What does brake fluid do? Why should I change my brake fluid? What are the commonly used brake fluid

Brake fluid plays a transmission role in the braking system of an automobile (Figure 1-93). Press the brake pedal with your foot, with the assistance of vacuum booster, push the brake master cylinder, the brake master cylinder pushes the brake fluid, and the power under your feet is transmitted to the brake cylinder to which the four wheels belong through the brake fluid, and the brake cylinder pushes the brake pad, and the brake pad squeezes the brake disc to form a braking force.

Figure 1-93 Automobile braking system.

Since the bowl and piston in the brake cylinder wear out after a long period of use, causing the brake fluid to become cloudy, it is necessary to replace it with the best treatment method. If you replace the unqualified or normal quality brake fluid, it will corrode the leather bowl of the brake cylinder, and it will also have an impact on the braking effect, so if the brake fluid is missing, it is best to buy the brake fluid produced by the regular manufacturer, and do not spend a lot of money in order to save a small amount of money. Brake fluid produced by regular manufacturers not only works well to use, but also can extend the service life of the braking system (Figure 1-94).

There are two commonly used brake fluids: dot3 and dot4. DOT is the nominal designation specified in the U.S. automotive safety standard, and the higher the number, the higher the level (Figure 1-95).

<>Figure 1-94 Brake fluid produced by a regular manufacturer.

Figure 1-95 DOT3 and DOT4 brake fluids.

The difference between dot3 and dot4 is mainly due to the difference in boiling points, and the performance indicators of the two are shown in Table 1-8.

Table 1-8 Performance metrics of dot3 and dot4

DOT3 and DOT4 brake fluids are non-mineral oils, which are based on polyethylene glycol and ethylene glycol and ethylene glycol derivatives-based alcohol ether type synthetic brake fluids, and then blended with lubricants, thinners, rust inhibitors, rubber inhibitors, etc., and are also the most commonly used brake fluids for automobiles in various countries. This commonly used brake fluid is highly hygroscopic. Although the braking system cannot enter the water, the brake fluid will absorb a considerable amount of water after a period of use.

The more water in the brake fluid, the lower the boiling point. In order to ensure driving safety, the brake fluid should be changed regularly, usually every 2 years. Because brake fluid absorbs water, don't use brake fluid that has been opened for years.

At present, there are also DOT5 brake fluids on the market, but its hardness is too high and the water absorption is also very strong, and it is not suitable for ordinary civilian cars.

No matter which automobile manufacturer manufactures a vehicle, there will be clear regulations on the brake fluid required for the car, and from the perspective of market penetration, the vast majority of passenger cars currently available on the market use DOT4 brake fluid.

The function of brake fluid is to transfer energy, dissipate heat, prevent corrosion, rust and lubricate.

Brake fluid is mainly used in the braking system, through the hydraulic way to push the piston of the brake cylinder for braking, the long-term brake fluid has dot4 and dot5 long-term use of the brake fluid contains impurities, water content exceeds the standard, the replacement of brake fluid is mainly to reduce the braking time in driving, shorten the braking distance.

The function of the automobile brake fluid: the brake fluid is increased by the main brake cylinder through the liquid pressure, so that the piston on the sub-cylinder on the four wheels is ejected under the action of the sealed leather bowl, and the principle of lever is used to act on the brake disc and brake pad. Brake fluid, also known as brake fluid, comes in three types.

When purchasing, you should choose a reliable manufacturer, and the higher the level, the better. Its braking working pressure is generally 2MPa, and the high can reach 4 5MPa. All liquids are incompressible, and when the liquid is under pressure in a sealed container or in a line filled with liquid, the pressure is transmitted quickly and evenly to all parts of the liquid.

Hydraulic brakes work using this principle.

Brake fluid, also known as brake fluid, is a functional liquid that transmits pressure in the vehicle braking system and enables the braking system on the wheels to achieve braking action, and its main role is to transmit energy, heat dissipation, anti-corrosion, anti-rust and lubrication.

The performance requirements for brake fluid are:

1. Good viscosity and temperature, low freezing point, and good fluidity at low temperature.

2. The boiling point is high, and there is no gas resistance at high temperature.

3. The quality changes little during use, and does not cause corrosion and deterioration of metal parts and rubber parts.

Extended Information: Precautions for Buying Brake Fluid:

1. Look at the viscosity and color of the product, the brake fluid is too thin to use, there is no color, transparent can not be used (generally the color of the qualified brake fluid is light yellow or dark yellow), the qualified brake fluid is obviously more viscous than water, it looks like diluted honey, and the diffusion speed is slow when poured on the glass plate.

2. The viscosity of inferior brake fluid is as thin as water, and the diffusion speed of pouring a small amount on the glass plate is fast, and you can feel that there is no consistency when you dip your fingers.

3. Comparison, cost decision, quality determination. The raw material of qualified brake fluid is mainly the basic raw material of petroleum processing - ethylene oxide, which is polymerized from ethylene oxide into polyethylene glycol monoether. This results in a high material cost for qualified brake fluid.

Brake fluid is a liquid medium that transmits braking pressure in a hydraulic braking system and is used in vehicles with hydraulic braking systems.

Brake fluid, also known as brake fluid or force oil, its English name is brake fluid, is an indispensable part of braking system braking, and in the braking system, it is used as a force transmission medium, because the liquid can not be compressed, so the pressure output from the master cylinder will be directly transmitted to the sub-cylinder through the brake fluid.

China's current brake fluid standard GB12981-2012 "Motor Vehicle Brake Fluid" is a mandatory standard, with a total of 15 technical index requirements, namely appearance, equilibrium reflux boiling point, wet equilibrium reflux boiling point, kinematic viscosity (100, -40), pH value, liquid stability, corrosivity;

Low temperature fluidity and appearance, evaporation performance, water holding capacity, liquid compatibility, oxidation resistance, rubber compatibility, stroke simulation performance, and rust resistance.

Precautions for using brake fluid:

1. Regular replacement: After a period of use, the performance indicators will be reduced due to moisture absorption, chemical changes and other reasons, which will affect driving safety, so the brake fluid should be replaced regularly in use;

2. Do not mix the brake fluid, due to the different raw materials, additives and production processes used in different types of products, turbidity or precipitation will occur after mixing, which will not only reduce the performance of the original brake fluid, but also cause serious consequences of brake failure due to the deposition of particles blocking the pipeline.

The above content reference

There are 3 types of brake fluids, which are:

Ricinol type: blended with refined castor oil and low-carbon alcohol;

Synthetic: made of ether, alcohol and ester mixed with lubrication, anti-oxidation, anti-rust and anti-rubber swelling additives;

Mineral oil type: made by adding a thickener to a refined light diesel oil fraction.

Brake fluid is the liquid medium that transmits braking pressure in hydraulic braking systems, and is used in vehicles that use hydraulic braking systems. Brake fluid, also known as brake fluid or force oil, its English name is brake fluid, which is an indispensable part of braking system braking, and in the braking system, it is used as a force transmission medium, because the liquid cannot be compressed, so the pressure output from the master cylinder will be directly transmitted to the sub-cylinder through the brake fluid.

Brake fluid is brake fluid, which is a functional liquid (medium) used to stop the wheel from turning, which not only plays the role of transferring energy, but also has the effect of anti-corrosion, anti-rust and lubrication, which can be said to be an indispensable part of the brake system.

Three kinds. They are castor oil-alcohol type, synthetic type, and mineral oil type.

1. Castor oil-alcohol type: It is made of 45%-55% refined castor oil and 55%-45% low carbon alcohol (ethanol or butanol), and is precipitated to obtain a colorless or light yellow clear and transparent liquid, that is, alcohol-type automobile brake fluid. Castor oil plus ethanol is alcohol type No. 1, and castor oil plus butanol is alcohol type No. 3.

The raw materials of alcohol-type brake fluid are easy to obtain, the synthesis process is simple, and the product has good lubricity; The disadvantage is that the boiling point is low and the properties are unstable at low temperatures. Ethanol vapor appears above 45 °C in alcohol type 1, resulting in gas resistance; At -25 °C, castor oil precipitates as a milky white gelatinous substance, and increases with the decrease of temperature, blocking the braking system and making the braking system fail heavily.

2. Synthetic type: made of ether, alcohol, ester and other additives mixed with lubrication, anti-oxidation, anti-rust, anti-rubber swelling and other additives.

3. Mineral oil type: made by adding thickeners and other additives to the refined light diesel oil fraction.

The normal replacement cycle of brake fluid is 2 years or 40,000km first, the dry climate in the north can be appropriately extended for one and a half years, but the air humidity in the south is high, and it should be replaced in time according to the cycle to ensure the safety of the car.

It should have been replaced in about two years. It can greatly improve the safety during driving, and it can also reduce the wear and tear of the machine.

Summary. Pro, the steps of changing the brake fluid: 1. Put the vehicle in a state of flame-off, open the lid of the brake fluid, and use a syringe to pull out all the brake fluid inside until it reaches the bottom of the tank; 2. Pour the new brake fluid into the fuel tank (1 to 2L), and how many liters to fill depends on the capacity of the fuel tank; 3. Lift the bottom of the car with a jack, then find the oil drain screw of the brake cylinder, and remove the dust cap on the oil drain buckle; 4. Use a wrench to loosen the oil drain screw, put the rubber tube on it, and connect the other end to the oil drain bottle.

Pro, the steps of brake fluid replacement: 1. Put the vehicle in a state of flame-off, and open the lid of the brake fluid, and use the injection injector to extract all the brake fluid inside until the head of the finger is empty to the bottom of the tank; 2. Pour the new brake fluid into the fuel tank (1 to 2L), and how many liters to fill depends on the capacity of the fuel tank; 3. Use a jack to raise the bottom of the car to a high level, then find the oil drain screw of the brake cylinder, and remove the dust cap on the oil drain buckle; 4. Use a wrench to loosen the oil drain screw, put the rubber tube on it, and connect the other end to the oil drain bottle.

5. Start to step on the brakes, you need to pay attention to the color of the brake fluid in the rubber tube, if the color is still relatively dark, it proves that the old brake fluid has not been discharged, if the color is relatively light, it means that the tire has completed the oil change, stop stepping on the brake and install the screws and dust caps back slowly, and the other three tires are also operated in this way; 6. It is necessary to observe the position of the liquid level of the brake fluid, and if it is lower than the minimum scale line, it is also necessary to replenish the brake fluid.

The role of brake fluid: 1. It can effectively lubricate the moving parts of the brake system and prolong the service life of the brake cylinder and leather bowl; 2. Anti-corrosion and anti-rust effect, no corrosiveness to metal and non-metallic materials of the brake system; 3. Adapt to various environments to ensure the flexible transmission of braking force under high temperature, severe cold, high speed, humid heat and other working conditions; 4. The role of energy transfer and heat dissipation.

The role of brake fluid:

1. It can effectively lubricate the moving parts of the brake system and prolong the service life of the brake cylinder and leather bowl;

2. Anti-corrosion and anti-rust effect, no corrosiveness to metal and non-metallic materials of the brake system;

3. Adapt to various environments to ensure the flexible transmission of braking force under high temperature, severe cold, high speed, humid heat and other working conditions;

4. The role of energy transfer and heat dissipation.

Brake fluid, also known as brake fluid, is a functional fluid used to transfer pressure in a car's hydraulic braking system and enable the wheel brakes to brake. It has the functions of energy transfer, heat dissipation, anti-corrosion, anti-rust, lubrication and so on. At present, the continuous improvement of the technical level of automobile engine, the improvement of road traffic conditions, the development of highways and the improvement of the structure of automobile braking system have put forward higher and higher requirements for the performance of brake fluid.

Automotive brake fluids are mainly composed of volatile and flammable organic solvents. Therefore, stay away from fire, pay attention to fire sources and moisture, and especially prevent the absorption and deterioration of rain, sunlight and moisture. Due to the different raw materials, additives and production processes used for different types of products, turbidity or precipitation can occur after mixing.

Not only does this drastically reduce the performance of the original brake fluid, but it can also lead to serious brake failures due to particle deposits clogging the pipes.

Photo by Pacific Automobile Network Q&A).

What is the role of brake fluid? Brake fluid, also known as brake fluid, is a functional liquid that transmits pressure in the vehicle braking system and enables the braking system on the wheels to realize braking action, and its main role is to transmit energy, heat dissipation, anti-corrosion, anti-rust and lubrication. The role of brake fluid is:

The brake fluid is pressurized by the brake main cylinder through the liquid pressure, so that the piston on the sub-cylinder on the four wheels will eject the piston under the action of the sealed leather bowl, and act on the brake disc and brake pad to realize the brake function. The characteristics of brake fluid are: 1. The freezing point is very low

It has good fluidity at low temperatures; 2. High boiling point: no gas resistance will be produced in the state of high temperature; 3. Small quality change: it will not cause the erosion of metal and rubber.

The replacement method of brake fluid is: 1. Place the vehicle on the trench or lift it with a lift; 2. Wipe the oil drain port, remove the dust cap, unscrew the oil port screw, press the brake pedal repeatedly, and tighten the oil drain screw after the oil is clear; 3. Add brake fluid. @2019