72 11... Checking automatic safety belt
General considerations when checking seat belts:
The seat belts must be checked after an accident.
For the check, you should start by trying to get information on which seats in the car involved in the accident were occupied. If this is not possible, check all the seat belts in the car and replace them if necessary.
In the event of deformations on the car, you must subject the components of the restraint system affected in this area such as e.g.
- Seat belt
- Seatbelt height adjustment
- Belt buckle tensioner
- Triggering sensors
- etc.
to a function check and a visual inspection.
If you are in any doubt as to the unimpaired functional capability of restraint system components, these components must be replaced in the interests of safety!
If a seat belt has to be replaced following an accident (e.g. in the event of a frontal and/or side impact with permanently deformed impact dampers/deformation elements or cross-members), the complete seat belt must be replaced! The complete seat belt comprises:
- Top belt
- Lower strap
- Seat belt buckle (buckle tensioner)
- Seatbelt height adjustment
- Retaining screws of all components
The following must also be checked and if necessary replaced:
- Seatbelt mountings on the car body
- Seatbelt mountings on the seat
- seat runners.
- Seat structure (frame, etc.)
Alignment tests on the seat and the seat runners are not permitted!
The following explanations and the checklist for the automatic safety belt can provide help.
An unusable seat belt or a seat belt worn in a serious accident should be destroyed immediately after removal to guarantee that it cannot be used again.
Checking automatic reel and seatbelt strap:
The automatic reel has two independent activation systems for seat-belt locking.
The first activation system locks the automatic reel when driving quickly around curves, driving in tight curves, on extreme inclinations (vehicle rolls over) and during sharp braking or impact.
To check, the seat backrest must be placed in the upright position and both hands held in a supporting position close to the steering wheel. The brakes are then applied fully while driving on a dry surface and at a road speed equal to twice that of walking speed.
The seat belt must lock.
The second activation system provides additional safety and is controlled by inertia mass.
If the reel locks when the strap is pulled out suddenly, this system is also OK.
Automatic reel does not require servicing and must not be opened.
Precondition for complete, problem-free retraction of straps:
- the straps must not be twisted!
- the straps must not be damaged!
When placed to one side, the straps of the front seats must retract fully.
With the straps in the rear seat bench, a small remaining loop is acceptable due to increased friction between the strap and the rear seat bench cover if:
- this remaining loop is fully retracted when the strap is reguided.
Belt straps should only be cleaned with a luke-warm soap solution or a commercial laundry detergent.
Belt straps must never be cleaned chemically or dyed.
The automatic reel and strap must be replaced in the event of:
- creases
- unraveling
- pinches
- cracks and tears
- traces of melting
- traces of wear on casing of seat belt tongue or on reversing clip.
Checking lower strap (belt buckle tensioner):
To fasten a seat belt, the tongue should insert easily and with a loud click in the lock.
When the "Red button" is pressed, the tongue must be ejected from the lock under spring pressure.
If the lock cover is missing or damaged, the lower strap must be replaced.
Replace the triggered belt buckle tensioner including the complete seat belt with seatbelt height adjustment and retaining screws and check the
- Seatbelt mountings on the car body
- Seatbelt mountings on the seat
- seat runners.
- Seat structure.
Criteria for a triggered mechanical belt buckle tensioner:
- very low position of seatbelt buckle (comparisons with new part).
Criteria for a triggered pyrotechnical belt buckle tensioner:
- very low position of seatbelt buckle (comparisons with new part).
- Airbag warning lamp permanently lit: read out airbag system fault memory.
The belt buckle tensioners can be triggered under certain circumstances even when the seat is not occupied. If it is definite that the belt system was not used (seat was not occupied), there is no need to replace the
- upper strap
- attachment parts (belt height adjustment, screws)
- seatbelt mountings on the car body
- Seatbelt mountings on the seat
- seat runners.
after a check.