Generator repair

Golf, Jetta, and Scirocco models can be fitted with one of two types of alternators: Bosch or Motorola (pic. D:7, D:8, D:9). The following procedure for replacing the brushes and voltage regulator applies to both types of generators, as their design is basically the same.

Replacement of brushes and voltage regulator

The brushes are installed in a brush holder attached to the voltage regulator. Remove the alternator from the vehicle as described previously. Loosen the screws securing the regulator (shown by arrows in fig. D:4, D:5) and remove the regulator and brush assembly. Measure the free length of the brushes as follows:


1. Inspect the brushes for wear. In a free position, measure the length of the part of the brushes protruding from the brush holder (Ah, fig. D:10 and D:11). If the free length of the brushes approaches the specified in the section "Technical data" or less, replace the brushes.

2. Unsolder the brush guides from the holder and remove the old brushes from their sockets. Carefully solder the conductors of the new brushes (pic. D:11, D:12).

3. Install the new brushes in the slots and make sure the brushes move freely.

When installing a new voltage regulator, the brushes should also be replaced. The regulator comes with a brush holder to which new brushes must be soldered as described earlier. The connections on the Motorola alternator are slightly different from those described (pic. D:13, D:14).

Install the voltage regulator assembly with brush holder to the back of the generator and secure with bolts. Mount the alternator to the vehicle and test the output current under load as previously described.