Checking Automatic Seat Belt

General notes on checking seat belts:
If it is necessary to check the seat belts due to an accident, you should begin by trying to obtain information on which seats were occupied in the car that was involved in the accident.
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 there are doubts as to the unrestricted functional capability of restraint system components, they must be replaced in the interests of safety!
If it is necessary to replace a seat belt because of an accident, e.g. in the event of a front and/or side impact where the impact absorbers were permanently deformed, replace the complete seat belt (upper strap, lower strap, belt buckle, belt tensioner) including the seatbelt height adjustment and the retaining screws.

The following must also be checked and if necessary replaced:
Seatbelt mountings on the body
Seatbelt mounting on the seat
Seat runners.
Straightening attempts on seat and seat runners are not permitted!

Automatic-reel seat belts must be replaced in case of
1 Activated belt tightener
2 Creases
3 Unravelling
4 Pinches
5 Tears and cuts
6 Traces of melting
7 Traces of wear on casing of buckle latch or on reversing clip.

Also refer to check list for automatic-reel seat belts Inspection List For Automatic Seat Belt
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 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, seat backrest must be set into upright position and both hands held in supporting position close to 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 should lock.

The second activation system provides additional safety and is controlled by inertia mass.

If reel locks when pulling out belt 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!

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:
1 Creases
2 Unravelling
3 Pinches
4 Tears and cuts
5 Traces of melting
6 Traces of wear on casing of buckle latch or on reversing clip.

Checking lower strap (belt tensioner):
To lock, the buckle latch must snap gently into the buckle with an audible click.

When the "Red button" is pressed, the buckle latch must be ejected with spring pressure from the buckle.

If lock cover is missing or damaged, seat belt must be replaced.

Replace triggered belt 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.

Criteria for a triggered seatbelt tensioner:
Mechanical seatbelt tensioner, refer to Repair instructions E 36, 72 11 ... Deactivating mechanical seatbelt tensioner, very low position of seatbelt buckle (comparison with new part).

Pyrotechnical seatbelt tensioner, read fault memory of airbag system (airbag indicator lamp continually lit), very low position of seatbelt buckle (comparisons with new part).

Since the belt tensioners are also triggered under certain conditions when the seat is not occupied, it is possible

If the belt system is definitely not being used
To dispense with replacing the upper strap and the attachments (seatbelt height adjustment, screws) and checking and if necessary replacing the
- Seatbelt mountings on the car body
- Seatbelt mountings on the seat
- Seat runners.