Chery Tiggo T11 LHD. Manual — part 12

Chery T11 Service Manual

Body and Accessories

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3) Crack or rupture. Due to the repeated action of stress on metal plates, places with

stress concentration and weak structural point tend to be fatigue, hence be resulted in
crack, even rupture in the worst case.

4) Sunkin or folding. Sunkin damage is of elastic or plastic deformation resulted from

collision or extruding between surfaces of door and cover.

5) Bend or distortion. The damage is mainly of plastic deformation to the door and cover

due to overload in using or in case of collision.

Ⅱ Basic Method for the Service of Door and Cover

Aimed at the above types of damages, techniques used for the service of door and cover mainly
include sunkin truing, flame correction, welding, mending, and fold removing.

1. Sunken Truing

For sunken and protruding damage on the external plate of door and cover, if it is of indirect
damage due to the damage of structural parts or reinforced bar, structural parts shall be corrected
firstly, then have the fold of external plate or sunken be corrected. If the rear side of metal plate
can be contacted, hand hammer, sizing block or key block, tommy bar, flat punching can be used
for the initial repair. For enclosed metal plate or places hardly can be contacted, it can be repaired
by inertia hammer, pointed hammer and so on.

The following methods for sunken truing are often used:

(1) Sunken truing by sizing block or hand hammer. Sizing block together with hand harmmer to
hammer the metal plate is a method often used. Both sides of the truing metal work shall be
accessable by portable sizing block. Sizing block can be used as support for the hand hammer in 2
ways:

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① Hammering on sizing block by hand. This method is suitable for the truing of small,

shallow sunken and fold. When hammering on sizing block by hand, the sizing block shall be
placed on the back of the metal plate and held by hand tightly, and start to hammer from the
protruding in front. Hammering on the protruding will cause the metal plate to shrink and
gradually be levelled.

② Hammering on places outside the sizing block by hand. This method is to place the sizing

block at the lowest point of sunken metal plate, and hammer on the adjacent high point by hand.

Normally when truing the sunken area by hammer and sizing block, the protruding side of metal
plate will be hammered, and the other side is padded by sizing block. First hammered by wooden
hammer for a rough shaping, then conduct truing by iron hammer (See Fig 7). For large area of
sunken, sizing block shall be placed at the place with slamp sunken, and hammered on places
protruding high. Wooden hammer and iron hammer shall be used in turn according to the actual
situation.

(2) Repair the sunken by shaping key or tommy bar. Shaping key and tommy bar are manual tools
often adopted for the repairing of door and cover too, which can be custom made according to the
feature of body. These tools can be extended into limited space in the interlayer of door and cover
to lift the sunken area. This method is suitable for sunken area inside a narrow interlayer of door
and cover where sizing block and hammer are not accessable. Shaping key can also be used as
sizing block to radiate the striking force in a large area.

(3) Eliminate sunken area by sunken puller. Sunken puller is applied to the inner side of the metal
plate to repair shallow sunken area which hardly accessable by other tools. There are two
operation methods often adopted by sunken puller:

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One is called hole-drilling method. Namely to drill a hole at the sunken place by portable drill,
then insert a pull rod with thread or hook at the top into the borehole, to draw back the sunken area
slowly by moving the inertia hammer on the metal pull rod and repeated bumping on the handle.
More than one small hole can be drilled in case of necessary. When the sunken area is levelled, fill
these holes by soldering, and have it polished.

Another way is of electrode welding. Namely to weld a pin or mat to sunken area by special spot
welding machine, then install a puller on the pin or mat to pull the sunken plate outward till it is
levelled. More than one pin or flat mat can be welded based on the actual situation to pull out the
sunken area gradually. Finally, break the pin or mat and have the scar polished by grinder. Drilling
on metal plate can be avoided in this method, potential erosion is eliminated, hence it is widely
adopted.

2. Restoration of Stretched Part

The sunken area of stricken metal plate is often stretched out. Correct operation during the
repairing sometime still can’t ensure the complete restoration of stretched part, therefore, heating
shrinkage is often needed to achieve perfect truing.

(1) Heating position and flame energy. The effect of flame correction is relied on the heating
position and flame energy, different heating position will result in different effect for the
correction. The heating position shall be at the place with the maximum deformation and the
longest stretch, namely the outside of the bending deformation of material. Different flame energy
will also result in different effect for the correction. Higher energy, faster heating, and
concentrated heat will result in sdtronger shrinkage. For mild steel plate, heating up to cherry red
(600C~ 800C) will be enough.

(2) Way of heating. Heating methods often used for flame correction in body service include:

① Spot heating, namely that the heating area is at a spot within a specific diameter, which

normally at 1530mm. One or more spots can be heated during the correction according to the
deformation of metal plate. Spots will be distributed in cinquefoil, which is often adopted to
shrink protruding located in the middle of faceplate.

②Triangle heating, namely that the heating area is of a triangle, which is often adopted for

strip material as well as the correction of edge deformation.

Inertia Hammer

Inertia Hammer

Handle

Handle

Flat Mat

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Triangle heating

(3) Cold shrinkage method. When the metal plate is removed from flame, proper cooling method
shall be adopted based on the stretching degree of metal plate as different cooling method has
different shrinkage.

① Natural cooling. Namely to cool it down naturally in ambient environment. It is suitable

for deformation with small shrinkage.

② Water cooling. To cool down rapidly by covering the heating area with wet cotton cloth,

the shrinkage of steel plate is much higher than natural cooling, however the steel may be
embrittled.

③ Natural cooling together with hammering. It is often used together with hammer and sizing

block by swift hammering on the surrounding of heating area to enhance compressive stress and to
increase the shrinkage till the place is levelled. Wooden hammer is perferred for the hammering.
No excessive striking force is allowed so as to avoid that the metal plate is stretched again.

3. Mend by Replacing the Damaged Part

When the metal plate of door and cover is partially eroded or damaged to the extent which can’t
be repaired, it shall be mended by replacing the damaged part with updated part through welding.

The mend can be divided into sticking mend and replacing mend.

The technique procedure for replacing mend is as follow:

(1)Checkup the damage to define the scope of mend.

(2) Work out paper sample according to the defined scope of mend.

(3) Prepare the material from metal plate according to the paper sample with proper margin for
machining.

(4) Select the right processing method to allow the replacing part have identical surface shape
with the part to be cut off.

(5) Clamp the replacing part to original place, mark the outline of the part to be cut off, cut it off
by gas cutting or ordinal cut according to the actual situation, and align the joint of repalcing

Spot heating

Stretched area

heating

Stretched area

heating

Heating position

Wave edge