Self-diagnosis method for common faults of brakes
The word "brake" is often seen in the vehicle instruction manual, which generally refers to "brake system", such as brake pad, brake pedal, and brake fluid.
For models with automatic transmission, when you step on the brake pedal, you can hear a slight "da da" sound from the gear lever. At this time, if you put your hand on the gear lever, you can also feel a slight vibration. This phenomenon is normal, and it is the sound of the gear lock solenoid valve operating.
When you lightly step on the brake pedal while driving, you can hear a sharp sizzle sound. Generally, the material of the brake pad itself is too hard or there are hard spots on the friction contact surface of the car pad. General treatment method: remove the brake pads, polish the brake pads with 60# sandpaper, or replace the brake pads.
Brake pads are vulnerable parts. If they are not replaced in time after wear, it will directly affect driving safety. If you don’t know how to check the brake pads, and you don’t want to drive a long distance to go to the 4S shop, you can ask the master to check the brake pads for you when you go to the car wash or fill up the gas.
There is no fixed replacement mileage and time for brake pads, and the replacement cycle varies according to models or personal driving habits.
The replacement cycle of drum brake pads is generally longer than that of disc brake pads. For cars with front disc and rear drum, the front brake pads are usually changed twice, and the rear brake pads are checked only once.
The brake disc (also called the brake disc) is rubbed with a bright mark by the hard spot on the brake pad. If the mark is not deep, it will not affect the braking performance, so you can ignore it. If the marks are wide and deep, affecting the aesthetics, the brake disc needs to be replaced.
If you want to replace the brake pads or brake discs, you must not only replace one side but both the left and right sides on the same shaft need to be replaced.
Touch the rim with your hands after parking. If a certain rim is particularly hot, it means that the brake cylinder of the wheel is stuck, which is what we call a "drag brake". Drag brakes may appear in vehicle deviation, shortened gliding distance, higher fuel consumption, early wear of brake pads, etc. The solution is: to clean the brake cylinder and lubricate the cylinder guide pin.
Every time you start the vehicle, after driving a short distance, you can hear a low-pitched "hum" that lasts less than a second from the engine compartment, and this sound will not repeat until the next section of the journey If it appears, it may be considered to be the normal sound of the ABS pump self-test, not a malfunction.
When the vehicle is running, if you step on the brake pedal suddenly or step on the brake on a gravel road, it is easy to trigger the ABS (anti-lock braking system) to work.
When the ABS is working, the driver will hear a "humming" sound in the cockpit, and at the same time feel that the brake pedal has a "bounce and push the foot". This phenomenon is normal and there is no need to worry.
If you brake non-emergency or step on the brake on a non-sandy road, this kind of "top foot" will occasionally occur, mostly because iron filings or other substances are absorbed on the ABS sensor (mostly installed on the steering knuckle inside the tire) Dirty things, cleaning up these dirty things can solve the problem.
The vehicle appears:
- Step on the brake at idling speed, and the speed fluctuates;
- Step on the brake at idling speed, and there is a slight air leakage sound near the brake pedal;
- After the engine is turned off, step on the brake for the first time, and the pedal will start to harden; (normally, it will gradually harden after the second foot.)
- If you step on the brakes while driving, the stroke of the brake pedal becomes shorter (the foot feels harder), and the braking effect becomes worse;
One or more of the above abnormal phenomena may be considered to be: the sealing ring of the vacuum assistant is damaged or the vacuum check valve is faulty.
Brake fluid, also known as "brake fluid", is hygroscopic and is recommended to be replaced every two years. Brake fluid is highly corrosive to leather and paint, and will feel hot if it touches the skin.
The effective stroke of the brake pedal becomes longer, and the braking effect can only be achieved by stepping on a lower position, which is commonly known as soft brakes. There are many reasons why the brakes are soft. After excluding the possibility of oil leakage, the more common reasons are:
- There is air in the brake pipeline, which can be solved by exhausting the air. (more common after repairing the brake system)
- The brake master cylinder is depressurized, and the master cylinder needs to be replaced.
- Improper adjustment of drum brake pad clearance.
If the above reasons are ruled out, the brakes are still soft, and when the brakes are stepped on, the sub-cylinder of a certain wheel has less oil output, then consider the internal pressure relief of the ABS master cylinder. (Verification method: when you press the brake pedal hard and continuously after turning off the engine, you can hear a slight sound at the ABS master cylinder, then consider replacing the ABS pump.)
During driving, the handbrake warning light on the instrument will be on or flashing (some cars will also on the ABS light). In most cases, the brake fluid is not enough. At this time, you need to go to the repair shop to check whether the brake pads need to be replaced. And whether there is any oil leakage from the brake master cylinder, subcylinder, and brake oil pipe. If there is no abnormality, add the same type of brake oil to the appropriate level.
Step on the brake pedal lightly when the speed is fast, and you can feel the steering wheel vibrating (or vibrating) from side to side. Release the brake pedal, and the vibration will disappear immediately. This is caused by the unevenness of the front brake disc, which needs to be ground or replaced. Front brake disc.
