41 00... Straightening Aluminum Components

1.0 Recommended tools

• Use only those tools specially intended for aluminum repairs.
• Do not use any tools that have already been used for steel repairs (contact corrosion).
• Do not use any sharp-edged tools (notch effect).

2.0 Straightening outer skin

• "Cold" straightening: Press dents out from their center and smooth in an outwards direction with gentle taps.

  In the case of small, soft dents (hail and parking damage), this is also possible without damaging the paintwork.

• "Hot" straightening: Heat dents in their central point only with a gas flame or hot air blower. Then quench the material with a wet cloth. Heating can only be detected by a curvature of the material. The color of the material does not change.
• In the case of damaged areas which are only accessible from one side, stud welding can be used. The aluminum bolt welded on in the center of the damaged area is beaten out with a hammer until the dent is eliminated. The bolt is then ground off.
• Avoid notching and cracking.
• Avoid hardening and overstretching.
• Avoid heating and excess temperature the outer skin over large areas.

3.0 Straightening structure

• Reshaping or heating extruded profiles and cast parts is not permitted! 

  Failure to comply with this requirement would have the following results:

  During reshaping, weld seams tear (E52) or bonded connections in the surrounding area.

  In the case of reshaping, the material loses up to 40 % of its original strength.

  In the case of heating, the material loses up to 40 % of its original strength.

  The adhesive is destroyed at temperatures ≥120 °C.

  Extruded profiles and cast parts which show visible or measurable signs of deformation must be replaced.

  Perform the check for deformation with the aid of the straightening system.

  For optical testing, strip adjoining components in cases of doubt.

  Extruded profiles are used in the E52 as engine supports, door posts, side members, etc.

  Extruded profiles are used in the E60, E61, E63, E64 as engine supports.

  F12During E60, E61, E63, E64, E70, E71, E72, F01, F02, F04, F07, F10, F11, F12 cast parts are inserted as spring strut dome.

• Exceptions on the E60, E61, E63, E64:

  Carrier support and bulkhead may be straightened if they do not have any cracks, sharp-edged damage or holes. After repair work, check parts again for cracks.

  Examine adjoining adhesive flanges for peeling off. If necessary, seal and preserve with SEALANT .

  Observe the frame reference dimension for the carrier support.

  Any repairs to the bulkhead if cracked outside the approved scope of repair work are only permitted after consultation with and approval by BMW.

• Reshaping of extruded profiles and cast parts may only be used to achieve optimum joining of connection faces (e.g. when bulkhead is damaged). Reshaped parts must be replaced.
• Repairs which affect the attachment points of mechanical assemblies and chassis/suspension components must be carried out on the straightening bench. Use the vehicle-specific set of attachments set or vehicle-specific data sheet.

  Straightening attachment supports and data sheets are also available for the top section, e.g.: door posts, soft top mounts, cowl panel, tailgate hinges, etc.

• Check windscreen and rear window apertures for curvature by inserting the original glass.
• Take the gap dimensions for doors, engine compartment lid and tailgate from the vehicle-specific gap dimension diagram.