Replacing the radial shaft seal for the drive flange of the front axle differential

Preliminary work 

• Refer to DEACTIVATING THE 48 V ELECTRICAL SYSTEM .
• Refer to DISCONNECTING ALL BATTERY GROUND LEADS .
• Refer to REMOVING REAR UNDERBODY PROTECTION .
• Refer to REMOVING THE UNDERBODY PLANKING OF THE TRANSMISSION ON THE SIDE .
• Refer to REMOVING THE STIFFENING PLATE .
• Refer to REMOVING TRANSMISSION CROSS-MEMBER .
• Refer to REMOVING THE CONNECTING SUPPORT FROM THE TUNNEL .
• Refer to IF INSTALLED: REMOVING THE TORSION STRUT ON THE RIGHT AND LEFT WHERE REQUIRED .
• Refer to REMOVING COMPLETE EXHAUST SYSTEM .
• Refer to REMOVING THE HEAT SHIELDS .
• Refer to REMOVING THE RETAINING PLATES .
• Refer to PARTIALLY LOOSENING THE PROP SHAFT .
• Refer to REMOVING THE TRANSFER BOX (ATC 13-1) .
• Refer to REMOVING THE PROP SHAFT FRONT AT THE FRONT AXLE TRANSMISSION .

Remove the input flange of the front axle differential 

• Mark position of nut with respect to shaft with punch marks (arrow).
• Lever out and remove lock plate (1) with a suitable tool.

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• Position special tool 0 492 185 (33 2 140)  with one screw (M8x30) (1) on the drive flange.
• Hand-tighten the screw (M8x30) (2) through the bore on the drive flange with a nut (M8) (3).
• Tighten screw (M8x30) (1) hand-tight.
• Release nut (4). Counter support on the special tool 0 492 185 (33 2 140)  while doing so.

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• Loosen screws (1). Remove the (M8) nut while doing so.
• Remove special tool 0 492 185 (33 2 140). 

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• Position the special tool 2 466 854  on the drive flange (1).
• Hand-tighten the bolts (2).
• Pull down the drive flange (1) by turning the spindle on the special tool 2 466 854  from the bevel drive pinion and remove it. Counter support with a suitable tool (3) on the special tool 2 466 854. 

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• Cut a small hole in a cloth (1).
• Slide cloth (1) over bevel drive pinion (2).

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• Use thread file (1) to remove the adhesive residue.

  Pay attention to the correct thread length without fail! 

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  NOTE: TECHNICAL INFORMATION 
  Keep the connection on the bevel drive pinion of the front axle transmission clean and free of oil and grease.
• Thoroughly clean the thread all around on the bevel drive pinion (1) with the thread files (2) from the adhesive residues.
• Clean the thread and the gearing on the bevel drive pinion (1).

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• Remove the cloth from the bevel drive pinion (1).

  Removing the radial shaft seal of the drive flange 

• Lift out and remove the radial shaft seal (1) from the front axle transmission using a suitable tool (2).

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• Replace the radial shaft seal for the drive flange of the front axle differential.

  Parts:  Radial shaft seal

  Installing the radial shaft seal of the drive flange 

• Coat the sealing lips of radial shaft seal with front axle differential oil.
• Use special tool 0 493 539 (31 5 130)  to strike the radial shaft seal up to the stop of the front axle transmission.

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  Install the input flange of the front axle differential 

  NOTE: TECHNICAL INFORMATION 
  Keep the connection on the bevel drive pinion of the front axle transmission clean and free of oil and grease.
• Clean the gearing on the drive flange (1).
• Unscrew the spindle from the special tool 2 466 854. 
• Position the drive flange (1) with the special tool 2 466 854  on the front axle transmission and tap it with a rubber mallet (2) up to the stop on the drive shaft.

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• Loosen screws (3).
• Remove the special tool 2 466 854. 
• Position special tool 0 492 185 (33 2 140)  with one screw (M8x30) (1) on the drive flange.
• Hand-tighten the screw (M8x30) (2) through the bore on the drive flange with a nut (M8) (3).
• Tighten screw (M8x30) (1) hand-tight.
• Unscrew the nut (4) manually on the drive shaft.

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  NOTE: RISK OF DAMAGE 
  Damage to the front axle differential. If the nut is tightened beyond the punch mark, the clamping sleeve and therefore the front axle differential is damaged. 

  • Only tighten the nut up to the punch mark.

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• Tighten the nuts (1) until the punch marks (arrow) on the nut and the drive shaft match. Counter support by using the special tool 0 492 185 (33 2 140). 
• Loosen screws (2). Remove the nut (M8) while doing so.
• Remove special tool 0 492 185 (33 2 140). 
• Replace the lock plate (1).

  Parts:  Lock plate

• Position and insert lock plate (1).

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Follow-up work 

• Refer to INSTALLING THE FRONT PROP SHAFT .
• Refer to INSTALLING THE TRANSFER BOX (ATC 13-1) .
• Refer to DISCONNECTING ALL BATTERY GROUND LEADS .
• Refer to ACTIVATING THE 48 V ELECTRICAL SYSTEM .
• Refer to CHECKING/TOPPING UP THE TRANSFER BOX OIL (ACTIVE TORQUE CONTROL 13-1) .
• Refer to CHECKING/ADDING FRONT AXLE TRANSMISSION OIL .
• Refer to FASTENING THE PROP SHAFT (PARTIALLY REMOVED) .
• Refer to INSTALLING THE RETAINING PLATES .
• Refer to INSTALLING THE HEAT SHIELDS .
• Refer to INSTALLING THE COMPLETE EXHAUST SYSTEM .
• Refer to IF INSTALLED: INSTALLING THE TORSION STRUT ON THE RIGHT, AND ON THE LEFT WHERE REQUIRED .
• Refer to INSTALLING THE CONNECTING SUPPORTS ON THE TUNNEL .
• Refer to INSTALLING TRANSMISSION CROSS MEMBER .
• Refer to INSTALLING THE THRUST FIELD .
• Refer to INSTALLING THE UNDERBODY PLANKING OF THE TRANSMISSION ON THE SIDE .
• Refer to INSTALLING REAR UNDERBODY PROTECTION .