Chery S11 / Chery QQ. Manual - part 100

   

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2.2 Basic method of door maintenance 
In view of above-mentioned damage type, main methods of doors and lids maintenance include 
sinking trim, flame straightening, weld, repair by embedding     

     

2.2.1 Trimming the rough and uneven surface 
You should correct the structural casting first then correct the crease or the hollowness of outside 
door panel if the rough and uneven surface of outside door panel is indirect damage because of 
structural casting damage or stiffening rib damage. You can carry out initial rough repair with 
hammer, beam pad or jimmy  、punch if you can touch the back of metal plank, you can carry out 
repair by means of slip hammer and peen hammer if it is difficult for you to touch the back or the 
metal plank is sealed. 
The common rough and uneven surface trimming methods are introduced as follows: 
(1)Trimming the hollowness with beam pad and hammer. It is the most common method to 
knock the metal plank with hammer and beam pad.The two sides of metal plank which is to be 
trimmed must be applicable to hand holding beam pad.There are two operating methods to take 
the beam pad as supporter for hammer: 
1) Knock on the beam pad with hammer. This method is applicable to the shaping to relative 
small and shallow hollowness and crease. You can knock the protruding from right side. The 
knock will result in metal plank contraction and make the metal plank to be smoothened 
gradually. 
 

 

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2)Not knocking the beam pad with hammer. This method means put the beam pad under the 
lowest place of the hollowness, knock the nearby place with hammer. 
Generally speaking, while trimming the hollowness with hammer and beam pad ,the protruding 
side shall be knocked by the hammer, the other side shall be gasket ,you can make rough shaping 
with wooden hammer then make fine trimming with iron hammer.(see figure 7).In the case of 
hollowness with much bigger area, beam pad shall be put in the more shallow position of the 
hollowness, the hammer shall knock the much higher position of the protruding, iron hammer 
and wooden hammer shall be used alternately accordingly. 
(2)Trim the hollowness with jimmy. jimmy can be self-made according to characteristic of the 
vehicle body, they are handwork tool in common use for door maintenance. can be used to put 
into the limited space of sandwich position of doors and lids ,it can prize open the hollowness, 
this kind of method can be applicable to the hollowness which is not easy for spacer and hammer 
to reach because of the narrow sandwich position of doors and lids, can be also used as the 
spacer to make the hitting power of the hammer spread in much larger area.   
(3)Trim the hollowness with puller. puller can be used to trim the shallow hollowness which is 
difficult for other tools to touch upon, it is can be used inside the metal plank. There are two 
operating methods of puller in common use. 

 

One is boring method. That means to drill a small hole in the hollowness with portable electric 
drill, then insert the withdrawal lever of thread summit or hook summit in the hole, draw the 
hollowness slowly through inertia hammer sliding on the metal withdrawal lever and colliding 
the handle repeatedly. You can drill more holes when necessary, fill and smooth the holes with 
tin-lead bonding after the hollowness is flattened. 
The other method is electrode welding.That means welding the stud nail or spacer on the 
hollowness with special use spot welder, then pull the stud nail or spacer outwards 
withpuller,until the hollowness is flattened. You can weld more nails and spacer accordingly, pull 
the whole hollowness gradually. Finally, polish the welded mark and smooth it with grinder. This 
kind of method avoids making holes in the metal plank; eliminate the potential corrosion of 
metal. 

 

2.2.2 Recovery of stretchable position 
It happens frequently that sheet metal of the hollowness is stretched after being collided. It is not 
sure that the stretchable position can be recovered completely using the correct operational 
method during trimming process ,therefore, it is necessary for you to combine with heating 
contraction method to achieve the goal of trimming. 

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(1) Heating position and flame energy. 
Effectiveness of flame straightening is up to heating position and flame energy, different heating 
position result in different straightening effectiveness. The maximum and longest deformation 
position shall be selected to be the heating position, that is to say the outside of deformation. 
Different flame energy heating results in different straightening ability. The more the flame 
energy, the more the heating speed, the stronger the contraction ability, the more concentrated the 
heating energy , it is ok to heat the low carbon sheet metal to cherry red color  （600 ~800

℃

℃）

. 

(2) Heating mode 
Heating mode which flame straightening method adopt in common use in vehicle body 
maintenance include: 
1) Point -like heating, it means that heating area is the circle-like points within certain diameter 
scope, generally speaking, the diameter is 15-30mm,you can heat one point or more adopting 
quincunx distribution accordingly, it is often applicable to the contraction of protruding in the 
middle of the panel. 
2) Triangle heating, it means that heating area representing triangle shape, it happens frequently 
in the deformation of strip material and panel edge. 
 
 

 

 
 
 
 
 
 
 

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(3) Cooling contraction mode 
You can choose appropriate cooling mode according to stretchable degree of sheet metal after 
evacuation from flame, different cooling mode result in different shrinkage. 
1) Natural cooling contraction. That means natural cooling in the air, which is applicable to 
deformation place with smaller shrinkage. 
2) Water cooling. You can cover the heating area with wet cotton cloth in order to make  
cooling, the shrinkage is deeper in degree than natural cooling ones, but it is easy for the sheet 
metal to be tendering. 
3) Combination natural cooling with hammer knocking, it happens frequently to use hand 
hammer and spacer, knock the surrounding of heating area promptly, enlarge the contraction 
stress and shrinkage, until beaten that position, you’d better use wooden hammer, you’d better 
not put more pressure, so that the sheet metal is not to be stretched once more. 

 

2.2.3 Made-up in digging style and restore 
If local part of door sheet metal piece rot away or the damage is too serious to be repaired, you 
shall dig that damaged part and enchase with relevant substitute materials. It includes pasting 
made-up and digging made-up: 
(1) Check the circumstances of damage make clear the repair scope. 
(2) Make paper sample in accordance with the defined repair scope. 
(3) Scribe lay off on the sheet metal according to paper sample, leave appropriate processing. 
(4)Adopt suitable shaping method, make the enchase piece tally with parts needing to be 
repaired. 
(5)Keep the enchase pieces close to the requested position, draw the bordering line of the parts 
needing to be cut, then cut off the useless part, You can adopt method such as gas cutting、
shear ,bring two things into contact properly. 
(6) Weld the welded seam with oxygen acetylene weld or CO2 blocking welding. Weld properly   

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