Brake drive

Removal and installation of the main brake cylinder

To remove, disconnect the brake fluid level sensor connector. Remove the master cylinder reservoir cap (pic. 7-17). Remove the brake fluid from the reservoir with a syringe.



Disconnect the hydraulic lines from the brake master cylinder and plug their openings. Loosen the nuts securing the master cylinder to the brake booster.

If necessary, remove the reservoir from the master cylinder and remove the O-rings.

Remove the brake master cylinder. Rinse the parts with alcohol and check their condition.

At installation to establish a tank on the main cylinder. Check for the presence of an O-ring on the master cylinder between the cylinder and the brake booster. Install the master cylinder on the brake booster and tighten the fastening nuts to a torque of 2.0 kgf·m. Connect the brake lines to the master cylinder. Pour brake fluid into reservoir. Bleed the air from the hydraulic brake actuator as follows.


Install the master cylinder reservoir cap and connect the brake fluid level sensor connector.

Checking and adjusting the pressure regulator must be carried out on an equipped vehicle, standing on wheels, with a full fuel tank. In this case, the assistant must take the driver's seat. «live» several times the rear suspension. Disconnect the hoses from the brake mechanisms of the left front and right rear wheels. Unscrew the fittings for bleeding the hydraulic drive of the brakes from the wheel cylinders and screw in the fittings of the hoses of the control pressure gauges instead.

Purge air from both gauges. Pressing the brake pedal, measure the pressure in the wheel cylinders using pressure gauges, the values of which must correspond to those indicated in subsection «Device Features».

Adjust the spring tension of the pressure regulator depending on the measurement results: with increased pressure in the rear wheel brake, loosen the spring, and vice versa (pic. 7-18).



If the measured pressure in the rear wheel brake mechanism is not within the specified limits, replace the pressure regulator.


Disconnect control pressure gauges, bleed air from hydraulic brake system.

Removal of air from a hydraulic drive of brakes

Bleeding the brakes is necessary to remove air from the hydraulic drive. Air can get into the hydraulic drive due to depressurization of the system during the repair or replacement of individual components, as well as when replacing the brake fluid. In case of depressurization of one of the circuits of the hydraulic drive of the brakes, air should be removed only from this circuit. The presence of air in the brake actuator is indicated by an increased pedal travel and its «softness». It is recommended to use a special installation for pumping hydraulic actuators under pressure. If not, you can bleed the brake system by depressing the brake pedal. In this case, an assistant is needed. The efficiency of this method is lower, and labor costs are greater than when using a special installation.

When bleeding the rear wheel brakes, move the pressure regulator lever vigorously towards the spring. Bleeding the hydraulic drive of the brakes using a special installation is carried out in accordance with the instructions of the manufacturer of the installation used.

Fill the system with brake fluid at a pressure of 2.5 kgf/cm² through the fitting screwed onto the reservoir of the brake master cylinder.

Remove air first from one circuit, then from another, starting each time with the wheel farthest from the master cylinder, observing the following sequence: brake cylinders of the right rear, left front, left rear and right front wheels.


During pumping, check and, if necessary, top up the fluid in the tank to the norm. Do not reuse brake fluid drained from the system. After removing air from the system, put protective caps on the air outlet fittings. After pumping, press the brake pedal several times to set the pistons to the working position and add brake fluid to the reservoir to the normal level. Check the operation of the service brakes on a test drive.

When removing air from the hydraulic drive of the brakes without special installation, monitor the presence of fluid in the tank, preventing its bottom from being exposed. Before proceeding with pumping, eliminate the influence of the vacuum booster by pressing the brake pedal several times.

Remove air from one circuit first. then from the other, starting each time with the wheel farthest from the master cylinder, observing the following sequence: brake cylinders of the right rear, left front, left rear and right front wheels.

Add brake fluid to the reservoir to the correct level. Remove the protective caps from the air outlet fittings. Clean the fitting from dust and dirt. Put a transparent tube on the head of the brake fitting of the right rear wheel, and lower its free end into a vessel filled with ⅓ clean brake fluid. Press the brake pedal. to pressurize the hydraulic brake system. If no resistance is felt when pressing the pedal, press it slowly and without interruption until then. until pressing does not require any effort. Loosen the fitting ½ turn with the pedal depressed to the full. After that, the assistant should slowly press the brake pedal and slowly release it, while the liquid, together with air, will be forced out of the system through the hose into the vessel. Repeat this process until no more bubbles come out and clear fluid comes out of the hose, keep the pedal depressed and tighten the air outlet fitting tightly. Remove the hose and put on the fitting a protective cap.

Repeat operations for other wheels.

After pumping, restore the level of brake fluid in the reservoir if necessary. Do not use the fluid drained from the system to fill the reservoir, as it is saturated with air, contains a lot of moisture and may be contaminated.