How to Detect Car Brake Switch? How to check the brakes of the car

Hello, happy with your question.

1. The quality of the four-wire brake light switch needs to use a multimeter.

to test it out.

2. The multimeter is adjusted to the diode.

Measure the gear. Measure their pins with a red and black pen, respectively. If any two pins are on, they are normally closed contacts. The remaining two are normally open contacts.

Use the on-off gear of the watch to connect the watch pen to any two feet of the button switch, and press the button to see if it is open. In fact, it is a group of contacts, four pins are shorted in a group of two or two, find these two groups to take one of the pins in each group, test with the resistance file or on-off file of the multimeter, the resistance value is very small after pressing, and the infinity is infinite after release, as a good switch, if the ** measurement should have obvious resistance changes, but the open-circuit resistance may be relatively small, related to the external circuit.

3. There are four wires for the car brake light switch, one is a 12-volt power supply, and the other two are to the ABS system.

ECU, automatic transmission.

The ECU brake signal line, the other is the rear brake indicator. Some high-end models ABS shares a wire with the automatic transmission, and a brake signal line to the electronically controlled suspension is added. Therefore, several wires on the brake light switch, except for a power cord, the other ones are to the control unit that needs the brake signal, and the rear brake indicator is controlled by the body light system.

Just look at the car manual.

Here's how to check the brakes:

1. Look at the appearance.

Method: Observe the appearance of the brake disc to see if there is more mud and dust, if your car is dusty, wash the car quickly. Note: Do not rinse the brake pads when the brake disc is hot, as this may cause the brake disc to deform.

2. Touch.

Method: Observe the brake pads, and touch the scratches on the brake disc with your hand, if there are more deep scratches, you should pay attention to it, whether it should be polished or replaced, you should go back to Taizhou Xinbao to find an after-sales maintenance technician to deal with. Note:

Be sure to pay attention to the temperature when touching the brake pads, as a few heavy brakes may make the brake pads hot.

3. Pinch thickness.

Method: Check the wear of the brake pads, the wear of the brake disc should be within the range specified by the manufacturer, compare it by hand, if the wear is large, you should see if it needs to be replaced according to the inspection results. Compare whether the brake discs of the four wheels wear evenly.

Note: You should still be careful about the temperature of the brake disc so as not to get burned.

4. Check the liquid level.

Method: Check the height of the brake fluid, unscrew the brake fluid pot, the liquid level should be between the two scales, too much, too little will affect the braking force, to the right one. CAUTION: Prevent water, gasoline and some solid debris from falling into the brake fluid pot, which can cause a loss of braking power.

5. Look at the meter.

When the alarm light of the dashboard braking system is on, it means that there is a problem with the braking system, and then the system needs to be checked.

Terminology related to automotive braking

The braking rate of the whole vehicle is the percentage of the sum of the braking force and the weight of the whole vehicle. For example, if the braking force of the whole vehicle is 800N and the weight of the whole vehicle is 1000 kg, then the braking rate of the whole vehicle is 800 1000 percentage, that is. According to the technical conditions for the safe operation of the vehicle, the braking of the no-load vehicle should reach 60%.

Axle braking rate, axle braking rate, is the percentage of axle braking force and axle load. According to the requirements of the technical conditions for the safe operation of the car, the braking rate of the front axle should reach more than 60%, and the rear axle has several standards, and the rear axle of passenger cars and other cars with a total mass of less than 3500kg should reach 20%. 55% for trailers and 50% for other cars.

The unbalance rate is the ratio of the maximum value of the difference between the braking force of the left and right wheels measured at the same time in the whole process of braking force growth and the ratio of the greater of the maximum braking force of the left and right wheels of the axle measured in the whole process. This concept is complex and difficult to understand if you are not professional. It's good that you know there's such a thing.

The sum of the parking braking rate and parking braking force should be greater than 20% of the weight of the car in the test state.

The brakes are inspected by special mechanical equipment, the active wheels and the passive wheels are separated from the equipment, the active wheels should be driven by the engine and then the brakes are tested by the staff, and the handbrakes and passive wheels have special machinery to rotate the wheels, which are also tested by the staff in the brakes.

Brake deviation check the front brake cylinder and brake pads, the cylinder is not synchronized will produce deviation, followed by uneven tire wear and positioning problems.

Acceleration and hard braking.

When the vehicle is lifted to a certain height, check the wear of the brake cylinder and brake pads and brake discs! ~

Brake test by staff The driving wheels should be driven by the engine, and then the brakes will be tested by the staff.

Generally, the brake detection is divided into three steps: the first step is the front wheel brake, the second step is the rear wheel brake, and the last step is the handbrake, and the four-wheel drive vehicle has a four-wheel test board.

How to self-check the braking system before the annual inspection.

Front and rear brakes.

You can first drive a small speed for a distance to brake, the tire deviates which side is basically that side of the braking force is not enough, at this time should check whether the brake pad has not been changed for too long, whether the brake fluid is water-based, the drum brake vehicle is not tight or has been grinded almost, how long to change the brake pads, in addition to often running long distances to save brakes, the most important thing is whether the driving mode is appropriate, such as the amount of driving in advance, if you can grasp it well, you will find that many times there is no need to step on the brakes.

Generally speaking, a pair of brake pads is no problem with 100,000 kilometers, and if used well, it can even reach 150,000 kilometers. Since every driver applies the brakes differently, it can be difficult to determine how often the brake pads need to be replaced. The only way to do this is to check the level of wear and tear of the brake pads during a routine inspection, and if they reach a critical point, they need to be replaced immediately.

Oil leakage from brake calipers and brake pumps is also the cause of unsatisfactory braking effect, which can be easily detected.

Check the brake fluid The first step in the self-test of the automobile brake system is to check the amount of fluid buried in the automobile brake fluid. Make sure that the amount of brake fluid is stored between the upper and lower lines of the reservoir. If there is a lack of brake fluid, the same kind and brand of brake fluid should be added, and other types of brake fluid or alcohol substitutes should not be added.

Check the brake pedal The inspection of the brake pedal of the car is judged by the eyes and the "foot feeling", and the so-called brake pedal "foot feeling" is judged by the driver's foot.

Let me tell you about the process of checking the brake system.

First of all, when applying the brakes, one foot pedal to the end. At this point, there should be no brake fluid.

Finish. If you press the brake pedal, the pedal keeps sinking and slowly goes to the end. At this time, it should be a leak of brake fluid.

Secondly, when the brakes are applied, the pedals are stiff。And it can't be stepped on. At this time, it should be a failure of the brake assist system or a vacuum tube.

Dilapidation. Again, when the brakes are applied, it is obvious that the pedal is larger than the original working stroke, that is, the pedal is deeper than the original pedal。At this point, it should be brake pads.

If the gap is too large, it should be that the brake pads are almost finished. It's time to change the brake pads.

Also, when you apply the brakes, you feel that the pedal is softer than usual, and there should be air in the pipe at this time.

In addition, if the brake fluid (open the lid of the oil can) has emulsification, it means that the brake system has entered the water. The effect is definitely poor.

Finally, drive at a speed of 30kmh with both hands on your handsSteering wheelHowever, if you do not use force, the direction deviates when you press the brakes, indicating that there is a problem with the braking of individual wheels.

In general, many car instruments have indicators to respond to brake failures. For example, if the brake fluid is less, the brake alarm will alarm, and if the ABS is faulty, the ABS light will be on.

The air brake reacts differently. For example, when you apply the brakes, you can clearly hear an air leak sound, indicating that the system is leaking. There is also a significant lack of air intake when the brakes are applied, and it is estimated that there is a problem with the master cylinder.

The static check includes the following entries and operations:

1. Open the engine compartment cover to check the brake fluid.

The amount of fluid level, the visible amount of brake fluid should be between the minimum and maximum marking lines;

2. Check whether the vacuum booster and vacuum tube are damaged;

3. Open the door, do not start the vehicle when the vehicle is powered on, and press the brake pedal.

Feel the change in pedal force, and the vacuum pump can be heard in vehicles equipped with EVP after the third braking.

the sound of work;

4. Press the brake pedal while confirming that the rear brake brake light is lit normally;

If all the above static tests are passed, the following dynamic tests can be carried out, otherwise maintenance is required to ensure that the static tests pass.

Dynamic testing includes the following:

1. Parking ability test, drive the vehicle to the ramp to start or tighten the handbrake.

Observe whether the vehicle remains stationary;

2. Emergency braking from 30 km/h on high attached roads.

When the vehicle stops, observe whether the ABS is working properly and observe if the vehicle is out of lane.

In short, the brakes are no joke. Every time the old driver starts, he will click on the brake to prevent the brake from failing.

It depends on how much you know about the car, if you know the car very well, then when checking the brake system, you must pay attention to the details, do not bring unnecessary trouble to yourself. And in the process of inspection, if it is found that the parts are aging, then they must be replaced in time. But if you don't know anything about cars, then when you check the brake system, you must send it to a professional repair shop for maintenance, because those professionals know more than us, and can also help you solve some safety hazards.

First replace the brake pads, then check the degree of wear, and then clean the oil stains on the surface.

The first thing to do is to check the thickness of the brake pads or brake shoes regularly. When it is found that its thickness is close to or less than the minimum thickness specified by the manufacturer, it should be replaced immediately. While checking the brake pads, it is also necessary to check the wear of the brake disc or brake drum, such as dents on the contact surface, the disc or drum should be timely to ensure the contact area with the brake pads and improve the braking force.

For cars with oil brakes, check the fluid level of the brake fluid before leaving the car. If you notice a drop in the oil level, immediately check the brake fluid circuit for leaks. Brake fluid will fail after a long time due to the absorption of moisture in the air.

Change the brake fluid regularly according to the manufacturer's regulations.

If we find that the thickness is less than the specified thickness, then we can replace it in time. Then there will be a screeching sound when braking, so the brake pads should be replaced in time. If the fluid level of the brake fluid drops, it should also be replaced in time.

After the car has traveled 20,000 kilometers, you must maintain the car, maintain the engine, and change the brake pads.

Today, I would like to introduce to you the knowledge of automobiles. Many friends have encountered such a problem, the brake is easy to break, resulting in the aftermath of the accident search scene. Then, let's learn how to check the brakes of a car's gear breaker.

Introduction to the inspection method of automobile brakesMethod: Look at the thickness: The thickness of a new brake pad is generally around the limit, and it will gradually become thinner with the continuous friction in use.

Professional and technical personnel suggest that when the naked eye sees that the thickness of the brake pads is only about 1 3 of the original thickness, the owner should increase the frequency of self-inspection, and prepare for replacement at any time. Of course, due to the design of the wheels, some models do not have the conditions for visual inspection, and the tires need to be disassembled to complete. Introduction to the inspection method of automobile brake method 2:

Listen to the sound: if there is iron rubber iron. silk noise, at which point the brake pads must be replaced immediately.

Because the limit marks on both sides of the brake pads have rubbed directly against the brake disc, proving that the brake pads have exceeded the limit. In this case, when replacing the brake pads, it is necessary to cooperate with the inspection of the brake disc. When this sound occurs, the brake disc is usually damaged.

Well, that's the end of today's introduction. As we can see from the article above, we must check our brakes regularly and check them regularly according to the method. I hope today's introduction will be helpful to you.

The car handbrake is a kind of auxiliary braking system, which is mainly set up to prevent the vehicle from rolling on its own when parking. However, the handbrake is not a "one-size-fits-all insurance", and its effectiveness will decrease with the number of uses. Therefore, the owner regularly inspects and maintains the handbrake.

The specific method is as follows:

1.Determine the position of the handbrake handle

To check whether the handbrake is normal, you can first check the handle position of the car handbrake. Normally, when the handle is lifted to 70% of the full stroke, the handbrake braking system should be in the normal braking position, so before checking the braking force of the handbrake, you should first find out this 70% working point, which can be determined by counting the ratchet sound.

2.Check if the handbrake is working

Drive the car to a slope with a large slope and a good road condition (preferably an asphalt road), press the brakes, put the gear position in neutral gear (or hang it in N gear if it is an automatic transmission), and pull the handbrake handle to the position of the working point just determined. Then slowly release the brake pedal, if the car does not slip, it means that the handbrake is working well. This inspection should be done once on the uphill slope and once on the downhill slope.

3.How to adjust the handbrake

In the above inspection, if it is found that the braking efficiency or sensitivity of the handbrake is not ideal, it can usually be solved by adjusting the operating copper cable of the handbrake. At the bottom of the handbrake lever at the junction with the copper cable (generally covered by interior parts) there is an adjustable'The compensation mechanism, loosen the lock nut with a wrench, and the length of the brake copper cable can be stretched. However, the adjustment mechanism of some cars is located at the bottom of the car, and if it is inconvenient to adjust, it should be handled by professional maintenance personnel.

Notes:

Many people think that if the braking system fails, they can pull the handbrake to slow down, but this practice is wrong. Because the handbrake mechanism is not precise, the braking force on the left and right sides is unevenly distributed, and it is easy to lock the rear wheel of one side when pulling the handbrake at high speed, and the side slip occurs, which is very dangerous. The correct way to do this is to slow down by downshifting, and only pull the handbrake to stop the car when the speed is reduced.