BMW X3 Service & Repair Manual: Welding steel components
IMPORTANT: Comply with the following topics from "Body, General": Safety
regulations .
Handling electrical system, electronics, airbags and restraint systems .
1. General information
2. Work materials
- MAG welding:
- Steel welder (see WORKSHOP EQUIPMENT).
- Steel welding wire - G3SI1 (SG2) or alternatively G4SI1 (SG3)
- Welding mask
- Gas bottle containing inert gas (82 % argon, 18 % CO2)
- Resistance pressure spot welding:
- Spot-welding apparatus (see WORKSHOP EQUIPMENT).
- Safety goggles
3. Preparations for MAG and spot-welding
-
Remove the paint coating in an area of approx. 30 mm around the weld seam or spot.
- The zinc layer underneath must be removed during the MAG welding method.
- It is not necessary to remove the zinc layer underneath during spot-welding.
- Remove the paint coating on the reverse side of the weld seam or spot.
-
Contaminants will otherwise enter the weld pool via the root of the weld seam.
- An insufficient electron flow prevents an optimum spot-weld joint.
- Coat all metal overlaps and weld spot flanges with welding primer.
- To determine the optimum electrode contact force for spot-welding, carry out spot-weld shear tests
on sample sheet metal.
- In order to keep the electron flow short during MAG welding on the body, you must if possible
attach the ground terminal directly to the component to be welded.
4. Welding
- During MAG welding, the weld gap must be kept as small as possible. The larger the weld gap, the
lower will be the strength of the joint.
- During spot-welding, the sheet metal flanges to be joined must be placed as close together as
possible without gaps.
The larger the gap, the lower will be the strength of the joint.
Minimum distance between welding spots 25 mm.
5. Subsequent treatment of welded connections:
-
When grinding a weld seam, do not grind thin the base material next to the seam.
-
After joining, clean all weld seams and spots with a stainless steel wire brush.
- Remove burnt paint with a stainless steel wire brush.
-
All welded connections sealed off with body sealing compound in original condition must be
primed and sealed off again thoroughly after repairing. Replace damaged or removed anti-
drumming layers.
In the case of a partial replacement piece, a body component is cut at a point described in the repair
instructions.
A reinforcement plate is we ...
Properties of cavity foam:
2-component PU foam, solvent-free.
Excellent flow capacity, enabling complete sealing of cavities.
Good strength, p ...
Other materials:
BMW X3 Service & Repair Manual > Rear axle: Extension
Extension Minimum set: Mechanical tools AM
NOTE:
(Extension (1 item)) discontinued, can only be ordered using complete tool
SI number
01 21 06 (300)
Extension Minimum set: Mechanical tools AM
NOTE: (2 pieces) Pull-out extension for 33 5 040, 33 5 050, 33 5 060.
Storage Location
A18
B18
...