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Home >> BMW >> 2009 >> 650i 2D Convertible, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 1652 (Engine Electrical System - Repair) >> Alternator With Drive And Mounting >> 12 31 020 Removing and installing or replacing alternator (N52, N52K, N51, N53)

12 31 020 Removing and installing or replacing alternator (N52, N52K, N51, N53)

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IMPORTANT: Aluminium-magnesium materials. 
No steel screws/bolts may be used due to the threat of electrochemical corrosion.
A magnesium crankcase requires aluminum screws/bolts exclusively.
Aluminum screws/bolts must be replaced each time they are released.<B> 
The end faces of aluminum screws/bolts are painted blue for the purposes of reliable identification.
Jointing torque and angle of rotation must be observed without fail (risk of damage). 

Necessary preliminary tasks: 

Unlock plug (1) and remove.

Slacken nut (2).

Installation: 

Tightening torque 12 31 1AZ .

Release screws and remove alternator (3).

Installation: 

Replace aluminum screws. 

Tightening torque 12 31 2AZ .

Fig 1: Identifying Alternator, Plug And Nut
G04751326Courtesy of BMW OF NORTH AMERICA, INC.