12 31 020 Removing and installing/replacing alternator (M57TU, M57T2)

Necessary preliminary tasks: 

• Disconnect BATTERY NEGATIVE LEAD .
• Remove fan cowl  . See 17 11 035 REMOVING AND INSTALLING/REPLACING FAN COWL WITH ELECTRIC FAN (M57T2) .
• Remove DRIVE BELT from alternator.
• Remove pressure pipe  . See 11 61 350 REMOVING AND INSTALLING/REPLACING LEFT PRESSURE PIPE (CHARGE AIR HOSE) (M57TU) or 11 61 350 REMOVING AND INSTALLING/REPLACING LEFT PRESSURE PIPE (CHARGE AIR HOSE (M57T2-SCR) .
• Remove front UNDERBODY PROTECTION .

Slacken nut (1).

Disconnect plug connection (2).

Installation note: 

The positive power supply of the preheating control unit is also connected to terminal 30 of the alternator. This lines must be connected without fail, otherwise the preheating system will fail.

Fig 1: Identifying Alternator Plug Connection And Nut

Courtesy of BMW OF NORTH AMERICA, INC.

E70, E71 only: 

Remove cover (1).

Release screw underneath.

Tightening torque: 12 31 2AZ .

Remove deflecting element (2).

Fig 2: Identifying Deflecting Element And Cover

Courtesy of BMW OF NORTH AMERICA, INC.

E70, E71 only: 

Release screw (1).

Tightening torque: 12 31 1AZ .

Release screw (2). Replace screw with inner thread. Observe tightening specification! 

Tightening torque: 12 31 3AZ .

Remove alternator (3).

Fig 3: Identifying Alternator & Screws

Courtesy of BMW OF NORTH AMERICA, INC.

All other vehicles: 

Release screw (1).

Tightening torque: 12 31 2AZ .

Remove deflecting element (2).

Release screws (3).

Tightening torque: 12 31 1AZ .

Remove alternator (4).

Installation note: 

If the Dynamic Drive optional extra is fitted, the alternator must be removed towards the bottom.

Fig 4: Identifying Alternator, Deflecting Element With Screws

Courtesy of BMW OF NORTH AMERICA, INC.

Installation note: 

Check function of DDE.