Different types of faults and diagnostic techniques in automotive braking system

1、 Sudden brake failure in the car braking system and corresponding diagnosis provided

There are four main reasons for sudden brake failure during the braking process of a car's braking system. Firstly, it may be due to a brake failure caused by a lack of brake fluid in the master cylinder of the braking system; Secondly, it may be due to the leather bowl in the brake master cylinder of the braking system being stepped over or damaged, resulting in brake failure; Once again, it is possible that the brake failure was caused by the rubber bowl in the brake cylinder of the braking system being stepped over or damaged; Possible brake failure caused by severe damage to the brake pipeline in the braking system.

When the braking system of a car malfunctions, stop immediately and conduct a check for the brake failure issue. We need to first observe whether there is a leakage problem in the braking system, which often occurs in the push rod braking position of the brake master cylinder. If it is determined through observation that there is a leakage problem in the master cylinder of the brake system, we should consider the damage or overturning of the brake master cylinder's cup; If there is a problem of brake fluid leakage at the position of the brake wheel, we need to consider the damage or overturning of the brake cylinder cup. During the process of brake fluid leakage, the problem of brake pipeline leakage is checked and generally diagnosed through observation.

2、 Fault of brake biting in car braking system and corresponding diagnosis provided

The problem of brake biting occurred during the braking process of the car, mainly due to the lack or detachment of the brake pedal return spring, resulting in the brake system not having free travel; Car pedal bracket; The problem of corroded pedal shafts can also lead to brake biting in the braking system; There is a small gap between the friction pads of the brake shoes and the brake drum, which can also cause brake biting problems in the braking system; Damaged or swollen brake master cylinder cups in the braking system can also lead to brake biting issues; Failure to replace and clean the brake fluid in the braking system in a timely manner can result in dirty brake fluid and cause brake biting problems in the braking system.

In the process of fault diagnosis, we need to release the brake pedal of the braking system. If the brake wheel still has braking function in the relaxed state, it indicates that there is a problem of brake biting in the braking system; If the brake wheel hub overheats during the driving process of the car, it indicates that the brake master cylinder in the braking system has malfunctioned and further troubleshooting is needed. This troubleshooting process is mainly aimed at the brake master cylinder in the braking system. If some of the brake wheels have brake biting problems, it is possible that some of the brake wheels have blocked brake pipelines, causing the cylinder in the brake system to be unable to return oil. If there are still some brake wheel biting problems after corresponding actions, we need to consider the appropriate issue of brake clearance. If the brake clearance is too small, it can also cause brake wheel biting problems. If the above inspection steps are normal, we need to check the brake cylinder return spring in the brake system.

3、 Fault of unilateral brake deviation in car braking system and corresponding diagnosis provided

If the braking action deviates to one side during the braking process of a car, it is a unilateral braking deviation problem in the braking system malfunction. The main cause of this problem is the difference in clearance between the brake wheel hub and the friction plate. If there is a significant gap between the two sets of brake wheels and friction plates in a day, it will cause differences in the quality of the friction plates, which in turn will lead to differences in the inner diameter of the brake drum, resulting in the above-mentioned phenomenon. The piston of one side of the front wheel cylinder has excessive friction with the cylinder, there is air in one side of the front wheel cylinder, the hose is aging or the cylinder cup is poor, or the brake drum on one side of the front wheel is out of circle, the air pressure of the two front tires is inconsistent, and the friction plate of one side of the front wheel is oily, wet, hardened, and the rivet is exposed.

During the inspection, first conduct a road test to brake and identify the wheels with poor braking efficiency based on tire drag marks for repair. Wheels with short or no trailing marks are considered to have poor braking efficiency. You can first check whether the brake pipeline of the wheel leaks oil and whether the tire pressure is sufficient. If normal, the clearance between the high-speed friction plate and the brake drum can be maintained. If it still doesn't work, check if the air has seeped into the pump. If there is no air infiltration, remove the brake drum and inspect each component of the brake one by one according to the cause. If it is also normal, it indicates that the fault is not in the braking system. The technical condition of the frame or front axle and the condition of the steering mechanism should be checked. If there is a brake test bench for convenience, check which wheel has lower braking force, which is the defective wheel.