The hood, trunk lid, doors and front fenders are bolt-on and can be replaced. When installing body elements, it is necessary to maintain a uniform gap along the line of their interface, because otherwise, door knocking occurs or increased wind resistance occurs during movement. The gap must have the same value along the perimeter of the fit of the body elements. Deviations of the gap width are allowed no more than 1 mm.
Attention! If any electrical work is to be carried out as part of the body work, the negative cable must be disconnected (-) battery. To do this, you need to familiarize yourself with the materials of the Section Replacing the battery. Even disconnecting an electrical wire from any outlet should be considered as work on electrical equipment.
Note. Many lids and claddings are fastened with clips. Damaged or missing clamps must be replaced. Removal and installation of expanding and retaining clips, refer to the appropriate section.
Safety measures during body work
If it is necessary to weld the body, this must be done using spot welding. Only in the case when there is no place for installing welding tongs, welding in a shielding gas environment can be used.
The battery must be completely disconnected for the duration of welding or any other work associated with the formation of sparks (disconnect the positive and negative cables and insulate the battery poles with duct tape).
Attention! If the radio has a code, then the latter is erased when the battery is disconnected. The radio can only be switched on after entering the correct code, by a MERCEDES workshop or by the radio manufacturer. Therefore, before disconnecting the battery, it is necessary to find out the code of the radio.
Note. During body work, for example, hammer blows cause strong shaking of the vehicle. Therefore, it is imperative to turn off the ignition. Otherwise, the airbag may deploy. Familiarize yourself with the safety measures when handling the airbag, refer to Section Safety precautions when working on the airbag.
Models with air conditioner: Welding and soldering or soldering of air conditioner components filled with refrigerant is not allowed. This also applies to the production of welding and soldering of vehicle elements, if this can lead to heating of the air conditioning elements.
Security measures
Do not open the cooling circuit of the air conditioner, as refrigerant, getting on the skin, can cause frostbite.
In case of accidental skin contact with refrigerant, rinse the affected area with cold water for at least 15 minutes. The refrigerant evaporates at outside temperature. The refrigerant is colorless, odorless and heavier than air. Since the presence of refrigerant is not felt, there is a danger of suffocation in the area of the underbody of the vehicle and in the inspection ditch.
Drying of the paintwork: When painting during the repair process, drying in ovens should not be carried out at temperatures above + 70°C. Otherwise, the vehicle electronics may be damaged. In addition, the pressure in the air conditioner may increase, which will lead to the destruction of the system.
Removal of PVC protective coating under the car: To protect against corrosion, a PVC protective coating is applied to the bottom of the car and wheel arches. The coating should be removed with a rotating wire brush or a hair dryer at a temperature not exceeding +180°C, followed by removal with a spatula.
Warning! Due to the combustion or heating of PVC above +180°C, acids are formed that contribute to corrosion. In addition, unhealthy vapors are formed.
When repairing the body, spot welding should be used. Only if it is impossible to bring electrodes to the place of welding, welding in an inert gas environment should be used. Since some body parts are galvanized, the following safety measures must be taken:
When carrying out welding work or any other work involving the formation of sparks, be sure to disconnect the battery (positive and negative cables) and carefully insulate both terminals (-) And (+). When working near the battery, it must be removed.
Attention! Attention! When the battery is removed, the data from the electronic memory units, in particular, the radio code, are erased. Without a code, the radio can only be switched on by its manufacturer or a Mercedes-Benz workshop.
Notes:
- When welding galvanized sheets, toxic zinc oxide is formed. Therefore, it is necessary to ensure good ventilation of the workplace.
- Increase welding current by 10%, maximum 30%.
- Use hard copper electrodes with high heat resistance (above +400°C).
- Clean the electrodes frequently and grind them down to a contact surface diameter of 4 mm.
- Increase the pressure on the electrode.
- Increase welding time. The time is correct if the welding points are placed without spatter.
- Parts of the air conditioner filled with refrigerant must not be welded and soldered with either soft or hard solder. This also applies to situations where there is a risk of heating of air conditioner components when welding or soldering other structural components.
Additionally
Do not open the cooling circuit of the air conditioner, as refrigerant can cause frostbite if it comes into contact with the skin.
When applying a paint coating in a drying oven, the vehicle must not be heated to temperatures above + 80°C. Otherwise, the vehicle electronics may be damaged. In addition, the pressure in the air conditioner increases, which can lead to the destruction of the system.
The protective coating of the bottom of the car made of PVC is removed with a rotating steel brush or hot air with a temperature of up to +180°C using a spatula. When the PVC coating is heated to temperatures above 180°C, a chemical reaction occurs and hydrochloric acid is formed, which contributes to active corrosion, in addition, harmful vapors are formed.