Note: Additional instructions for 520i/525i models from May 1990 are at the end of this section.
Withdrawal
On models 518i, 520i, 525i: Disconnect the ground wire from the battery.
On models 530i, 535i, 524td, 525tds. Disconnect the battery terminal at the bulkhead connector.
Attention: When the battery is disconnected, the information in the electronic memory devices, such as the engine trouble memory or the radio security code memory, is erased. When disconnecting the battery, follow the instructions in section "Removing and installing the battery".
Release tension and remove V-belt.
Release hose clamp 2 and detach air hose from alternator. The hose is routed from the alternator to the left headlight housing.
On models 520i, 525i: Remove filter housing and air mass meter.
Remove the protective cover from the terminal block on the generator.
Bosch alternator: Remove wires from terminal B+ (terminal 30) and D+ (terminal 61) Unscrew ground wire (terminal 31).
Loosen the alternator mounting bolt, remove the alternator.
Installation
Check the alternator suspension bushings and, if necessary, replace them.
Insert alternator and secure with screws.
Insert the tension roller and fasten it with a bolt.
Connect electrical wires to the generator: B+ (terminal 30), D+ (terminal 61) and mass jumper (terminal 31).
Fit and tighten the V-belt.
Connect ground wire to battery or connector.
M50 engine. 520i/525i models since May 1990 (Four-valve engine with ribbed V-belt)
Withdrawal
Loosen the bolts and pull out the alternator with the bypass roller.
Installation
When installing the idler roller, ensure that the retaining lug is inserted into the groove on the bearing.
Tighten bolts and fit ribbed V-belt.