7.2.1. Check of brake system
Brakes check on dry, pure, enough smooth and horizontal road. Results of check of brakes will be doubtful if the road wet, slippery or is covered by a dirt. Because of this condition of coupling of all tyres неодинаковы. Results of check will be influenced also by the road having biases as tyres will slide with some withdrawal aside.
Check up brakes on various speeds of the car with easy and strong pressing a brake pedal
, avoiding blocking of brakes and sliding of tyres. Blocking of wheels at braking does not give the full information on efficiency of a brake in comparison with braking when wheels can be turned and the brake way turns out less. This results from the fact that at sliding of the blocked wheel the factor of coupling is less, than at it качении
. Braking process is influenced by three cores of the factor:
- On different wheels there will be unequal conditions of coupling of tyres with road that causes unequal brake forces. Pressure of air and protectors of tyres should be identical;
- Brake forces on forward and back axes should be proportional to vertical loadings operating on them;
- Infringement of corners of installation of wheels can become the reason that the car at braking will pull aside.
For check of leak of a brake liquid press a brake pedal
at engine work on frequency of rotation of idling and the lever of switching of a transmission in neutral position. If the pedal gradually fails at constant pressure, means, there is a leak in system. Visually check up presence of leak and level of a brake liquid in a tank of the main brake cylinder. Insignificant falling of level of a brake liquid occurs because of normal deterioration of linings. Abnormally low level speaks about leak in system. In hydraulic system it is possible both internal, and external leak. If level of a brake liquid in norm, check up length of a rod of the vacuum amplifier of brakes. If the inadequate length of a rod is found out, adjust length or replace a rod.
Check up the main brake cylinder in a following order:
- Check up on absence of damages the main brake cylinder or on absence of leak of a brake liquid round the main brake cylinder. Fall of level of a brake liquid can speak only about leak presence. An abnormal condition is also humidifying of a surface of the main brake cylinder;
- Check up connection of draught of a pedal and length of a rod. If they in norm, disassemble the main brake cylinder and check up on a stretching or swelling of epiploons of the cylinder, then on absence of deterioration of rubber details. If there are inflated epiploons, probably, the non-standard or polluted brake liquid is used. If the polluted brake liquid is found out, all components should be disassembled and cleared, and all rubber components to replace. All pipelines should be washed out also.
The improper brake liquid, either mineral oil or water in a liquid, can cause boiling of a brake liquid or damage of rubber components. If the basic epiploons of the piston in the main cylinder have bulked up, it means that rubber components are spoilt. This malfunction can be confirmed by the bulked up epiploons of the piston of the cylinder of a brake drum on wheels. If deterioration of rubber is confirmed, disassemble all details of hydraulic system, wash out their spirit. Before assemblage dry details a stream of compressed air. Replace all rubber details in system, including hoses. At work of the brake mechanism check up absence of a liquid in linings. If the liquid is found out, replace linings. If a condition of epiploons of the piston of the main brake cylinder normal, check up presence of leak or an excessive overheat. If these conditions are not found out, merge a brake liquid, fill the main brake cylinder and repeatedly merge a liquid from system.