What are the causes of a generator carbon brush failure?
3 Answers
Generator carbon brush failure is caused by: 1. Contamination on the surfaces of the slip ring, carbon brush, brush holder, and brush frame; 2. Sticking of the brush holder edges or uneven spring pressure; 3. Excessive vibration in the unit's shaft system, causing the slip ring to vibrate as well. The solutions for generator carbon brush failure are: 1. Completely remove the burnt mica, eliminate grounding faults, fill the groove with asbestos thread, compact and smooth it, then continue using; 2. If the diode is damaged, cut its lead wire or replace the diode; 3. If the carbon brush is broken, remove it, shape the carbon rod from a dry battery into a carbon brush shape, cut a small groove at the top of the carbon brush, wind a wire around it, and use it as an emergency measure; 4. If the pulley is loose, insert hard objects such as iron wire into the half-round key to tighten the pulley and shaft, securing the pulley.
The generator carbon brushes were damaged, and I've encountered this issue with my own car before. That time, after a long trip, I suddenly noticed the car lights flickering, and upon inspection, found the generator carbon brushes were worn out. The main reasons: first, normal wear and tear—carbon brushes constantly rub against the brush holder, thinning over time until they're as thin as paper; second, high heat and dust inside the engine compartment—the engine heat makes the carbon brushes brittle, speeding up the damage; third, my usual neglect of maintenance—not regularly cleaning dust and oil buildup, which accelerates wear when dirt accumulates. I’ve learned to take a quick look under the hood while refueling and clean out any dust, which helps prevent bigger issues. If the carbon brushes do fail, the car will show a battery warning light, and charging will malfunction—replace them immediately, or the entire generator could be ruined. I recommend using OEM parts; cheap alternatives won’t last long, and saving a little now could cost a lot more in full repairs later.
The generator carbon brushes are problematic, and my old car often has this issue. I reckon the main reason is prolonged wear and tear—that little thing is constantly rubbing, and after a few years, it naturally falls apart. Also, if the car is always driven on rough, bumpy roads, like gravel paths, the vibrations can loosen or break the carbon brushes. On top of that, low-quality replacement parts don’t help—I once bought cheap carbon brushes that lasted only three months. I try to stay vigilant by regularly checking the car’s charging system; if I notice slower charging, I take it to the shop. Don’t underestimate this issue—it can prevent the battery from fully charging, dim the lights, and make nighttime driving especially dangerous. A cost-saving tip is to replace small parts regularly before they damage the generator, as that repair bill can get steep.
