The overrunning alternator pulley, also known as the alternator freewheel clutch, must be checked regularly to ensure that the unit drive is functioning correctly and to prevent damage.
An alternator freewheel clutch can be tested as follows:
A defective freewheel can be identified by the unit drive not running truly and the ensuing noise. An alternator with an intact freewheel should slow down and come to a standstill when the engine is switched off.
If the freewheel is working correctly, the shaft will rotate freely in one direction and is locked in the other direction. Depending on the manufacturer, there may be increasing resistance in the locked direction.
The alternator freewheel clutch must be replaced if the above results are not achieved.
The overrunning alternator pulley must always be tested whenever any repair work is performed on the unit drive.
We recommend the following procedure:
Please observe the relevant vehicle manufacturer's repair and maintenance instructions in this regard.
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