11. Brake system

General information

The cars described in the present manual are equipped with the hydraulic brake system with vacuum strengthening. On forward wheels disk brake mechanisms (see an illustration below) are always installed whereas mechanisms of back wheels can have as disk (see an illustration below), and a drum design.

Typical scheme of an arrangement of components of the disk brake mechanism of a forward wheel

1 — the Brake hose
2 — the Support

3 — the Brake disk
4 — the Directing support finger

Typical scheme of an arrangement of components of the disk brake mechanism of a back wheel

1 — the Support
2 — support Bolts

3 — the Brake hose
4 — the Brake disk

All brake mechanisms have a self-regulating design. At the same time compensation of wear of brake shoes of disk mechanisms (forward and back) is carried out automatically whereas, special adjusting devices which activation happens during braking, and also at raising of the parking brake are installed on drum brake mechanisms.

The dual design of the main brake cylinder (MBC) equipped with two separate tanks allows to break a hydraulic path into two, acting independently from each other, a contour. The last means that in case of refusal one of contours, the second continues to work as before, providing adequate braking of the car. Hydraulic contours have a diagonal arrangement. The refusal of any of contours, naturally, leads to decrease in efficiency of braking and is followed by operation of a control lamp on an instrument guard when squeezing a pedal of a foot brake.

Main Brake Cylinder (MBC)

GTTs is established on the assembly of the servo-driver of the vacuum amplifier of brakes fixed on a back partition of a motive compartment. From above on the cylinder the big tank of hydraulic liquid equipped with a plastic cover is located. Fastening of the tank is carried out by means of a collar.

As it was already mentioned above, GTTs has the dual design providing functioning of two independent hydraulic contours. Liquid pressure in each of contours is forced by the individual piston in the main cylinder.

Valve regulator

Besides the vacuum amplifier the hydraulic actuator of the brake system switched on the double-circuit regulator of pressure of back brakes. The valve regulator of pressure is installed on a back partition of a motive compartment of the car. On the brakes (ABS) equipped with system of anti-blocking the valve is built in the block of the hydraulic modulator located in the right part of a motive compartment.

The valve regulator is switched on in both contours of the brake system and provides restriction of pressure in a hydraulic actuator of brake mechanisms of back wheels, preventing their premature blocking at sharp braking. The valve works on reaching hydraulic pressure in contours of some certain value.
The regulator is not maintainable and in case of failure is subject to replacement assembled.

Vacuum amplifier of brakes

The amplifier uses the depression created in the inlet pipeline for increase in efficiency of functioning of a hydraulic actuator of the brake system. The servo-driver of the vacuum amplifier is fixed on a back partition of a motive compartment.

Parking brake

The control lever is located the parking brake in interior of the car. The driving cable in turn connected to couple of back cables is attached to the lever only to lobbies. At raising of the lever on the models equipped with drum back brake mechanisms, back cables delay the executive levers attached to assemblies of brake boots in mechanisms of both back wheels. At the same time boots get divorced in the parties, nestling on the working surface of reels. On models with disk brake mechanisms of back wheels executive levers are attached to actuation mechanisms of screw type in cases of supports. Levers influence pistons of supports, forcing blocks to nestle on brake disks.

Precautionary measures

At service of components of the brake system of cars it is necessary to observe some special precautionary measures:

   a) For gas station of the brake system use only hydraulic liquid of the class DOT 3;
   b) Frictional overlays of brake blocks / boots may contain noxious to health asbestos. Try not to inhale brake dust, do not blow off it compressed air. Apply to rubbing of components of brake mechanisms only the special cleaning structures;
   c) You monitor observance of all required admissions and efforts of tightening of fixture. At service of components use only the serviceable tool. At the slightest doubts ask for the help experts. Remember that serviceability of functioning of brakes is the key to traffic safety;
   d) Do not make attempts of an independent detachment of components of a hydraulic actuator of the brake system on the models equipped with ABS at all. Remember that pumping of a hydraulic path on such cars is carried out by means of the special equipment;
   e) At the slightest signs of violation of serviceability of functioning of the brake system operation of the car has to be suspended!