How to properly check and change the brake fluid!

The ability of a car to brake is much more important than the ability to drive. Therefore, brake fluid is by far the most important working fluid in every vehicle. If it is missing or something is wrong with it, the safety of the car and all other road users is at risk. Read everything you need to know about brake fluid in this article.

Hydraulic power transmission and boost

Brake system , except for the parking brake, hydraulically actuated in family cars which means that braking force is transmitted through fluids . Fluids have the property of being evenly distributed within the tubing and recipient system and cannot be compressed. The force applied, for example, when pressing the brake pedal, immediately affects the entire system.

As an alternative there are air brake systems as well as hybrid systems in which hydraulic and pneumatic components work together . These systems can be found in trucks и buses . That's why these cars hiss when they stop at traffic lights. Both systems are tuned to each other. Gases can compress, reducing and slowing down its power transmission. This is the main difference between hydraulic and pneumatic systems.

Family cars are equipped exclusively with hydraulic brake systems. . Only the parking brake is actuated by a cable. Gases in the brake lines can have fatal consequences: they can lead to complete failure of the brake system. , as a result of which the driver will be in a vacuum. He can do nothing to prevent the car from crashing into an obstacle.

How does gas get into brake fluid?

Gas can enter the brake fluid in two ways: braking can cause condensate to boil, resulting in vapor bubbles . In addition, air can enter the brake system through leaks. This is rare, but can happen with older brake systems or with the wrong brake fluid.

The presence of water in the brake fluid is especially critical. . This liquid has certain properties and tasks:

– Durability and reliability at high and low temperatures – Reliable power transmission – No flocculation – No chemical reaction with any contact substance

Main enemy: water

Commercially available brake fluid is able to meet these requirements, although not without side effects. One such effect is that the liquid is hygroscopic, i.e. attracts water . Just as a block of salt absorbs condensation from the air, brake fluid gradually attracts water.

К счастью, clearly visible accumulation of water . Fresh brake fluid is clear and golden yellow. Old and contaminated brake fluid is green and cloudy. Attention: when the brake fluid has this color, the point of safe replacement has been exceeded. Immediate action required!

Always completely changing

Before replacing, check the brake fluid level . If it is too low, the system is obviously losing this important hydraulic fluid. Before pouring new brake fluid, find and repair the leak.

Be careful: simply adding new brake fluid is wrong and dangerous. Fresh brake fluid will be immediately contaminated. Moreover, the leak is not eliminated, and the brake system will fail sooner or later.

Therefore, the brake fluid is always completely changed. . It either drains or drains through the wheel brake cylinder vent screw.

Professional auto repair shops additionally blow out the brake system with compressed air to free it from fluid residue.
 

Don't forget to ventilate

Fresh brake fluid just does not top up . The entire brake system must be vented so that it contains only liquid and no air.

The easiest way is to put an assistant behind the wheel . Start with the wheel brake cylinder furthest from the brake pedal. For right hand drive vehicles, such as those in the British Isles, this is the left rear wheel. Its vent screw is open. The assistant pumps the brake pedal until the brake fluid runs out. Now the vent screw is quickly tightened and the procedure is repeated on all wheels. In this case, it is necessary to check the fluid level.

Compliance with maintenance schedules

By law, brake fluid in a car must be changed every two years. . This is covered by the MOT inspection, so old brake fluid must be identified at the inspection. During the inspection, however, it is not the composition of the brake fluid that is checked, but only the functioning and tightness of the brake system.
Therefore, the condition of the brake fluid is very important when buying a used car. . It may have been sitting still for a very long time or the previous owner didn't mind the service intervals.

Our advice: there are test strips in the accessories store to measure the amount of water in the brake fluid. Nevertheless , we recommend change oil as well as brake fluid when buying a used car.

Do not pour old brake fluid down the drain, but treat it like chemical waste . It can be poured into a container of new oil and handed over at the point of purchase. The supplier will take care of their disposal. Alternatively, you can send it to an online store free of charge or take it to a waste disposal point.

Brake fluid must not be mixed

Brake fluid must not be added indiscriminately . Always use the same brake fluid for replacement or leveling: the version prescribed by the manufacturer. Suitable liquid can be determined by DOT code on the package.

In Europe, this is usually DOT 1–4. DOT 5 is mainly used for American vehicles. It is important to act on these data.

Improper brake fluid can affect the components of the brake system, which can lead to leakage and contamination of the system. Both can lead to a dangerous traffic situation if the brake fails.

Remember Brand Quality

The brake is the most important part of a car. Its components must always be first class brand quality . This also applies to brake fluid. Nameless products from unknown sources can be counterfeit and low quality, which poses an incalculable risk. Brakes require top-notch material, even if it costs more. The safety is worth it.