721919 Removing and Installing Front Backrest Frame

WM 721919 Removing and installing front backrest frame

Tools





Technical values






Removing front backrest frame

WARNING

Incorrect handling of airbag units

- Triggering of airbag unit
- System faults can occur

-> Switch off ignition and remove ignition key.
-> A voltage supply (e.g. battery charger) must not be connected to the external power supply/jump-lead starting terminals.
-> Disconnect the battery and insulate the ground strap so that all contact with a ground carrier is avoided.
-> Wait 1 minute after disconnecting the battery.
-> Only pull off connector on the triggering unit after the waiting time has elapsed.
-> Make sure that no foreign objects are located in front of the airbag unit during installation.
-> Replace damaged parts during removal.
-> Always position airbag units so that the blow-out opening faces upwards, e.g. crest on driver's airbag.
-> Do not position anything on the airbag units.
-> If removed for an extended period, the airbag units must be stored in a safe place.
-> Airbag units must not come into contact with grease, oil, detergents, liquids, or similar substances.
-> Do not expose airbag units to temperatures above 90°.
-> Do not remove the short-circuit spring on the plug-in contacts.
-> Ignition and preparations may only be carried out by skilled staff, supervised by a second responsible person.
-> Before disposal, the airbag unit must be rendered harmless by electrical ignition performed in accordance with all precautionary measures, thereby preventing it from being used incorrectly.





Main illustration for removing and installing backrest frame

1. Remove front seat => 720119 Removing and installing front seat - section on "Removing".

Information

- Before the battery is disconnected when removing the front seat, the seat must be moved into top position and the backrest must be tipped back by approx. 45°.

2. Remove backrest cover => 722619 Removing and installing cover for backrest - section on "Removing".
3. Remove inner and outer seat trim => 721619 Removing and installing front seat trim - section on "Removing".

Information

- The number of plugs and wiring harnesses can vary, depending on the front seat equipment.

4. Counter plastic strip -1- of spring core and use a release lever -2- removal tool, universal NR.21 to unclip wire harnesses from the spring core -arrows-.





Unclipping wire harnesses

5. Push back lock on the side airbag connector -arrow A- and remove the connector -arrow B-. Then unlock side airbag connector on the seat frame -arrow C- and push out towards the front -arrow D-.





Releasing connector

6. Unlock ground connector -1- and central connector -2- ( -arrows A- ) and remove both connectors -arrows B-.





Releasing connectors

7. Unscrew inner -3- and outer -4- fastening screws.





Removing backrest frame

8. Using a screwdriver, lever backrest out of the centering bushings at the inner side -arrow- , turn upward and remove from the installation position.





Removing backrest frame

9. Hold backrest in upright position and push outer side of seat cushion inwards -arrow A-. Subsequently pull the wire harnesses upward -arrow B- out of the seat frame.





Removing backrest frame

10. Remove padding for backrest => 741719 Removing and installing padding for backrest - section on "Removing".
11. Remove lumbar support => 723419 Removing and installing lumbar support - section on "Removing".
12. Remove side airbag => 696319 Removing and installing side airbag - section on "Removing".
13. Remove wire harness for backrest => 975619 Removing and installing wire harness for backrest - section on "Removing".

Installing front backrest frame

1. Install wire harness for backrest => 975619 Removing and installing wire harness for backrest - section on "Installing".
2. Install side airbag => 696319 Removing and installing side airbag - section on "Installing".
3. Install lumbar support => 723419 Removing and installing lumbar support - section on "Installing".
4. Install padding for backrest => 741719 Removing and installing padding for backrest - section on "Installing".
5. Engage backrest at inner side for installation of the wire harnesses -arrow-. Make sure that the backrest cannot tilt backward or forward.





Installing backrest frame

6. Push seat cushion away inward -arrows A-.





Installing backrest frame

7. Push wire harnesses down through seat frame -arrows B-.
8. Engage backrest into the centering bushings at outer side -arrows- and screw in both fastening screws but do not tighten.





Securing backrest frame

Information

- Make sure that the plastic sleeve is inserted between the top centering bushing and the backrest.

9. Using a screwdriver, lever inner side of backrest outward -arrow A- , then shift backrest until bores engage on the centering bushings -B-.





Securing backrest frame

10. Screw in both fastening screws on inner side -3- , then tighten fastening screws on both sides -3, 4- => Tightening torque: 34.5 Nm (26 ftlb.).





Securing backrest frame

11. Insert ground connector of side airbag -1- and central connector of backrest -2- into seat wire harness until they engage with an audible click.





Locking connectors

12. Clip airbag connector onto spring core -arrow A- until the lock -B- engages securely.





Locking connector

13. Join airbag connectors -arrow C- until the lock -D- engages securely.





Locking connectors

14. Clip wire harness into spring core -arrows-.





Securing wire harnesses

15. Install inner and outer seat trim => 721619 Removing and installing front seat trim - section on "Installing".
16. Install backrest cover => 722619 Removing and installing cover for backrest - section on "Installing".