Brake drive device VAZ-2106 and VAZ-2103 (VAZ-2106)

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The hydraulic drive includes a brake pedal 33, a vacuum booster 18, a master cylinder 19, a reservoir 20, a rear brake pressure regulator 25, wheel cylinders of the brake mechanisms, pipelines and hoses.

The vacuum booster reduces the force applied to the brake pedal during braking. Between the body 72 and the cover 63 of the vacuum booster, the outer belt of the rubber diaphragm 61 is clamped, dividing the booster into a vacuum and atmospheric cavity. The vacuum cavity is connected to the engine intake pipe via a hose with a tip 58 and a valve. To seal the connection, the tip of the hose is connected to the booster via a rubber flange.

Inside the vacuum booster there is a plastic valve body 62, the tail of which is sealed at the outlet from the vacuum booster cover by a seal 67. It is installed in the cover seat and pressed against the flange of the seat by a spacer ring, which is locked by a locking ring. To protect the movable tail of the valve body from contamination, a corrugated protective cover 71 is put on the flanged part of the booster body and on the tail of the valve body.

The valve body contains a buffer 64, a piston 66 with a pusher 70, a rubber valve 68, springs with support cups and an air filter 69. A channel is made in the body 62 through which the atmospheric cavity is connected to the vacuum cavity.

A thrust plate 65 enters the groove of piston 66, the other end of which rests against the belt of diaphragm 61, which prevents it from falling out. Plate 65 fixes the piston in the housing 62 in assembly with pusher 70 and valve 68. Rod 59 of the piston drive of the main cylinder rests against buffer 64. At the exit from the vacuum booster housing, the rod is compressed by seal 73, which is pressed by collar 74 to the socket of the booster housing. Bolt 75 is screwed into the end hole of the rod, which regulates the exit of the rod from the booster housing (1.05-1.25 mm). The ball head of the pusher 70 is compressed in the piston seat.


The rubber valve 68 is assembled on a pusher. The movable head of the valve, reinforced with a metal washer, is pressed by a spring through a support cup to the rear end of the piston (when fully released). For the movable head of the valve in the housing 62 there is a seat. The fixed flange of the valve 68 is pressed by a spring through the support cup to the inner wall of the valve housing tailpiece, creating a reliable seal. To clean the atmospheric air, a foam air filter 69 is installed in the valve housing tailpiece. The valve housing is constantly pressed by the spring 60 towards the cover 63. The housing and the cover of the amplifier are connected to each other by inserting the projections of the cover into the recesses of the housing and then turning the cover until its edges are inserted under the projections of the housing. The joint between the cover and the housing is sealed by the flange of the rubber diaphragm 61, clamped between them.

The master cylinder 19 is secured to the vacuum booster with two studs. Three threaded holes are made in its housing on top for the pipe fittings that drain fluid into the front and rear brake drive circuits, and two sockets in which the fittings 52 are secured with lock washers and connected by hoses to the tank 20. The inner opening of the cylinder is machined with great precision and high surface purity. On one side, the cylinder cavity is closed with a plug 48. Two pistons are installed in series in the cylinder, one of which actuates the rear brakes, the other - the front ones. Between the plug and piston 47, as well as between pistons 47 and 44, return springs 45 are installed, under the action of which they return to their original position when releasing the brakes. In this case, the piston stroke is limited by screws 46, the tails of which enter the longitudinal grooves of the pistons.

Piston 47 of the rear brake actuator is sealed in the cylinder by two rings 51. The front ring is pressed to the end surface of the groove by spring 50. The other end of the spring rests against cup 49. The rear ring is pressed to the end of the piston by spring 45 through washer 55.

Piston 44 of the front brake actuator has a similar seal, only the rear ring is located in the piston groove and has a different shape.

Spacer bushings 56 are loosely mounted on both pistons. In the initial position of the piston, the spacer bushing, resting against the locking screw, moves the sealing ring away from the end of the groove. In this case, the working cavity of the cylinder communicates with the tank 20 through the resulting gap. The groove of the front sealing ring communicates with the working cavity of the cylinder through radial holes and an axial channel in the piston. Therefore, when the fluid pressure in the working cavity increases, the sealing ring is pressed more tightly against the cylinder mirror.

Tank 20 is two-section, made of translucent plastic, which provides visual control over the liquid level. In the lower part of the tank body there are two tips for connecting hoses. Cover 5 is screwed onto the filler neck, which presses the body 4 of the terminal device and reflector 6 to the end of the neck. In the body 1, a device for monitoring the liquid level in the tank is mounted. It consists of float 8, on the rod of which a movable contact 3 is located, and fixed contact 2, fixed in the body 1. When the liquid level decreases, the float goes down and the contacts close the circuit of the control lamp.

Pressure regulator 25 is included in the rear brake drive to prevent pressure increase in this circuit when the load on the rear axle of the wheels decreases. Otherwise, the rear wheels may lock and skid. The regulator is attached with two bolts to the body bracket, and one hole in the bracket is oval, which allows you to adjust the position of the pressure regulator.

The pressure regulator is actuated by a torsion lever 31 (see fig. 22), which is attached to the body by a collar 32 through a rubber support bushing 33. The long arm of the lever 31 is pivotally connected through a rod 12 to the rear axle beam, and the short arm passes through the opening of the axle 29 and enters the cutout of the lower part of the piston 16 (see fig. 26) regulator. This arm transmits the oscillatory movement of the rear axle beam to the piston.

The pressure regulator body has fittings for two pipelines screwed into it: the lower one is for supplying fluid from the master cylinder, and the upper one is for supplying fluid to the wheel cylinders.

The piston 16 of the regulator at the outlet from the housing is sealed by a ring 9, located in a metal cage. This ring is pressed by a spring 10. The upper end of the spring rests against the floating plate 11 and through it against the piston shoulders. The spring tends to press the piston until it rests against the plug 14. The bushing 13 is loosely put on the piston head. It limits the rise of the seal 12 upwards to the piston head.