What is the cause of the failure of automobile starter?

I asked Master Chebang for leave at Chebang Q&A before. It feels quite reasonable. I hope I can help you. Ha ha. Causes of starter failure: 1, too long starting time, failure to use the starter according to the specified time (about 5s ~ 10s), and long-term use of the starter without finding out the reasons. 2, when the brush wear to the original length 1/2, should replace the brush. When repairing the starter, check the height and contact of the brush regularly, and eliminate the problems in time if found, otherwise the starter will be scrapped. 3. The electromagnetic switch has poor contact, and the unidirectional teeth and flywheel teeth are damaged. Poor iron strike of the iron strike line and so on will cause the failure of the starter. You should go into the factory for maintenance as soon as you find that the startup is faulty.