Head Protection System - Airbag Replacement
GROUP 72Safety Restraint Systems
Bulletin Number
72 01 00
Woodcliff Lake, NJ
April 2000
Service Engineering
SUBJECT:
Front HPS (Head Protection System) Airbag Replacement on E38 Vehicles
MODEL:
E38, 7 series produced from 5/97 up to 9/99
Situation:
In September of 1999, a new type of front Head Protection System airbags were introduced into series production. Only the new type HPS airbags (with inert gas generators) are available from the BMW Parts Distribution Centers for replacement purposes (e.g. after deployment caused by an accident). In case the new style Head Protection System airbag is retrofitted into a E38 vehicle manufactured prior to 09/99, a certain modification to the airbag mounting points in the vehicle, and to the firing circuit harness is required. The table provides part numbers for the new HPS airbags:
For a detailed installation instruction refer to the BMW Technical Information System (TIS) Repair Manual RA 72 12 020.
The procedure included in this Service Information Bulletin provides only additional information and installation hints which are not found in the Repair Manual.
Procedure:
Major difference between the new and the old type of front Head Protection System airbag:
(1) After 9/99 production, new type (long metal gas generator).
(2) Prior to 9/99 production, old type (black plastic gas generator)
The new type HPS airbag gas generator installation position was changed. The generator is located on the bulkhead cross-member, by the holder for the instrument cluster.
In order to replace the front HPS airbag, remove dashboard and headliner (follow the repair manual RA 72 12 020).
To modify vehicle installation points:
1. Trim bulkhead sound insulation in the areas indicated on the illustration
2. Position the HPS airbag gas generator on the bulkhead as shown on the illustration. The retaining lugs of the generator must rest flat on the edge of the bulkhead cross-member without any interference from the sound insulation.
3. Mark the position of retaining lugs on the bulkhead. The distance (A) from the edge of instrument cluster holder to the center of bore hole of retaining lugs on HPS gas generator should be equal to 21 mm +/- 1 mm.
4. Drill two holes in the bulkhead (in the marked positions) using a 6.5 mm drill bit. Deburr bores, protect against rust, and remove (vacuum) metal chips which were generated by drilling.
The new HPS gas generator is secured to the bulkhead cross-member by means of two steel rivet-nuts and two M5 screws. BMW Service Engineering recommends using:
-- MAC Tools Nutsert Installation Kit TSN6S, and
-- Expander series steel rivet-nut ESM5-100BX (thread size 5 mm x 0.8, drill hole 6.5 mm).
5. Install two 6.5 mm rivet-nuts into the holes in the bulkhead cross member (refer to the operating instruction available with the rivet gun kit). Place the HPS head generator in the mounting position, and secure it to the bulkhead by using two hex head screws 5 mm x 16 mm (0.8 pitch), with two 5 mm flat washers.
To modify the ignition circuit wiring harness:
6. Remove the short (about 12") intermediate harness (between generator and vehicle ignition harness connector) from the old type HPS generator head. The round orange connector (vehicle harness side) is going to be reused in the modified harness.
7. At approximately 7" from the round orange connector (1), cut the pair of wires and strip off the insulation at the ends.
IMPORTANT:
The cuts must be slightly offset, so the crimping connectors will not be immediately adjacent to each other.
8. Use the "Airbag Repair Cable" PN 61 12 8 386 369. At approximately 7" from the yellow connector (2), cut the pair of wires and strip off the insulation at the ends.
9. Connect the two parts of the modified harness by using crimping connectors (PN 61 13 8 353 746), and shrink tube insulations (PN 61 13 1 379 833) (# 3 on illustration S72 00 U07).
IMPORTANT:
Pin assignment in the modified harness is not relevant.
For a detailed wire repair procedure for airbag ignition circuits, refer to Service Information Bulletin 61 02 00 (April 2000).
Attach the yellow connector (1) to the HPS generator. Route the modified ignition circuit harness as shown on the illustration, and connect it to the vehicle harness.
IMPORTANT:
Make sure there is no interference between the yellow HPS connector and the sound insulation on the bulkhead.
Trim the sound insulation of the dashboard, according to the detailed instruction provided in the RA 72 12 020.
Parts Information:
Warranty Information: For information only.