12 31... Replacing alternator belt pulley

WARNING: This page is about a different car, the 2010 BMW 135i, 2009 BMW 135i, and 2008 BMW 135i. However, it is still accessible from the selected car via links, so may be relevant.

Special tools required:

12 7 121
12 7 122

See ENGINE ELECTRICAL SYSTEM - SPECIAL TOOLS .

Illustrations show N42:

If fitted, remove cover cap from belt pulley.

Depending on alternator type, hold down alternator axis with:

Torx socket wrench
Hold inner multi-wrench tool (special tool 12 7 122).

Release freewheel with special tool 12 7 121 and remove.

Fig 1: Griping Freewheel Using Special Tool 12 7 121

Courtesy of BMW OF NORTH AMERICA, INC.

Installation:

Tightening torque 12 31 8AZ, see 12 31 ALTERNATOR WITH DRIVE AND MOUNTING PARTS .

Procedure with special tool 12 7 123.

Depending on alternator type, hold down alternator axis with:

Torx socket wrench
Hold inner multi-wrench tool (special tool 12 7 122).

Fig 2: Griping Freewheel Using Special Tool 12 7 123

Courtesy of BMW OF NORTH AMERICA, INC.

Release freewheel with special tool 12 7 123 and a ring spanner and remove.

Installation:

Tightening torque 12 31 8AZ, see 12 31 ALTERNATOR WITH DRIVE AND MOUNTING PARTS .