Removing and installing backrest adjustment motor: Audi A4 B8

🧭 Before you start

Remove the seat and fit it to a repair stand, then remove the trims and backrest cover panel. Mark the backrest fitting positions, undo the shaft nut, detach the padding and pull the shaft. Unplug and unbolt the motor. Check both fittings against the marks, align the shaft and motor mounting using a 12 V supply, fit new bolt and nut with locking fluid and reconnect.

Fits: Audi A4 B8 (8K, 2007–2015)

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• Mark the backrest fitting angle on both sides before removing the shaft, without scratching the fittings.
• Renew the motor bolt and shaft nut and use locking fluid on both.
• Align the shaft profile with the motor mounting, rotating it with a 12 V supply if needed.
• Discharge static before touching side airbag connectors.
• Reconnect the battery with the ignition on and nobody in the car.

Written for this job from the workshop steps below · TorqFix editorial.

📋 Procedure

1. ⚠ Observe safety regulations for pyrotechnic components .Before handling airbag units (e.g. unplugging the electrical connector) the mechanic must discharge any static electricity. This can be done by briefly touching the door striker plate, or similar. — Remove front seat:
2. Attach front seat to seat repair standVAS 6136.
3. Remove trim (tunnel side and sill side ).
4. Remove backrest cover panel:
5. Mark angularity of backrest fittings (left and right) on seat as follows:

6. Use an indelible pen to make mark (line) (arrow B) on backrest (2) directly at front edge (arrow A) of fitting (1).
7. ⚠ When making mark, take care not to damage surface of fitting (scratching or scoring). — Remove nut (4) from shaft (3).
8. Detach padding from backrest .
9. Pull shaft (3) out of outer backrest frame (1) in direction of (arrow).
10. Unplug electrical connector (6) at backrest adjustment motor (7).
11. Remove bolt (2).
12. Detach backrest adjustment motor from retainer (5).
13. ⚠ Observe safety regulations for pyrotechnic components .Before handling the airbag units (e.g. plugging in the electrical connector) the mechanic must discharge static electricity by briefly touching the door striker plate, or similar. — Clean shaft thread (3) before installing, e.g. using a thread tap.
14. Check position of outer backrest frame (2) and fitting (1) on left and right side of backrest.
15. If the outer backrest frame is not in the position marked before removal (on left and right side), make adjustments as required.
16. Position backrest adjustment motor (1) on retainer (3).
17. Renew bolt (4), coat with locking fluid (Electronic parts catalogue) and hand-tighten only.
18. First slide shaft through fitting (tunnel side) as far as mounting (2) in backrest adjustment motor.
19. Check that profiles of inserted shaft and mounting (2) in backrest adjustment motor are in line.
20. Push shaft through mounting in backrest adjustment motor as far as stop (sill side).
21. Apply an external power source (12 V) to backrest adjustment motor (1).
22. Rotate mounting (2) until profiles of shaft and mounting are in line.
23. Push shaft through mounting in backrest adjustment motor as far as stop (sill side).
24. Apply locking fluid (Electronic parts catalogue) to threaded section of shaft.
25. Fit new nut (4) on shaft (3) and tighten.
26. Secure backrest adjustment motor to retainer (3) (with specified torque). [Note: Make sure electrical connectors are fitted correctly (as far as stop) and engage audibly.]
27. ⚠ The battery must be connected with the ignition switched on. If pyrotechnic components (e.g. airbag or belt tensioner) are inexpertly repaired, this may result in unwanted triggering after connecting the battery. There must not be anyone in the vehicle while you are connecting the battery. — With ignition switched on, connect battery earth wire Electrical system27Battery; Disconnecting and connecting battery. [Note: If the airbag warning lamp K75 indicates a fault following installation, you must interrogate, erase and then re-interrogate the event memory .]

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