If the brushes are worn out and protrude from the brush holder by less than 5 mm, then replace the brush holder with brushes.
For a generator manufactured before 1996, to replace, slide the brush holder out of the voltage regulator housing by pressing on the output «IN». In order not to damage the brushes, it is necessary to remove and install the voltage regulator with a brush holder, as described above in the chapters «Generator disassembly» and «Generator Assembly».
For generators manufactured since 1996 with a non-separable regulator-brush holder assembly, the brush holder assembly with the voltage regulator is replaced.
Before installing the voltage regulator with a new brush holder in place, blow out the socket in the generator from coal dust and wipe it from oil mixed with coal dust.