and degree of damage to the door panels by

testing and decide the maintenance methods.

（4） Clear the old paint. Before cleaning or maintenance, get rid of the old paint according to

the actual situation, especially when there exists obvious rust, cracks or dents; The paint
can be got rid of in manual, heating, mechanic or chemical metchod(s).

漆面

焊矩

铲刀

（5） Tests after the removal, including the measurements of the geometric dimensions

between various plate work pieces, tests of specific damage spots of various plate work
pieces, recognition of damage types, analyses of damage causes and choices of
maintenance schemes.

3. Main Contents of Door Panel Maintenance

Generally speaking, the causes of door panel damages are related to the following 4 aspects:

structure design defects, manufacturing defects, chemical erosion, and physical damage. And the
most common damage causes can be classified as the following types:

1 ． Abrasion: The surfaces of plate work pieces may contact each other and relative

movements will take place and cause surface friction, which will lead to abrasion. For example, the
long time friction between the hinge hole and the shaft of the vehicle door hinge will increase their
tolerance clearance and cause to vehicle doors to drop.

2． Erosion: This is generally due to the oxidation caused by the mud deposit and dirt; or the

rust caused by lack of anti-erosion processing after welding; or erosion caused by chemicals. This
type of damage usually occurs between the plate work pieces, in overlapped parts of spot-welded
pieces, and at other similar places.

Scraper

Painted
surface

Welding torch

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3． Cracks or breaks: The metal plates may develop fatigue under repeated inner/outer stress

where the stress concentrates and the structure is the weakest, causing cracks and even breaks.

4． Dents or wrinkles: Dents develop because the door panel is subjected to bumping or

pressing, leading to elastic or plastic deformations.

5． Bends or twists: They are mainly caused by too much load the door panel receives in use or

the plastic deformation due to bumps.

4. Basic Methods for Door Panel Maintenance

The basic maintenance methods for the above door panel damage types include dent

reconditioning, flame correction, welding, repairing and mending, wrinkle spreading and so on.

4.1. Reconditioning of Dents

For convex-concave damages in the outside door panels, if they are indirectly caused by

structural pieces or reinforcers, the structural pieces should be corrected first, and then the outside
panel breaks or dents are to be corrected. If the backs of the metal panels are accessible, hand
hammers and underlay irons or spoon-shaped irons, tommy bars, flat punches and so on can be used
for primary repairs. For enclosed metal panels or parts that are difficult to access from the backs,
other tools can be used for repairing, such as slide hammers and pointed hammers.

Here are some common ways of dent reconditioning:

(1) Repair the dents with underlay irons and hand hammers: the commonest practice is to beat

the damaged metal panels with underlay irons and hand hammers. Both sides of the metal panel to
be repaired must be accessible to the hand-held underlay iron and there are two ways of using the
underlay iron as the supporting piece for the hand hammer:

① Beat with a hammer from above the underlay rion. This approach is suitable for correcting

smaller and shallower dent or breaks.

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When beating with a hammer from above the underlay rion, the hand-held underlay iron

should be placed against the back of the metal panels, and then beat the convex part. The beating of
hand hammer can make the metal panel contract and finally smooth the metal panel.

② Beat with a hand hammer from other parts than from directly above the underlay iron.

The underlay iron is placed against the lowest part of the dent, and then the higher parts near the
dent are beaten with a hand hammer.

Generally, when trying to repair the dent with a hand hammer and an underlay iron, the convex

side is beaten with the hand hammer and the concave side is pressed against the underlay iron. First
do brief correction by beating the damaged part with a wooden hammer, and then do finer repairing
with an iron hammer. For a larger area of dent, the underlay iron should be placed against the place
where the dent is shallower, and the hand hammer should beat the higher parts. Besides, the wooden
hammer and the iron one should be used alternatively according to the actual situation.

(2) Repair the dent with a shaping spoon or tommy bar. Shaping spoons and tommy bars are

commonly used tools for door panel maintenance, and they are customized according the
characteristics of the vehicle body. They can reach the limited space between door panels to push up
the dent. This method is suitable for the narrow room between the door panels where it is
inaccessible for the underlay iron or the hammer, and the shaping spoon can act as a underlay iron
to distribute the impact of the hammer over a larger area.

(3) Restore the dent with a dent smoother. The dent smoother is applied to the inner side of the

metal panel and it is used for the dents that are hardly accessible to other tools and it is usually
operated in the following two ways: