General information and safety precautions (BMW 3 Series E46)

BMW 3 Series cars have a "universal body" design, which uses a floor panel with front and rear side beams (spars) frames that act as carriers for the rest of the car body parts, front and rear suspensions and other mechanical components. Some of the components are particularly vulnerable in accidents and can be removed and repaired or replaced. These include the hood, trunk lid, doors and front fenders. The front and rear windows are glued in place.

This Chapter includes descriptions of only the procedures for general car body maintenance and restoration and repair of body panels that are within the skill level of the average amateur mechanic.

Many of the above mentioned design elements are secured with so-called Torx screws, which require a special screwdriver to unscrew.

If any work is carried out on internal equipment, the following instructions must be observed:

If you are working on the interior equipment and are also working on electrical equipment, be sure to disconnect the negative (-) battery cable. To do this, refer to the instructions in Section Removal and installation the battery. Electrical work should also include disconnecting or unplugging any electrical wire.

• To remove plastic trim and canopies, it is recommended to use a plastic wedge, for example, HAZET 196555-20.
• Any clamps damaged during removal of the trim must be replaced.
• Seats, seat belts and airbags are important safety components. Only the work described in this chapter should be performed. Other work should be performed at a service station.

Safety precautions when performing bodywork

Welding or soldering with soft or hard solders of air conditioning system elements filled with working fluid or if there is a risk of them heating up is not permitted.

Do not open the air conditioner cooling circuit, as liquid coming into contact with the skin may cause frostbite.

If the liquid accidentally gets on your skin, immediately wash the affected area with cold water for at least 15 minutes. The air conditioner fluid is colorless and odorless and is heavier than air. If the coolant leaks, there is a risk of poisoning in the lower part of the car (the presence of liquid is not felt).

The protective coating of the PVC bottom at the welding point must be cleaned with a wire brush and, after heating with hot air to a temperature of +180°C, removed with a spatula.

When PVC coating is heated above +180°C, hydrochloric acid is formed, which has a strong corrosive effect. In addition, vapors are formed that are harmful to human health.

Body parts subject to severe corrosion are galvanized. Do not grind off the zinc coating before welding (removal of the coating is permitted only when soldering with hard solders). In this case, the welding current should be increased by 10%.

When welding galvanized sheets, zinc oxides are formed. Safety measures require good ventilation of the welding area.

When repairing the paintwork, it is permitted to heat the car in a special oven to a temperature no higher than +80°C. Otherwise, there is a risk of damaging electronic devices.



When carrying out welding work on a vehicle with control devices installed, the following must be observed:

Disconnect the negative (-) battery cable with the ignition off. The battery is located in the luggage compartment behind the cover on the right side. In BMW 316i, 318i cars, the battery is located in the engine compartment.

Disconnecting the battery will erase the fault memory of some control units. If necessary, read the fault memory before disconnecting the battery. Refer to Section Troubleshooting. It is advisable to carry out the work in a service station.

Insulate the negative (-) battery terminal to prevent accidental contact.

If welding or other work involving the formation of sparks is carried out near the battery, it is necessary to remove the battery.

When carrying out welding work, the welding machine terminal should be placed as close as possible to the welding site and should be well connected to the body, maximum distance 1 m.

Do not use the vehicle ground connection with the wires secured as a ground connection for the welding machine. If necessary, first disconnect the wires and protect the thread of the ground bolt with a nut.

For vehicles with a navigation system, the navigation magnetic field probe must be recalibrated after welding work has been completed (work of the service station).

Galvanized sheets are installed on the vehicle's structural elements that are particularly exposed to corrosion. The zinc layer should not be removed before welding. It is removed only before brazing with hard solder. The current strength should be increased by 10%.

The operation of lifting and installing the vehicle on stands is associated with danger! Therefore, before carrying out the operation, read the Section Jacking and towing

Body gaps

When installing body parts, it is necessary to observe the established gaps. Otherwise, for example, a grinding sound occurs when closing the door or increased wind noise during movement. The gap must have a constant width along the contour of the parts. The deviation must not exceed 1 mm.

The following condition must be met. The surfaces of adjacent elements must be parallel. An inward shift of 1 mm of elements located closer to the rear of the car in relation to elements located in front of the body is permissible.

For example: The front edge of the rear door may be positioned 1 mm deeper than the rear edge of the front door.

The required clearance values are given in the table.

Designation of body pillars from front to back A, B, C

Section	A-A	B-B	S-S	D-D	HER	F-F	G-G	H-H	I-I	K-K
a =	4.25±0.75	12.8±0.2	13.9±0.2	15.7±2.0	17.2	4.0±0.75	15.0±2.0	8.8 + 3.0/-0	0.0±1.0	1.0±1.0
b =	0±1.0	4.5±1.0	4.0	4.0	0±1.0	0.0±1.0	1.0 + 1.0	1.0 - 1.0		1.0±1.0
c =			25.0±1.0			15.0±2.0	4.5±0.75			5.0 +1.5/-1.0
d =			15.0±2.0				15.0±2.0
1=		Side frame								Channel bar cladding
2=		Front door								Channel
3=		Front glass								Front door