41 00... Straightening Aluminum Parts

1.0 Recommended tools 

• Use only those tools specially intended for aluminium 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 shell 

• "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. This work requires a special tool and a trained worker.

• "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 warpage of the material. The color of the paint does not change.
• In the case of damaged areas which are only accessible from one side, stud welding can be used . The aluminium stud welded on in the center of the damaged area is beaten out with a hammer until the dent is eliminated. The stud is then ground off.
• Avoid notching and cracking.
• Avoid hardening and overstretching.
• Avoid heating and overheating the outer shell over large areas.

3.0 Straightening structure 

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

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

  In the case of reshaping, weld seams (E52) or glued connections (E60, E61, E63, E64) tear 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 (E60, E61, E63, E64).

  Extruded sections 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 sections are used in the E52 as engine carriers, door pillars, frame side members, etc.

  Extruded sections are used in the E60, E61, E63, E64 as engine carriers.

  Cast parts are used in the E60, E61, E63, E64 as spring supports.

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

  Support carrier 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 sealing compound.

  Observe the frame alignment control dimensions for the support carrier.

  Any repairs to the bulkhead if cracked outside the approved repair scopes are only permitted after consultation with and approval by BMW. Should you have any questions, please contact the country-specific Hotline.

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

  Straightening attachment supports and data sheets are also available for the top section, e.g.: door pillars, convertible top mounts, cowl, rear lid hinges, etc.

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