When the brake pedal wastes more than it should, after pumping (More continuous pressing of the brake pedal) the brake pedal start grabbing before and is harder to press, so it most likely has air in the brake system. Brake air removing is required.
This problem is most commonly occurred after the replacement of brake plates or after other brake repairs. There is a possibility that it’s in the middle of the brake damage. Then it’s needed to first remove the damage, because the problem after some time will occur again. And only then try to remove air from brakes.
For this job you will need two people. One who will pump the brake pedal, and the other who will empty the air from the air system near the cylinder that is located in the inner side of the wheel. Because the air after a longer use of the brake pedal comes to the brake cylinder.
So someone sits at the wheel and presses the brake pedal until he feels that it’s sturdy, and than just holds the brake in. So because the first person has the brake in, the second person unscrews the screw that the casing is recommended putting on, so that the oil doesn’t go everywhere. If we notice while the oil is spilling that there are bubbles there, then the air is coming out too. After the oil has stopped leaking, you need to screw the screw, and the brake pedal is pressed in while the oil is leaking (as the oil was leaking the brake pedal was being pressed on). The brake pedal must not be released until the screwing of the screw, because the air will go back in. Repeat this process all the way until there isn’t any more bubbles in the oil.
Then go onto another wheel and repeat the process. Do that for all four brake cylinders. If the screw can’t be untied like in my case. Then in the same way you can remove it. That the oil spills in the nearest cylinder. The air must be removed as close to the brake cylinder as possible.
Oil manufacturers say that the oil should be changed every 2 years. Since this is a closed system and there are no atmospheric influences and additional contamination, the oil can lose its property only due to high temperatures. Practice has shown that it is not necessary to change the brake oil if it is of a quality manufacturer.
Oils marked DOT3 .., DOT4 .. should not be mixed with DOT 5 .. because they are glycol-based and the others are silicone oils.
Be sure to add brake oil and check the system for oil leaks, although the oil level may drop due to wear and tear, so the brake piston leaks more.