Removing and installing gear for backrest adjustment - RA91001290125X(91-125)

Front seat removed (91-100) 

Side covering on backrest frame removed (91-60)

Covering on rear of front seat backrest removed (91-065) 

Operation no. of operation texts and work units standard texts and flat rates

Flexible drive shaft (1)	remove.
Motor (2)	unscrew (4 screws).
Toothed belt (3)	remove.
Motor (2) on driver's backrest	screw on hand-tight.
Clamping pin (4) on backrest lock	knock out, 3 mm diameter, while holding with setting iron or hammer. Observe installation note.
Screws (5)	2 each (12 mm Allen screws) unscrew. Observe installation note
Gear spindle (6) on backrest lock	unscrew.
Gear (7)	remove.
Gear spindle (6)	screw into backrest lock until clamping pin (4) can still just be knocked in.
Screws (5)	2 each (12 mm Allen screws), screw in.
Clamping pin (4)	install. Total length 30 mm.
Adjust backrest lock	see gear, outside of seat.
Continue to reinstall	in opposite order.

Gear on outside of seat 

Flexible drive shaft (1)	remove.
Clamping pin (8) on backrest lock	knock out, 3 mm diameter, while holding with setting iron or hammer.
Screws (9)	2 each, 12 mm Allen screws, unscrew. Observe installation note.
Stop cable	fold away downward.
Gear spindle (10) on backrest lock	unscrew.
Gear (11)	remove.
Gear spindle (10)	screw into backrest lock until clamping pin (8) can just be knocked in.
Screws (9)	2 each (12 mm Allen screws), screw in while simultaneously inserting the stop cable eye.
Stop cable eye	do not pinch when tightening screws (9).
Clamping pin (8)	install, total length 37 mm.
Both gear spindles (6 and 10)	screw all the way up against the stop.
Backrest lock	check, both locks must catch simultaneously and completely.
Adjust backrest lock	by turning gear drive shaft slightly to correct.
The control cables on the backrest lock	must be adjusted to play of 0 - 1 mm.
Flexible drive shaft (1)	install and fasten with mount on backrest frame.
Check backrest lock	with both microswitches (Diagnosis Manual).
Continue to reinstall	in opposite order.

Installation note 

The clamping pins in the backrest locks have different lengths and are therefore not interchangeable.

Backrest lock - inside of seat 

Clamping pin length 30 mm

Dia. 3 mm

Backrest lock - outside of seat 

Clamping pin length 37 mm

Dia. 3 mm

The gear screws (5 and 9) on the left and right gears have different screw head lengths and are therefore not interchangeable.

The screw with the screw head length of 12 mm is for the gear on the inside of the seat.

The screw with the screw head length of 18 mm is for the gear on the outside of the seat.

The threads on the gear screws (5 and 9) are micro-encapsulated and must be replaced after disassembly or coated with screw securing agent. Tightening torque: 35 Nm.

Removal, installation 

Gear on inside of seat 

1. Unscrew mount on backrest frame and pull flexible drive shafts on left and right out of gear drive shafts.
   Fig 3: Locating Backrest Frame

   
2. Unscrew screws and remove toothed belt from motor.
3. Screw motor back onto driver's backrest and tighten hand-tight.
4. Unlock backrest and tilt forward.
   Fig 4: Identifying Backrest Screws

   
5. Knock out clamping pin, diameter 3 mm, while holding with setting iron or hammer (arrow).
   Fig 5: Locating Clamping Pin

   
6. Unscrew screw on outside (arrow).
   Fig 6: Unscrewing Screw On Outside

   
7. Unscrew screw on inside (arrow).
   Fig 7: Unscrewing Screw On Inside

   
8. Screw gear spindle out of backrest lock manually.
9. Remove gear.
   Fig 8: Screwing Gear Spindle Out Of Backrest Lock

   
10. Check plastic bushings, replace if damaged (arrows).
    Fig 9: Locating Plastic Bushings

    
11. Screw gear spindle into backrest lock so that the clamping pin can still just be knocked in.
    Fig 10: Screwing Gear Spindle Into Backrest Lock

    
12. Screw in inner and outer screws. Observe installation note.

    Tightening torque: 35 Nm.

    Fig 11: Locating Inner And Outer Screws

    
13. Install clamping pin.

    Length of clamping pin: 30 mm.

    Fig 12: Locating Clamping Pin

    
14. Turn left and right gear spindle all the way up against the stop. To do this stick flexible drive shaft onto gear drive shaft and turn manually.
    Fig 13: Locating Left And Right Gear Spindle

    
15. Check backrest lock; both locks should catch simultaneously and completely.
    Fig 14: Locating Backrest Lock

    
16. The backrest lock adjustment can be corrected by turning the gear drive shaft slightly.
    Fig 15: Locating Backrest Lock

    
17. In the locked state the control cables for the backrest lock should have play of 0 - 1 mm.
    Fig 16: Locating Control Cables

    
18. Install toothed belt and tension. Adjust toothed belt tension to play of 3 - 7 mm at a manual force of approx. 30 N.
    Fig 17: Adjusting Toothed Belt Tension

    
19. Install flexible drive shaft without changing adjustment made previously on gear drive shafts.
    Fig 18: Locating Flexible Drive Shaft

    
20. Lock backrest locks and ensure that they are completely locked by electrically checking the microswitches on the left and right (see Diagnosis Manual, Body, Volume 1, Section 4.1, Model R 129).
21. Continue to reinstall in opposite order.
    Fig 19: Locating Backrest Locks

    

    Gear on outside of seat 

22. Remove flexible drive shaft (arrow).
23. Knock out clamping pin, 3 mm diameter, on backrest lock while holding with setting iron or hammer (arrows).
    Fig 20: Locating Clamping Pin

    
24. Unscrew screw on outside (arrow).
    Fig 21: Unscrewing Screw On Outside

    
25. Unscrew screw on inside (arrow).
    Fig 22: Unscrewing Screw On Inside

    
26. Pull stop cable down and out (arrow)
27. To improve access to the gear spindle disconnect pull cable for backrest release on backrest lock.
    Fig 23: Locating Cable

    
28. Unscrew gear spindle manually on backrest lock (arrow).
29. Remove gear.
    Fig 24: Locating Backrest Lock

    
30. Before installing gear check plastic bushings, replace if damaged. Install both bushings with the collar pointing inward.

    Plastic

    bushing on inside

    Fig 25: Locating Plastic Bushings - Bushing On Inside

    

    Plastic

    bushing on outside

    Fig 26: Locating Plastic Bushings - Bushing On Outside

    
31. Insert gear into backrest strut and turn gear spindle into backrest lock until the clamping pin can still just be knocked in (arrow).
32. Hook in and clip on control cable for backrest release.
    Fig 27: Locating Control Cable

    
33. Screw in screws on outside and inside while inserting stop cable; do not pinch cable eye.

    Observe installation note.

    Tightening torque: 35 Nm.

    Fig 28: Locating Screw

    
34. Install clamping pin.

    Length of clamping pin: 37 mm.

    Fig 29: Locating Clamping Pin

    
35. Turn left and right gear spindle all the way up against the stop. For this purpose stick flexible drive shaft onto gear drive shaft and turn manually.
    Fig 30: Identifying Gear Spindle Position

    
36. Check backrest lock; both locks should catch simultaneously and completely.
    Fig 31: Locating Backrest Lock

    
37. The backrest lock adjustment can be corrected by turning the gear drive shaft slightly.
    Fig 32: Identifying Gear Drive Shaft Position

    
38. The pull cables for releasing the backrest must be adjusted to a play of 0 - 1 mm in the locked state.
    Fig 33: Locating Cables

    
39. Install flexible drive shaft and screw onto backrest frame with mount without turning the previously adjusted gear shafts.
    Fig 34: Locating Flexible Drive Shaft

    
40. Lock backrest lock and ensure that they are completely locked by electrically checking the microswitches on the left and right (see Diagnosis Manual, Body, Volume 1, Section 4.1, Model R 129).
    NOTE: When the front seat backrest is completely locked a play of 15 - 20 mm is permissible at the top of the backrest.
41. Continue to reinstall in opposite order.
    Fig 35: Locating Front Seat Backrest