18.1. Description of a design
Scheme of a hydraulic actuator of brakes: 1 - contour pipeline "the left forward-right back brake"; 2-signaling device; 3 - the contour pipeline "right forward - the left back brake"; 4 - tank of the main cylinder; 5 - main cylinder of a hydraulic actuator of brakes; 6 - vacuum amplifier; 7 - brake pedal; 8 - regulator of pressure of back brakes; 9 - cable of the parking brake; 10 - brake mechanism of a back wheel; 11 - adjusting tip of the parking brake; 12 - lever of the drive of the parking brake; 13 - brake mechanism of a forward wheel.
Description of a design
The working brake system - with the hydraulic, double-circuit drive and with diagonal division of contours, is equipped with pressure regulator, the vacuum amplifier and the signaling device. At refusal of one of contours of the drive of the brake system the second contour provides braking of the car, though with smaller efficiency.
Brake mechanisms of forward wheels — disk, with a one-piston floating bracket. Brake mechanisms of back wheels — drum, with two-piston wheel cylinders and automatic adjustment of gaps between blocks and drums. The device of automatic adjustment of a gap is located in the wheel cylinder.
The main brake cylinder fastens to the case of the vacuum amplifier on two hairpins. The translucent polyethylene tank on which tags of the maximum and minimum levels of liquid are put is inserted into openings in the top part of the cylinder on rubber consolidations. Pistons in the main brake cylinder are located consistently, the neighbor to the vacuum amplifier puts in action left forward and right back brake mechanisms, and distant - right forward and left back.
The vacuum amplifier is located between pedal knot and the main brake cylinder and fastens to an arm of pedal knot on four hairpins. The amplifier - a non-demountable design, at failure it is necessary to replace him. The simplest check of serviceability of the amplifier: on the car with the killed engine several times we press a pedal of a brake and, holding it pressed, we launch the engine. At the serviceable amplifier from the beginning of operation of the engine the pedal has to leave noticeably forward. Failure or insufficient efficiency of the vacuum amplifier can be also caused by leakage of the hose connecting a working cavity of the amplifier and an inlet pipe of the engine, and also backpressure valve of a hose.
The signaling device serves for the warning of the driver of damage (pressure drop) to one of contours of the brake system. The internal cavity of the signaling device is divided by two pistons into two isolated cameras, each of which is a part of one of contours of the brake system. At pressure drop in one of cameras pistons move in its direction, influencing a rod of the switch of the control alarm lamp of critical condition of the brake system which is on the dashboard — the lamp lights up.
The regulator of pressure of back brakes serves for maintenance of an optimum ratio of pressure in drives of forward and back brakes on purpose not to allow the advancing blocking of back wheels in relation to lobbies at various loading of the car. The load spring fixed by one horse on a regulator arm, and to others on a beam of the back bridge influences on press the regulator lever, reducing pressure in the drive of back brakes. Influence of a load spring on press the lever of subjects is stronger, than load of a back axis of the car is higher. The arm of the regulator of pressure of back brakes fastens on three hairpins to the body bottom in a back part on the right.
The floating bracket of a forward brake contains a support and the wheel cylinder which are pulled together among themselves with two screws. Two bolts the cylinder fastens to the fingers established in nests of a guide of blocks. In these nests lubricant is put. Between fingers and a guide of blocks rubber protective covers are established. To grooves of a guide brake shoes are drawn in by springs. The piston with a sealing rubber ring of rectangular section is installed in the cylinder. Due to elasticity of this ring the constant optimum gap between blocks and a brake disk is supported.
Brake disks - pig-iron. Minimum admissible thickness at wear - 10,8 mm, the maximum beating on external radius - 0,15 mm.
Back wheel cylinders are supplied with the device for automatic maintenance of a gap between blocks and a drum. At wear of brake slips persistent rings under the influence of pistons move at a wear size. In case of damage of a mirror of the cylinder under the influence of the mechanical impurity which got to brake fluid or formed under the influence of corrosion (availability of water in brake fluid), rings can "sour" in the cylinder and one or both pistons will lose mobility. Cylinders in this case need to be replaced.
The drive of the parking brake system - mechanical, hummock, on back wheels. It contains the lever, an adjusting tip, a cable, the equalizer of two branches of a cable, levers of the drive of blocks and expansion levels.