Component Tests and General Diagnostics
Accident Damage And Diagnosis
General notes
- Exact diagnosis of the extent of damage enables proper repair planning.
- All body repairs must be carried out in accordance with the guidelines in this Body Repair Manual.
- The stability and strength properties of the body must be taken into account during body repairs. The body has exactly defined deformation patterns that must not be affected by any repair work.
- For instance, the crumple zones absorb the bulk of the impact energy. If any unprofessional repair techniques or methods are used in these areas then this can pose a fundamental threat to vehicle safety.
Hidden damage
- As well as looking at external indicators like flaked off paint, it is vital to check for hidden body damage or deformation that is not visible from the outside. Large attached parts like bumpers and inner fenders often need to be removed to allow accurate assessment of damage to underlying body parts.
Gap dimensions
refer to: Body and Frame.
Gap dimensions offer another alternative for diagnosis by visual inspection. If any changes or misaligned edges are apparent, then this usually indicates that the dimensions of the affected part are incorrect.
Changes in gap dimension
Obtaining spare parts
The availability of spare parts often determines how easily the body repairs can be carried out. The following procedure is recommended:
- Obtain all the data for the vehicle, including type, vehicle identification number, trim code, engine identification letters, initial registration etc.
- Establish all of the metal parts that need to be renewed.
- Establish all of the attached parts that need to be renewed, including small parts like rivets, clips etc.
Straightening repairs
Straightening repairs are often required to restore the body to its original shape after an accident. This can be done with:
- Alignment jigs
- Universal straightening and measuring jigs
The following points must be followed to ensure that the repairs are carried out professionally and that all the dimensions are correct after the repairs have been carried out.
- Structure:
- The repair sequence depends on the individual repair plan (taking any necessary disassembly work into account).
- Clean the attachment areas.
- Anchor the vehicle free of stress on the relevant system.
- Support the aggregates to take strain off the body.
- Decide on at least three measuring/mounting points that are undamaged and as far apart as possible (for basic adjustment).
- Check the dimensions of the measuring/mounting points.
- Straightening:
- NOTE: Check dimensions and gaps continuously during straightening.
A body is always straightened in the opposite direction to that of the impact. Always carry out straightening repairs with the complete body shell assembled (do not cut out any parts beforehand). Carry out the straightening work in several stages. This prevents the risk of over stretching or of welded joints tearing out. During the individual straightening steps, relieve tension by striking with an aluminium hammer while the part is subjected to a tensile load (in the area of pre-determined folding points, dents, welded joins etc.).
CAUTION: Ultra High Strength steel in the A-Pillar, B-Pillar and cantrail cannot be straightened.
Cutting out body parts
Depending on how the parts are joined/connected, different tools are suitable for cutting/separating body parts.
NOTE:
- All other parts like interior equipment, window glass etc. must be protected against flying sparks.
- Ensure that the milling depth is set correctly to prevent the remaining flange from being weakened.
- Spot-weld mill
Spot-weld mill
- Rod sander
- NOTE: Wear protective clothing. Protect any vulnerable body or glass areas against flying sparks. Remove explosive materials from the vicinity.
Any spot welds that are inaccessible for the spot-weld mill (diameter > 8 mm) should be ground out using a rod sander. The same applies to MIG spot welds or seams.
Rod sander
- NOTE: Underlying metal parts, wiring harnesses, hoses etc. must not be damaged - remove them beforehand if necessary.
Body saws are particularly versatile and are therefore very suitable for making severance cuts on body parts.
Short stroke saw
- Reciprocating saw
- In addition to the short stroke saw, the reciprocating saw can be used. With this, it is possible to make narrow and straight cuts to an exact depth.
Reciprocating saw
