12 31 020 Removing and installing or replacing alternator (M52, M52TU, S50US, S52, M54, M56)

Necessary preliminary tasks:

If necessary, drain supply tank for power steering pump, remove with holder and place to one side.

NOTE: Lines on supply tank for power steering pump remain connected.

If fitted:

Remove air hose.

Fig 1: Removing Air Hose

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Version 1

Take off cap on connections.

Disconnect plug connection (1).

Release nut (2) and disconnect battery positive lead.

Fig 2: Disconnecting Plug Connection

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Version 2

Unlock and detach plug connection (1).

Release nut (2) and disconnect battery positive lead.

Fig 3: Unlocking & Detaching Plug Connection

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Version without idler pulley:

Release alternator screws in succession while simultaneously gripping alternator firmly.

Remove alternator.

Fig 4: Identifying Alternator

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Version with idler pulley:

Remove cover from idler pulley (1).

Release screw and remove idler pulley (1).

Release screw and remove alternator (2).

Fig 5: Removing Cover From Idler Pulley

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Version with idler pulley:

Installation:

Turning lock of tensioning roller must engage in alternator groove.

Fig 6: Turning Lock Of Tensioning Roller

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Interrogate fault memory of DME control unit.

Now clear the fault memory.