The heart of the braking system is the master cylinder. It sets in motion the pads of all wheels of the car. But sometimes there are troubles in the form of fluid leaks. Repair is useless; complete replacement of the assembly is much more effective.
The basis of any car is the braking system. On VAZ cars, it is double-circuit. To put it simply, the main brake cylinder contains two pistons. One creates fluid pressure in the pipes going to the front wheels, and the second to the rear. Braking efficiency and safety are ensured with this scheme of work. If a leak is formed in one of the circuits, then braking will be carried out by another circuit. To improve controllability, an amplifier (vacuum) is installed between the pedal and the brake cylinder rod. With its help, the effort applied to the pedal is significantly reduced. But the stable operation of the system also depends on the condition of the master cylinder. Sometimes it leaks, causing the efficiency of the system to dramatically decrease.
Replacing the master cylinder
To carry out the work, you will need a small set of tools:
• special wrench for brake pipes;
• syringe;
• brake fluid;
• new master cylinder;
• keys for 10 and 13 (cap and open-end).
The first thing to start with is pumping fluid out of the system. The work is done with the help of a syringe, with which all the liquid is pumped out of the expansion tank. Try not to pour it on the ground, even if you intend to refuel fresh afterwards. First, you will damage the soil or concrete. Secondly, even a liquid that has worked out its resource will come in handy. For example, for removing rust and for cleaning threaded connections. Thirdly, if it hits the car body, it can simply eat away paint and varnish.
How to change the master brake cylinder for a VAZ on your own and not be mistaken? It's simple, after draining, using a special key, we turn off all four metal pipes from the brake cylinder. It is not recommended to do this with a simple open-end wrench, since there is a high probability of licking the edges. And then only a complete replacement of all pipelines will save. We also disconnect the two hoses coming from the expansion tank. Using a 13 key, unscrew the two nuts with which the cylinder is attached to the body of the vacuum amplifier. That's it, the node is removed, you can take a new one and put it back in place in the reverse order.
Bleeding the brake system
Since the unit was replaced, bleeding of the entire system is required. The essence of the procedure is to get rid of the air in the tubes and cylinders. You will need an assistant to work. The pumping is done in the following sequence:
• rear right wheel;
• rear left;
• front right;
• front left.
As you can see, first, those wheels are pumped that are located at the maximum distance from the cylinder. On each wheel there are special fittings for bleeding, you need to put on a hose of a suitable diameter, the second edge of which is lowered into a jar with a small amount of brake fluid. Having filled the tank with liquid, the partner begins to squeeze the brake pedal all the way. Having pressed the pedal 4-5 times, he fixes it in the extreme position. At this moment, you unscrew the fitting half a turn so that the air leaves the system. Do this until the air stops flowing. When the brake fluid comes out of the hose, tighten the fitting and move on to the next wheel.
