6.1.1. Maintenance

Constantly you watch serviceability of the working brake system, in due time regulate it and eliminate the arisen malfunctions.

Fig. 260. Main brake cylinder: 1 – protective cap; 2 – a cover with the sensor of emergency falling of level of brake fluid; 3 – tank;
4 – case of the main brake cylinder; 5 – stopper; 6,13 – laying;
7 – stopper insert; 8 – spring; 9 – spring saddle; 10, 19 – washers; 11,
17 – pistons; 12 – the bolt is persistent; 14 – plug limiter; 15 – screw emphasis; 16 – the cuff is sealing; 18 – external cuff; 20 – lock ring; 21 – the plug is connecting


Systematically check liquid level in a tank of the main brake cylinder and in case of need you bring it to norm. Liquid level in a tank 3 (see fig. 260) is checked visually on the tags put on the tank case. At uncovered 2 and new overlays of brake mechanisms the level of liquid has to be on MAX tag. If the hydraulic actuator is serviceable, lowering of the level of liquid in a tank is connected with wear of overlays of blocks of brake mechanisms. Lowering of the level to MIN tag indirectly testifies to their extreme wear. In this case it is necessary to conduct direct control of a condition of slips, and to add liquid in a tank there is no need as at installation of blocks with new slips liquid level in a tank will rise to normal.
The alarm lamp of emergency falling of level of liquid in a tank lights up when the level of liquid falls below MIN tag. At partially worn-out or new overlays of blocks of brake mechanisms loss of tightness of system and leak of liquid is the reason. Add liquid in this case only after restoration of tightness of system.
Along with check of level of liquid in a tank check serviceability of operation of the sensor of emergency falling of level for what press from above the central part of a protective cap 1 (at the included ignition on the dashboard the alarm lamp has to light up).
In the main brake cylinder with two separate tanks liquid level in tanks has to be 15-20 mm lower than the top edges of bulk openings. When replacing worn-out blocks of brake mechanisms do not allow transfusion of brake fluid through edges of tanks of the main brake cylinder.
You watch tightness of connections of pipelines of a hydraulic actuator. Check a condition of pipelines, reliability of fastening of tubes on a frame and bridges of the car. At surveys be convinced of absence of damage of tubes and flexible hoses. Replace tubes and hoses with damages new.

Fig. 262. Pressure regulator drive: 1 – pressure regulator;
2 – arm (basis); 3 – drive lever; 4 – adjusting bolt; 5 – elastic lever; 6, 9, 13 – bolts; 7 – plug; 8 – lever rack; 10 – the plug is expansion; 11 – plug; 12 – rack arm; 14 – lever axis


At seasonal service check operability of the regulator of pressure. Clear the regulator of dirt and check reliability of its fastening. Be convinced by external survey that the regulator and details of its drive are not damaged, brake fluid does not leak and there are no gaps in connection of a rack with the elastic lever and an arm on the back bridge (fig. 262).

Fig. 261. Pressure regulator: 1 – piston; 2 – sealing ring of the piston; 3, 6 – basic washers of a spring of the piston; 4 – piston spring; 5 – case; 7 – piston head sealant; 8 – case plug; 9 – basic washer of the plug of a pusher; 10 – pusher plug; 11 – sealing ring of a pusher;
12 – basic plate; 13 – pusher plug spring; 14 – stopper; 15 – laying of a stopper; 16 – perepuskny valve; 17 – cap; 18 – piston plug;
19 – lock ring; 20 – protective cover


By pressing a brake pedal the piston 1 (see fig. 261) the regulator of pressure has to start from the case on 1,7–2,3 mm. Lack of a piston stroke either the insufficient or excessive course testifies to malfunction of the regulator or its drive.
Pay attention at surveys of a hydraulic actuator to an arrangement of a control cap 17 and lack of dribble from under it brake fluid. In the normal state the cap has to be drowned in a regulator case opening against the stop. Vystupany caps from an opening and dribble of brake fluid mean loss of tightness of sealing rings 11 and, as a result, operability of the regulator.
The vacuum amplifier of adjustments does not demand. Service consists in check of reliability of fastening.
Periodically remove wheels and brake drums, clear details of brake mechanisms of dirt. In summertime and when driving on dirty roads you purge more often.
At removal of wheels and brake drums be convinced of lack of a leak from wheel brake cylinders, and also of reliability of fastening of wheel cylinders to boards. Pay attention to a condition of protective caps of wheel cylinders, degree of wear of frictional slips, and also to a condition of brake drums and disks. At wear of frictional slips to thickness less than 1,5 mm replace blocks new. In case of "oiling" of surfaces of slips smooth out them a grinding skin.
At the removed naves tighten bolts of fastening of brake boards.
For ensuring reliable and safe operation of the brake system regularly (every two years) change brake fluid.

Adjustment
Forward and back mechanisms of the working brake system do not demand adjustment at operation of the car, a necessary gap between blocks and brake disks and
by drums it is supported automatically. When replacing blocks of back brake mechanisms adjust their installation. You carry out operations on replacement and installation of blocks when brake drums completely cooled down and bearings of wheels are correctly adjusted.

Fig. 258. Drive of the main cylinder: 1 – tank;
2 – main brake cylinder; 3 – nut; 4 – vacuum amplifier; 5 – pedal arm; 6 – ottyazhny spring; 7 – fork; 8 – pedal; 9 – finger; 10 – pedal axis; 11 – braking signal switch


Carry out adjustment of a free wheeling of a pedal change of provision of an emphasis (see fig. 258) the braking signal switch 11.
Check a free wheeling of a pedal at the idle engine.
The free wheeling of a pedal measured on movement of the platform makes 5–14 mm.

Filling of a hydraulic actuator of the brake system with liquid and check of operability of system
Hydraulic actuator fill in only with special liquid as directed tab. 1 in the following order:
1. Check tightness of all connections of a hydraulic actuator and a condition of flexible hoses.
2. Lift a cowl and turn off a cover of a tank of the main cylinder. Fill a tank with brake fluid.

Fig. 263. Pumping of the brake system


3. Remove a rubber cap from the perepuskny valve of the brake cylinder of the right back brake mechanism and put on a rubber hose 400 mm long the valve. Lower other end of a hose in the glass vessel with a capacity not less than 0,5 l filled with brake fluid (fig. 263).
4. Unscrew on 1/2–3/4 turns perepuskny the valve then several times press a pedal. Press a pedal quickly, release slowly.
Liquid under pressure of the piston of the main brake cylinder will fill a hydraulic actuator and to force out air. You carry out pumping until allocation of vials of air from the hose lowered in a vessel with brake fluid stops. During pumping add brake fluid in a tank of the main brake cylinder, without allowing an exposure of its bottom that air did not get to system again.
During all operation on filling you hold the end of a hose shipped in liquid.
Carry out pumping of a hydraulic actuator not only when filling with its liquid, but also in case of depressurization of a hydraulic actuator.
5. Densely wrap at the pressed pedal perepuskny the valve of the wheel cylinder, remove a hose and put on a cap.
6. Pump over the brake cylinder of the back left brake mechanism, then pressure regulator, the right and left wheel cylinders of forward brake mechanisms.
7. If the main brake cylinder with two tanks is installed on the car, after pumping of a hydraulic actuator it is necessary to switch off the signaling device for what:
– unscrew perepuskny the valve of the right or left working cylinder of back brake mechanisms;
– smoothly press a pedal before switching off of an alarm lamp on the dashboard; if the alarm lamp blinks, then it will mean that pistons of a signaling device passed neutral situation and therefore operation should be repeated at first, but only unscrewing perepuskny the valve of a forward wheel;
– wrap the valve at the pressed pedal.
After pumping of all brake mechanisms add liquid in a tank of the main brake cylinder.
Densely wrap a cover (covers) of a tank and tighten with the effort excluding its breakage.

Note
Do not add the liquid collected in a glass vessel when pumping in the main brake cylinder. If brake fluid in system dirty, merge it and fill system with fresh liquid.

Do not press a pedal at the removed brake drum or the removed blocks of the forward brake mechanism as under pressure in a hydraulic actuator pistons will be squeezed out of wheel cylinders and liquid will flow out outside.
After filling of system with liquid check the car for braking. At the correct adjustment of brake mechanisms and correctly executed pumping of a hydraulic actuator full braking has to happen within 1/2–2/3 courses of a pedal then the leg has to feel a "rigid" pedal.