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Home >> BMW >> 2018 >> 640i >> Repair and Diagnosis >> Accessories & Equipment >> Gauges & Instrument Panels >> Engine Electrical System - Repair - F12 >> Alternator With Drive And Mounting >> 12 31 020 Removing and installing or replacing alternator (N55)

12 31 020 Removing and installing or replacing alternator (N55)

Necessary preliminary work: 

NOTE: In order to remove the alternator, it is necessary to REMOVE the air conditioning compressor. 
In so doing:
  • Do not  draw off A/C system refrigerant.
  • Do not  detach refrigerant lines from A/C compressor.
  • Do not  remove air conditioning compressor; instead, release from bracket only and place to one side.

Release screws (1).

Tightening torque 12 31 1AZ .

Fig 1: Identifying Screw And Holder
G09875408Courtesy of BMW OF NORTH AMERICA, INC.

Release screw (2).

Tightening torque 12 31 2AZ .

Release screw (3) and remove with holder (4).

Tightening torque 12 31 2AZ .

Fig 2: Identifying Protective Cap And Connector
G09875409Courtesy of BMW OF NORTH AMERICA, INC.

Unlock connector (1) and remove.

Remove protective cap (2) and release nut underneath.

Tightening torque 12 42 1AZ .

Remove positive battery cable (3).

Fig 3: Identifying Screws And Alternator
G09875410Courtesy of BMW OF NORTH AMERICA, INC.
NOTE: For purposes of improved clarity, illustrations and description show A/C compressor removed.

Release screws (1) a few turns until bracket (2) is loose. Do not remove bracket (2).

Tightening torque 12 31 3AZ .

Feed out alternator (3) and remove.

Assemble engine.