Malfunctions of the main brake cylinder, possible reasons and ways of their elimination

Each car should not only accelerate well, but also brake. This function is performed by pads, drums and many other elements. The serviceability of each of them is a guarantee of the safety of the driver and passengers. Each brake system has a master cylinder. Faults it, the design and the principle of work - later in this article.

Characteristic

This cylinder is the central element of the brake system. Its purpose is to convert the mechanical forces from the brake pedal to pressure. This element works thanks to liquid, under high pressure.

Device

All modern cars are equipped with a two-section master cylinder. If it is a front-wheel drive car, the first circuit combines the braking forces of the front right and rear left wheels. The second - the right rear and the front left. As for cars with rear-wheel drive, here the contours work differently. The first is responsible for the front wheels, and the second, respectively, for the rear wheels. Where is the master cylinder? This element is attached to the vacuum cap. Above the element is a plastic two-section tank with brake fluid (by the way, it is also poured into the clutch system, if it is driven by a hydraulic drive). In the tank are provided bypass and compensation holes. The tank itself serves to compensate the level of the liquid in case of its loss. This can be evaporation or leakage. There are level marks on it. Always watch him and keep it at maximum. Some cars have a liquid level sensor that goes to the main brake cylinder VAZ-2106. Malfunctions associated with its leakage will be displayed on the instrument panel in the form of an emergency lamp. Before to learn signs of malfunction of the main brake cylinder, we will consider its device and algorithm of work. This element consists of two successive pistons. The first one rests on the amplifier's stem, and the second one is in the free position. Since they work under high pressure, the body is made of metal, and rubber seals are used as seals. Also in the design there are return springs that return and hold both pistons in the initial position.

How does he work?

When the driver presses the brake pedal, the vacuum rod pushes the piston. When moving, it covers the hole in the cylinder (compensating). Pressure in the first, and then in the second circuit, significantly increases. The liquid begins to flow into the voids, which are formed due to the movement of the first and second pistons. The movement of the latter occurs until the maximum pressure necessary for the operation of the discs and pads develops in the circuit of the brake system. When the pedal is released, the piston takes its initial position under the action of the return spring. Passing through a special hole in the circuit, the level of pressure drops to atmospheric pressure. It happens very quickly. But even with the sharp release of the pedal, the vacuum in the working circuit is not formed, thanks to the presence of hydraulic fluid. It fills the entire space behind the piston with all the volume. With each new braking, the fluid flows smoothly and returns through the bypass hole into the plastic tank.

Emergency mode

It is worth noting the high reliability of the system. And even if there are malfunctions of the main brake cylinder (VAZ is not an exception), the car will properly brake. This provides a second emergency circuit. If there is a leak in the first, the piston will move in the cylinder until it comes into contact with the second one. And then it will begin to move, ensuring the proper operation of the brake mechanisms. But if there are leaks in the second circuit, the operation of the mechanism will be slightly different. The first piston will push the second until it rests against the upper part of the metal casing. Then the pressure level in the primary circuit increases and the car starts to brake. And despite the fact that the system works in emergency mode, the car will have time to brake if necessary. If there is a leak in the second circuit, the operation of the master cylinder is different. The first piston pushes out the second, after which it moves to the top of the metal casing. The pressure level in the primary circuit increases. The car starts to brake. Of course, having such malfunctions of the main brake cylinder, to operate the car without repair is simply dangerous. But to reach the nearest garage or service station - it is possible.

Reasons and solutions

What is the main brake cylinder of UAZ? Malfunctions can consist in a drop in the liquid level. Yes, she always comes and goes from there. But this is allowed only when the system is running, that is, when the driver pressed and released the pedal. If, while standing in a parking lot or in a garage, you opened the hood and see the minimum level, it is worth considering why this happened. Basically, this happens because of worn pads - the piston needs more fluid to provide work for compression. Also, the reasons for the failure of the main brake cylinder are in the breakdown of the tubes. They can be made of copper or aluminum. In the bend, they are rubber. If these are metal elements, then they can not be bent - remember this when installing. It happens that the pipe is rubbing the wheel. On some cars, if the highway passes through the arch, it is enveloped by a protective spring. It does not allow the wheel to wipe the material to the ground. At a low liquid level, carefully check the tightness of the entire system, including the service and main brake cylinder. If there is a leak, the tube must be replaced.

Low threshold of sensitivity

There are other signs of malfunction of the master cylinder. For example, the pedal began to work too low, almost in the floor. This happens if the wedged so-called "sorcerer" - the regulator of the distribution of braking forces. The ball may have worn out, or a hole has formed in the hole. Method of elimination - cleaning the insides of the cylinder.

"Soft pedal"

Another sign that indicates a malfunction of the master cylinder is a too soft pedal. This means that the system has accumulated air. It is impossible to operate the car with such a malfunction. There is a risk of overheating the system, since air generates a huge amount of heat during compression. The brake fluid will simply boil. It is very easy to eliminate air strangulation - you need to "pump the brakes". To do this, unscrew the air vent valve in the cylinder and press on the pedal until an ideal liquid flows from it. It does not mean color, but absence of bubbles in it. When the work is completed, the valve closes. In the system it is necessary to add the leaked liquid. But if the problem occurs continuously, it can be a faulty vacuum amplifier valve or a system leakage.

The pedal falls into the floor

This is a significant breakdown. In this case, the malfunctions of the master cylinder are in the non-working pistons, which can not produce the required pressure. As a result, the pads (especially if it's a drum) can not normally contract. The car brakes badly. Also, the banal reason - wear pads. But this can be determined by squeaking. And it's best to keep a record of replacing consumables. This saves considerable time.

Depressurization of the cylinder

If the car brakes poorly and the level of liquid in the reservoir is constantly falling, it is possible that the leak is in the cylinder itself. Carefully inspect the outlets of both circuits and their joints. There should be no leaks in the joints. It is very easy to identify it by the oily stains around the cylinder and by the specific odor. And if in other cases you can "get off" by pumping the system and cleaning channels, then only replacement is needed. Especially if the damage touches the metal case itself. Also, the old element changes to a new one if there are scuffles on the piston. The cost of the new element is about 1-1,5 thousand rubles. In the event that a leak has occurred through the gasket, a master cylinder repair kit is purchased. Change all the technological elements - springs, rubber bands, cuffs.