1. Pay attention to the feel and braking distance of the brake at ordinary times. If the brake oil is not replaced in time, it will cause the brake oil to be turbid, the boiling point will drop, the effect will become worse, and the brake will fail;
2. Because the brake oil system always wears, and there are many impurities in the low-end brake oil, this will lead to accelerated wear of the brake pump and blockage of the brake system oil circuit. The braking effect of expired brake oil is not ideal, just because the owner has adapted to his vehicle for a long time, so he can't notice it. For the sake of driving safety, it is recommended to replace it immediately.