Brake pedal failure
1. Braking failure
Performance: When using the brake while driving, the car cannot slow down or stop; after one or more continuous braking, the brake suddenly does not work.
Cause of failure: It may be oil or air leakage in the brake pipeline, rupture or falloff of the pipeline joint, failure of the brake sealing element, etc.
Treatment method:
(1) If there is no sense of connection between the brake pedal and the brake master cylinder, it means that the connection between the brake pedal and the brake master cylinder is loose, and it should be checked and repaired. .
(2) If you feel light and slight resistance when depressing the brake pedal, you should check whether the brake fluid in the master cylinder reservoir is sufficient. If there is no fluid in the master cylinder reservoir or there is a serious lack of fluid, brake fluid should be added to the specified level. If there is still no resistance when the brake pedal is depressed again, check whether the brake hose or metal pipe from the brake master cylinder to the brake wheel cylinder is broken and leaking oil.
(3) When you step on the brake pedal, although you feel a certain resistance, the pedal position cannot be maintained and sinks significantly, you should check whether the dust boot of the brake master cylinder has a brake. Dynamic fluid leakage. If there is brake fluid leakage, it means that the brake master cylinder cup is broken; if there is a large amount of brake fluid on the edge, you should check whether the brake wheel cylinder cup is overturned and whether it is severely worn.
2. Not returning to position
Performance: After pressing the brake pedal, the pedal neither If there is no resistance when it rises, even if you don’t step on the brake pedal, you will still obviously feel the resistance of the car. In severe cases, the wheels may even lock.
Cause of failure: The air brake master cylinder and wheel cylinder parts are damaged, or there is rust inside the brake wheel cylinder.
Processing method:
(1) Clean the rust and impurities in the piston and piston cylinder.
(2) Remove the guide pin, grind and clean the rusted part.
(3) Replace with a new brake cylinder. [Details>>]
3. The foot brake is shaking
Cause of failure: eccentric wear of the brake disc; aging of the engine foot pad; brake disc, joint Unevenness of the head plane and shaft head plane, etc.
Treatment method: Grind and smooth the rust on the brake disc, replace the brake disc with a new one, and replace the deformed parts. 【detailed>>]
4. Brake drag
Performance: After the driver completely relaxes the brake pedal, the car’s brake cannot be released immediately or This phenomenon cannot be completely eliminated but still has considerable braking force. The specific symptom is that the car is still decelerating after releasing the brakes, and the brake pads are overheated or even ablated.
Cause of failure: brake pedal has no free travel, brake pedal return spring is broken or missing, brake master cylinder failure, brake cylinder is rusted or stuck, brake shoe support pin is corroded, brake The gap between the pad and the brake basin is too small, the brake pad return spring is broken or missing, the brake oil is too dirty, the viscosity is too high and the oil return is difficult, the wheel hub bearing is loose or damaged, etc. For models with ABS systems, ABS Pump failure can also cause brake drag.
Treatment method: The vast majority of brake drag failures are caused by corrosion of brake transmission parts. We can generally eliminate brake drag by disassembling, removing rust, and lubricating these parts. failure.
5. Braking sideslip or deviation
Performance: The car veers to one side when braking, mainly on the left and right sides. Caused by inconsistent power or braking time.
Cause of the fault: It may be that the gaps between the brake elements on both sides are unequal, the brake friction pad on one side is oily, the return elastic element on one side fails and the brake shoe cannot return, the frame is deformed, and the front Axis shift etc.
Treatment method:
(1) If the sealing ring of the brake wheel cylinder is found to be damaged, or the brake air pipe or oil pipe is leaking oil or air, it should be replaced.
(2) The piston of the brake cylinder is biting. The wheel cylinder piston should be replaced.
(3) The left and right brake pads have different wear. Give replacement.
(4) The left and right brake friction plates have different materials, uneven thickness, and different friction coefficients, etc. Adjustments and replacements should be made consistent.
(5) Check the brake friction pads for oil stains, etc. should be cleared.
6. Abnormal noise
Cause of failure: It may be that the brake friction pads are severely worn or the friction pads are damaged, the drive shaft splines are loose or the connecting bolts Loose etc.
Processing methods:
(1) If the vehicle is equipped with an ABS braking system, the braking sound may be caused by the system. Because whenever the road conditions are poor, the ABS braking system will play its role, so it is normal for abnormal noise to occur in this situation.
(2) You can go to the repair shop to check whether there is any foreign matter entering the brake system. Because the entry of foreign objects will cause noise in the braking system.
(3) The “brake wheel cylinder” is to push the brake pads. Its function is to make the brake pads rub against the brake drum to achieve normal braking. This brake cylinder is very important to the braking system! When driving on a daily basis, it is very important to clean the brake pump. If it is not cleaned for a long time, various foreign matter will accumulate.Among them, various abnormal noises will also occur.
(4) Brake pads are consumables. Under normal driving conditions, the brake pads must be inspected after the car has traveled 5,000 kilometers. Whether replacement is needed depends on the specific situation. If the brake pads are excessively worn, it is reasonable to make abnormal noise.
7. Alert light warning
Cause of failure: The ABS system does not work, and it is related to the failure of the wheel speed sensor, the hydraulic control unit or the ABS electronic control unit. Related to abnormal work.
Processing method:
(1) The wheel speed sensor is arranged on the wheel and is easily contaminated by mud and mud. The sensor is covered with a large amount of mud, which will affect the transmission of the vehicle speed signal. The ABS computer cannot judge the vehicle speed signal and will alarm. At this time, clean the dirt on the sensor and adjust the gap between the sensor and the signal ring gear. If the wheel speed sensor is damaged, it can only be replaced.
(2) It is likely that the data in the control unit does not match or is incorrect. Readjust the data. This item requires the use of a dedicated testing computer.
(3) The ABS control unit (ECU) circuit board is faulty and needs to be replaced. However, the probability of this kind of failure is very small. In some cars, even the circuit board of the ABS control unit can still be repaired simply, such as the welding point falling off, etc.
Vacuum booster failure
Performance:
1. Poor braking performance or no brakes Effect.
2. From the appearance, it can be seen that there is oil leakage at the external connection of the vacuum pump.
3. The brake pedal returns slowly or does not return.
4. An obvious abnormal sound can be heard after depressing the brake pedal.
5. When braking, the direction deviates or vibrates.
6. The brake pedal feels soft when you step on it.
7. If there is a fault in the vacuum assist braking system, a fault code will usually be reported and the fault warning light will light up.
Causes of failure:
1. The vacuum booster pipe joint is loose or the vacuum hose is leaking.
2. The one-way valve of the vacuum booster is damaged.
3. The vacuum booster is stuck inside.
4. The vacuum booster diaphragm is leaking.
Treatment method:
1. Replace the battery circuit and controller.
2. Replace the vacuum pump motor or electronic delay module.
3. Replace the pressure switch or pressure switch circuit.
4. Reconnect the ground wire in the power socket.
5. Replace the vacuum pump sealing ring. 【Details>>】
The brake drum spring is damaged or other faults cause the brake pads to fail to return, or improper brake adjustment causes the brake drum to heat up.
Brake drum failure
Performance: brake failure; when braking, the brake drumThere is an abnormal sound; the brake is stuck and does not return when the brake is stepped on; the brake drum is hot.
Causes of failure:
1. The brake drum is lacerated. The damage is mostly caused by the brake drum being made of poor material and not strong enough.
2. The damage to the brake drum is mainly due to the wear and deformation caused by the friction of the brake drum and the brake friction plate.
3. Frequently braking and accelerating the vehicle may cause loss of roundness and taper, resulting in early scrapping.
Treatment method: Disassemble the brake drum, clean the shoes and the brake drum. If the brake drum is found to have cracks during the cleaning inspection, it should be replaced. 【Details>>】
Brake master cylinder failure
Performance:
1. Brake master cylinder There is oil leakage at the connection between the pump and the vacuum booster or the limit screw.
2. After pressing the brake pedal to the bottom, the brakes are still poor or ineffective.
3. The brake pedal feels soft when you press it.
4. Derailed after braking.
5. The brakes suddenly failed.
6. The brake pedal does not return or returns slowly.
Causes of failure:
1. The oil quality is too dirty, causing the brake oil pipe to become clogged and the master cylinder pressure to be too high. Over time, the brakes will be ineffective and the oil pump will be easily damaged.
2. The oil quality is too low or deteriorates over time, which easily corrodes the sealing cup in the master pump. Over time, it will cause poor sealing, unable to seal oil and no oil pressure.
3. Frequent lack of oil or dry grinding will cause wear of the leather bowl.
4. Frequent use of the brakes will also be detrimental to the brakes.
Processing method: disassemble and clean, check whether the closing valve is damaged, and install it with some butter in good condition. If the damage is serious, replace it directly. 【Details>>】
Brake wheel cylinder failure
Performance:
1. Wheel cylinder There is oil leakage at the connection with the oil pipe, and the brake pedal will feel soft when you step on it.
2. After depressing the brake pedal, the steering wheel obviously tilts to one side. This situation is likely to be caused by uneven wear of the brake pads or failure of the wheel cylinder.
3. After stepping on the brake pedal, the pedal does not rise and there is no resistance, which is what we often say that the brake does not return.
Causes of failure:
1. The brake wheel cylinder is not a wearing part, and damage to the wheel cylinder is mostly due to quality problems.
2. Secondly, the damage to the wheel cylinder is also related to the failure to replace the brake disc in time. When the brake disc and brake pads are worn to the limit, continued use may cause damage to the wheel cylinder.
3. The oil quality is too low or deteriorates over a long period of time, which easily corrodes the sealing cup in the master pump. Over time, it will cause poor sealing, unable to seal oil and no oil pressure, which will lead to the failure of the oil pump. damage.
Processing method:
1. Prepare the diesel oil and pour itInside the brake cylinder, use an unnecessary toothbrush to scrub the inside of the brake cylinder. After scrubbing, use 2,000 grit sandpaper to polish the rust on the brake pump. After polishing, wipe the brake pump clean and install it back in the middle of the car tire. Just remove the hub.
2. A severely damaged brake cylinder can be directly replaced with a new one.
Oil leakage occurs at the connection between the brake master cylinder and the vacuum booster or the limit screw, the brake is poor or fails after the brake pedal is pressed to the bottom, the brake pedal feels soft when the brake pedal is pressed, the brakes deviate after braking, and the brakes Sudden failure, brake pedal does not return or returns slowly.
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