2.14. Check of the brake system
In addition to the established intervals of servicing of brakes it is necessary to check them at each removal of a wheel in the presence of suspicions for emergence of damages.
The main signs of malfunctions is the following:
– withdrawal of the car in one party at intensive braking;
– the increased brake way;
– strong squeal when braking;
– leak of brake fluid, usually on an internal part of the tire or a wheel.
Weaken bolts of fastening of a wheel.
Lift the car a jack or the elevator.
Turn out bolts and remove a wheel.
As practice shows, front brake shoes from the passenger wear out more intensively therefore and it is necessary to check brake shoes on the right forward wheel.
Weaken bolts of fastening of the right forward wheel and turn on the parking brake, then lift a forward part of the car and fix on supports. Remove the right forward wheel.
On disk brakes in each support about two blocks are established. Internal brake shoes are visible through observation ports in each support. External brake shoes are visible sideways a support. Visually determine thickness of brake shoes.
If it is visually difficult to determine thickness of brake shoes or there is a suspicion on an unsatisfactory condition of blocks, remove them for further survey. If the overlay of a brake shoe is worn-out to thickness of 1 mm, it is necessary to replace all four brake shoes in a set.
Measure by a micrometer thickness of a brake disk. If it is less maximum permissible, replace a disk. Check a condition of a brake disk for lack of cracks and zadir.
Before installation of a wheel check a condition of brake hoses and tubes.
Check a condition of a rotor of the ABS sensor. At detection of damages it is necessary to remove for service knot a nave/rotor.
Establish a wheel and lower the car.
Back drum brakes
Install the car on the firm horizontal platform.
Enclose an emphasis under forward wheels.
Weaken bolts of fastening of back wheels, lift a back part of the car and fix on supports. Remove back wheels.
Remove brake drums / naves of back wheels.
During the work of brake shoes brake dust which contains asbestos, unhealthy therefore when cleaning brake shoes do not use compressed air is formed and do not inhale dust.
For cleaning of brake mechanisms use only a special cleaner of brakes.
Measure by a caliper thickness of overlays of back brake shoes. If overlays of brake shoes are higher than heads of rivets on 1,0 mm, brake shoes are suitable for further operation, otherwise replace all four brake shoes in a set. Brake shoes need to be replaced if overlays of blocks with cracks, "are licked" or polluted by brake fluid.
Check a condition of the returnable and holding springs of back brakes.
Turn off protective covers of working brake cylinders and check for lack of leak of brake fluid. If under protective covers brake fluid is found, replace working brake cylinders.
Check a condition of brake drums for lack of cracks, scratches, deep flutes and podgoraniye. If defects cannot be eliminated, replace brake drums.
Install brake drums.
Establish wheels and lower the car.
Slowly tighten the parking brake with effort of 10 kg, the lever has to rise by 6–8 clicks. Otherwise adjust the parking brake.
Install the car on the road with a bias, lift the lever of the parking brake, move the gear shifting lever to neutral situation. If the car reliably is kept by the parking brake, so it normally works and is correctly adjusted.
Vacuum amplifier of brakes
The vacuum amplifier of brakes reduces the effort enclosed to a brake pedal, facilitating thereby driving. The principle of operation of the vacuum amplifier of brakes is based on use of depression in an inlet collector. At failure of the vacuum amplifier operability of the brake system is not broken, but for pressing of a pedal of a brake it is necessary to make considerably bigger effort.
Press several times a brake pedal at the idle engine to create the identical pressure close to atmospheric in cavities of the vacuum amplifier. At the same time determine by the effort enclosed to a pedal whether there is no jamming of the case of the valve. Stop a brake pedal in the middle of its course and launch the engine. At the serviceable vacuum amplifier the brake pedal after launch of the engine has to move forward. If the pedal does not move, check fastening of a tip of a hose, connection of fastening of a flange of a tip in the amplifier, a condition of a hose and the union.