The hood, trunk lid, doors and front fenders are bolted and can be replaced. When installing body elements, it is necessary to maintain a uniform gap along the line of their mating, since otherwise the doors will knock or increased wind resistance will occur during movement. The gap should have the same value along the perimeter of the body elements. Deviations in the width of the gap of no more than 1 mm are allowed.
Attention! If, as part of the bodywork, it is also necessary to carry out any work with electrical equipment, it is necessary to disconnect the negative cable (-) of the 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 terminal should be considered as work with electrical equipment.
Note: Many covers and trims are secured with clips. Damaged or missing clips must be replaced. For removal and installation of expander and locking clips, refer to the appropriate section.
Safety precautions when performing bodywork
If it is necessary to weld the body, this should be done using spot welding. Only if there is no space for installing welding tongs, welding in a protective gas environment can be used.
When carrying out welding or any other work involving the formation of sparks, the battery must be completely disconnected (disconnect the positive and negative cables and insulate the battery terminals with tape).
Attention! If the radio has a code, the code is erased when the battery is disconnected. The radio can only be switched on after entering the correct code, by a Mercedes service station or the manufacturer of the radio. Therefore, before disconnecting the battery, it is necessary to find out the code of the radio.
Note: When performing bodywork, strong vibrations to the vehicle may occur due to, for example, hammer blows. Therefore, it is essential to switch off the ignition. Otherwise, the airbag may deploy. Familiarize yourself with the safety precautions when handling the airbag, refer to Section Safety precautions when working with an airbag.
Models with air conditioning: It is not permitted to weld or solder air conditioning elements filled with refrigerant with soft or hard solders. This also applies to the production of welding and soldering of vehicle elements if this may lead to heating of the air conditioning elements.
Security measures
Do not open the air conditioner cooling circuit, as the refrigerant may come into contact with your skin and cause frostbite.
If the refrigerant accidentally gets on your skin, rinse the affected area with cold water for at least 15 minutes. The refrigerant evaporates at outside temperatures. The refrigerant is colorless and odorless, and is heavier than air. Since the presence of the refrigerant is not felt, there is a risk of suffocation in the area of the bottom of the car and in the inspection ditch.
Drying of paintwork: When carrying out painting work during repairs, drying in ovens should not be carried out at a temperature above + 70°C. Otherwise, the electronic devices of the car may be damaged. In addition, this may increase the pressure in the air conditioner, which will lead to the destruction of the system.
Removing the PVC protective coating from the underbody of the car: To protect against corrosion, a PVC protective coating is applied to the underbody of the car and wheel arches. The coating should be removed with a rotating wire brush or a hair dryer at a temperature of no more than +180°C, followed by removal with a spatula.
Warning! Burning or heating PVC above +180°C produces acids that promote corrosion. In addition, harmful vapors are formed.
When repairing the body, spot welding should be used. Only if electrodes cannot be brought to the welding site, welding in an inert gas environment should be used. Since some body elements are galvanized, the following safety measures must be taken:
When carrying out welding 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 is erased, in particular, the radio receiver code. Without the code, the radio receiver can only be switched on by its manufacturer or a Mercedes-Benz service station.
Notes:
- When welding galvanized sheets, toxic zinc oxide is formed. Therefore, it is necessary to ensure good ventilation of the workplace.
- Increase the welding current by 10, maximum 30%.
- Use solid copper electrodes with high thermal resistance (above +400°C).
- Clean the electrodes more frequently and treat them to a contact surface diameter of 4 mm.
- Increase the pressure on the electrode.
- Increase the welding time. The time is chosen correctly if the welding points are placed without spatter.
- Air conditioner parts filled with refrigerant must not be welded or soldered with either soft or hard solder. This also applies to situations where there is a risk of heating up air conditioner components when welding or soldering other structural elements.
(Original source of information: «MercedesMan»)
Additionally
Do not open the air conditioner cooling circuit, as the refrigerant may cause frostbite if it comes into contact with the skin.
When applying paintwork in a drying oven, do not heat the car to a temperature above + 80°C. Otherwise, the electronic devices of the car 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 car underbody made of PVC is removed with a rotating steel brush or hot air at a temperature of up to +180°C using a spatula. Heating the PVC coating to a temperature above 180°C causes a chemical reaction and the formation of hydrochloric acid, which promotes active corrosion, and also produces harmful vapors.