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REPAIR MAINTENANCE OPERATION OF MOTOR VEHICLES
Mercedes-Benz C-Class (from 1993 to 2000, the year of issue)

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Mercedes-Benz C-class
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Corrosion of metal
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Corrosion of metal



Approximately 70% of the car value determined by the state of the body. And it, in turn, depends on whether the vehicle has been in an accident and, above all, on the degree of corrosion damage.

The causes of accelerated corrosion are divided into two groups and are connected:

- Constructive or technological features of specific models;
- From external influences.

The first group includes:

- The occurrence of high stress and vibration of the metal body;
- The existence of "pockets" in the supporting body sections;
- The use of a thin metal sheet (0.7-0.8 mm);
- The use of a metal alloy, which increase the rate of corrosion;
- The presence of corrosion in the form of concentrates, moldings and other decorations.

External influences include:

- Sulfur compounds, carbon dioxide and chloride contained in the environment;
- Saline solutions used to combat icing.

Under our conditions the most impact have various salt solutions, because they lead to the formation of conductive "bridges" between the parts of the body, usually having a different electrical potential. This causes the most destruction bystrotekushy kind of metal - galvanic corrosion. The idea that all cars have a single-wire wiring diagram, and therefore the body of "walk" currents from one user to another.

We will not delve further into the theory, leaving it to those skilled in the field of corrosion and turn to practical matters. These results are based on the use during the examination of the three types of devices, to assess:

- Change the thickness of a "live" metal that is not exposed to corrosion;
- The degree of erosion of the metal on the inside, in other words, the degree of its disintegration or destruction of oxides;
- Thickness of cosmetic layer (paint, putty), which allows you to determine whether the body to repair and try to hide it.

The results of examinations are carried out by experts, the following conclusions:

1. In our region the rate of penetration of corrosion in metal for vehicles with winter operation is - 0.2 mm per year and 0.1 mm per year for the car, who had not seen salt.

2. Especially developed rapidly corroded in areas exposed to body repair, and that very quickly, if the repair was carried out with the use of welding or soldering, as are electrochemical pair of dissimilar metals. To buy a car, especially a foreign car, it is fundamentally important. It's no wonder thrifty Europeans are almost always sell even slightly broken car (though getting insurance) for a pittance - $ 1-2 thousand. How much they then re-sell in our markets, the reader probably knows himself. But if you happen to find a hidden defect before making a purchase, be aware that the real cost of such vehicles by 25-50% lower than the unbeaten. We must not forget that sooner or later you will sell a car, and without buying expensive experts are now making only a very naive people.

3. The fastest in the process of corrosion in vehicles operated in the winter and stored in the garage, especially warm, without dissolving salt with running water. We emphasize not flushing, namely dissolution. Very wrong are those who believe that strong jet washing out the bottom part of the car, they are doing a good deed. The salts dissolve easily and without strong pressure, but the protective coating from the powerful jet rather quickly "unstuck" from the metal sag, creating an illusion of protection. The generated between the metal and sagging putty cavities corrosion develops much faster than in the open metal.

It is not recommended to wash the car with hot water, as because of the different thermal expansion of warming up in the first place the protective cover "slide" to the metal, forming a negative effect.

Wrong those who believe that the protective coating is thicker, the better. All just the opposite. The main thing that was not in the coating breaks, but because it must be updated regularly.

In conclusion - practical advice. Of the two cars is better than one that "younger", and the one on which the process of destruction of the metal does not penetrate to a depth of 0.4-0.5 mm. In this case, no treatment is impossible to prevent the formation of holes and a half or two years. Conversely, even an old car, which has since the beginning of operation of a reliable protection, will last for many years. In our conditions, foreign car can be repaired in the engine and chassis, but not economically feasible to repair badly decayed body.





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