Brake Fluid

Brake Fluid

Brake fluid is a type of hydraulic and EP oil that must perform the important task of stopping the wheels of a vehicle properly, and its standards are subject to the US Department of Transportation (DOT).
Brake fluid is a hydroxide oil with low viscosity and hydraulics to withstand the heat of the wheel disc well.
Types of brake fluid:
Out of date : DOT 1 & DOT 2
FMVSS116 Car safety standard Federal Republic of America Quality brake fluid completely to dry boiling point, wet boiling point Wet EBRP DOT 3 & DOT 4 & DOT 5.1


Brake fluid is a type of hydraulic fluid used in hydraulic brake and hydraulic clutch applications in automobiles, motorcycles, light trucks, and some bicycles. It is used to transfer force into pressure, and to amplify braking force. It works because liquids are not appreciably compressible.

Most brake fluids used today are glycol-ether based , but mineral oil ( Liquide Hydraulique Minéral (LHM)) and silicone-based (DOT 5) fluids are also available.


The Federal Motor Vehicle Safety Standards (FMVSS) under FMVSS Standard No. 116 defines grades DOT 3, DOT 4, DOT 5 and DOT 5.1, where DOT refers to the US Department of Transportation. These are widely used in other countries. Their classifications broadly reflect the SAE's specifications, but with local details — Alaska and the Azores for example, have different normal temperature and humidity ranges to consider. DOT 3 is equivalent to SAE J1703 and ISO class 3, DOT 4 to SAE J1704 and ISO class 4, etc.

All approved fluids must be colorless or amber to be acceptable for street use in the U.S, except for DOT 5 silicone, which must be purple.

BF 4

You, as our dear customer and as our audience, can use our products whenever you like. You can do the process of ordering your desired product according to your opinion and enjoy driving quietly and calmly. Also, our team will contact you immediately and will provide you with the necessary advice regarding any brake fluid.
What happens if your brake fluid is low?
Soft, Bouncy, or Spongy Brake Pedal

Low brake fluid will cause air to fill the gaps in your brake line—leading to soft brakes. Spongy brake pedals can be both terrifying and dangerous—especially if you do not get them serviced at the first sign of an issue.
What are the signs of needing brake fluid?
Another way to tell if your brake fluid is low or needs to be replaced is if your brake pedal isn't responding like it used to. If your pedal feels firmer than usual, the fluid could be contaminated. If it feels easier or softer when you press the pedal down, this can mean that your fluid is getting low.
How long can brake fluid last?
In ideal conditions, an unopened bottle of brake fluid lasts about two years. It's best to use a new bottle of brake fluid every time you need it because the fluid attracts moisture as soon as it is opened. Once in your vehicle, brake fluid life is based on the application in which it's used.
When should brake fluid be changed?

A good rule to follow is to have your mechanic check your brakes and brake fluid during every oil change. They'll be able to give you the best feedback on how your brakes are working and if they need new fluid. Most drivers find they need to change their brake fluid every four to five years.



Brake fluids must have certain characteristics and meet certain quality standards for the braking system to work properly.


For reliable, consistent brake system operation, brake fluid must maintain a constant viscosity under a wide range of temperatures, including extreme cold. This is especially important in systems with an anti-lock braking system (ABS), traction control, and stability control (ESP), as these systems often use micro-valves and require very rapid activation.DOT 5.1 fluids are specified with low viscosity over a wide range of temperatures, although not all cars fitted with ABS or ESP specify DOT 5.1 brake fluid.For a faster reaction of the ABS and ESP systems, DOT 4 and DOT 5.1 brake fluids exist with low viscosity meeting the maximum 750 mm2/s viscosity at -40 °C°F requirement of ISO 4925 class 6. These are often named DOT 4+ or Super DOT 4 and DOT 5.1 ESP.

Boiling point

Brake fluid is subjected to very high temperatures, especially in the wheel cylinders of drum brakes and disk brake calipers. It must have a high boiling point to avoid vaporizing in the lines. This vaporization creates a problem because vapor is highly compressible relative to liquid, and therefore negates the hydraulic transfer of braking force - so the brakes will fail to stop the vehicle.

Quality standards refer to a brake fluid's "dry" and "wet" boiling points. The wet boiling point, which is usually much lower (although above most normal service temperatures), refers to the fluid's boiling point after absorbing a certain amount of moisture. This is several (single digit) percent, varying from formulation to formulation. Glycol-ether (DOT 3, 4, and 5.1) brake fluids are hygroscopic (water absorbing), which means they absorb moisture from the atmosphere under normal humidity levels. Non-hygroscopic fluids (e.g. silicone/DOT 5 and mineral oil based formulations), are hydrophobic, and can maintain an acceptable boiling point over the fluid's service life.

Silicone based fluid is more compressible than glycol based fluid, leading to brakes with a spongy feeling. It can potentially suffer phase separation/water pooling and freezing/boiling in the system over time - the main reason single phase hygroscopic fluids are used.

Characteristics of common braking fluids

Dry boiling point Wet boiling point[a] Viscosity at -40 °C°F Viscosity at 100 °C (212 °F) Primary constituent
DOT 2 190 °C (374 °F) 140 °C (284 °F) ? ? castor oil/alcohol
DOT 3 205 °C (401 °F) 140 °C (284 °F) ≤ 1500 mm2/s ≥ 1.5 mm2/s glycol ether
DOT 4 230 °C (446 °F) 155 °C (311 °F) ≤ 1800 mm2/s ≥ 1.5 mm2/s glycol ether/borate ester
DOT 4+ 230 °C (446 °F) 155 °C (311 °F) ≤ 750 mm2/s ≥ 1.5 mm2/s glycol ether/borate ester
LHM+ 249 °C (480 °F) 249 °C (480 °F) ≤ 1200 mm2/s[16] ≥ 6.5 mm2/s mineral oil
DOT 5 260 °C (500 °F) 180 °C (356 °F) ≤ 900 mm2/s ≥ 1.5 mm2/s silicone
DOT 5.1 260 °C (500 °F) 180 °C (356 °F) ≤ 900 mm2/s ≥ 1.5 mm2/s glycol ether/borate ester
DOT 5.1 ESP 260 °C (500 °F) 180 °C (356 °F) ≤ 750 mm2/s ≥ 1.5 mm2/s glycol ether/borate ester
ISO 4925 Class 3 205 °C (401 °F) 140 °C (284 °F) ≤ 1500 mm2/s ≥ 1.5 mm2/s
ISO 4925 Class 4 230 °C (446 °F) 155 °C (311 °F) ≤ 1500 mm2/s ≥ 1.5 mm2/s
ISO 4925 Class 5-1 260 °C (500 °F) 180 °C (356 °F) ≤ 900 mm2/s ≥ 1.5 mm2/s
ISO 4925 Class 6 250 °C (482 °F) 165 °C (329 °F) ≤ 750 mm2/s ≥ 1.5 mm2/s
ISO 4925 Class 7 260 °C (500 °F) 180 °C (356 °F) ≤ 750 mm2/s ≥ 1.5 mm2/s

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If you accidentally put ATF into a CTV the rate at which it will die is directly related to the ratio of fluids. In a CVT transmission, it is impossible to drain all of the CVT fluid. If you have accidentally added ATF, your transmission would then contain a mixture of ATF and CVT fluids. Your CVT transmission will still function for a period of time since it is a mixture of both fluids and there will still be enough friction for the CVT transmission to work for a while. Eventually, however, permanent damage will occur and you have to rebuild your transmission.