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Alternator brushes: replacement and selection

When and why it is necessary to replace alternator brushes

The alternator brushes have no lifetime limit specified and are to be replaced in case of significant abrasion of old ones. Specialists recommend to perform inspection of brushes condition every 4 years or 50 000 kilometers of mileage.

The cause of brushes premature breakdown is failures in alternator operation. In particular, inter-turn short circuit of a stator or rotor can cause negative impact on parts condition.

The signs of brushes wear-out are insufficient battery charge or its absence, voltage fluctuations in the car mains. Sudden turning off of electric equipment or dimming of light in the cabin or headlights can be noticeable during this.

Works on components installation are performed at a car servicing station. This is determined by necessity of alternator demounting and inaccessibility of the components, fastened in the brush holder. In the process of new elements installation it is recommended to assess condition of the diode bridge. By necessity, this component should be replaced too. Pay attention: if the brushes are combined with the regulator relay – this unit is replaced as an assembly.

How to select alternator brushes

The parts differ by production material. The most common are copper-graphite and carbon alternator brushes, however there are other types as well. The copper-graphite items serve longer, but at the same time cost significantly more than the carbon ones.

High-quality alternator brushes, able to provide high efficiency of the unit are produced by well-known spare parts manufacturers, who gained good reputation on the market. Bosch, Valeo, Era, DT, Magneti Marelli are among such firms.

The components differ by amount of working voltage, linear speed, current intensity, cable length and dimensions. During selection you need to consider the information, provided in the car operation manual.