Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
12 31... Replacing alternator belt pulley
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.
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).
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 .
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.