3.15.2. Check of the brake system

1. Unsatisfactory operation of the vacuum amplifier can be the cause of loss of efficiency of braking. For its express check press several times a brake pedal at the idle engine to remove depression in the amplifier, and then, holding a pedal, launch the engine. If after launch of the engine the pedal fell a little, the vacuum amplifier is serviceable.	2. If the pedal remained motionless, check an integrity and reliability of connection of a hose of the vacuum amplifier with the union on an inlet pipe of the engine …

3. … and with the amplifier. Replace a faulty hose or repair. If the hose is serviceable, it is necessary to replace the vacuum amplifier (see. "Replacement of the vacuum amplifier").

NOTE The hose of the vacuum amplifier is made for a single whole with the backpressure valve. Check its working capacity (see. "Check of operation of the vacuum amplifier of brakes"). In case of malfunction of the backpressure valve replace a hose of the vacuum amplifier assembled.

If braking is followed by a beating and a pulsation of a brake pedal, it is necessary to check first of all a condition of forward disk brake mechanisms.

4. Having installed the car on a jack, serially remove forward wheels and examine brake disks. Thickness of a brake disk has to be not less than 19,0 mm, a disk surface — equal and smooth on both sides. If the disk surface in places is covered with a rust that usually happens after the long parking of the car to not dried brakes, try to smooth out a working surface a small emery cloth. If this procedure did not help, it is necessary to give disks to grinding or to replace new.

5. Check mobility of the piston of the brake mechanism. For this purpose try to get moving forward the piston the screw-driver. If the piston does not manage to be shifted, so jammed it in the brake cylinder.

PREVENTION Jamming of the piston of the brake cylinder leads to constant snubbing of the corresponding wheel at the released pedal and a drift of the car when braking.

If braking is followed by breakthroughs of the car and a scratch around back wheels, and at intensive braking there is a drift of a back part of the car, check a condition of drum brake mechanisms of back wheels.

6. Having installed the car on a jack, serially remove back wheels, remove brake drums (see. "Removal and installation of the brake drum") also measure diameters of their working surfaces. Internal diameter of a drum has to be no more than 201,0 mm, the working surface of the reel — equal and smooth, without ring risok and obviously visible ovality (ovality has to be no more than 0,5 mm, it can be determined by unevenly worn-out working surface of the reel). If the internal diameter of a drum is more admissible, ring risks very deep or uneven wear of a working surface is well visible, the drum should be replaced new.

NOTE The parking brake puts in action back brakes the cables connecting the lever of the parking brake and mechanisms of management of brake shoes. Many drivers try to use as seldom as possible the parking brake to prolong his "life", and achieve opposite result. If you do not use the parking brake, in covers of cables dirt and moisture stands, cables acquire a rust, cease to move and break. Therefore use the parking brake in all cases, when necessary, but do not forget to adjust its drive from time to time (see. "Adjustment of the drive of the parking brake").