6.2.1. Check and adjustment of elements of the brake system
Check brakes on dry, pure, quite smooth and horizontal road. Results of check of brakes will be doubtful if the road wet, slippery or is covered with dirt. Because of this condition of coupling of all tires are not identical. Results of check will also be influenced by the road having biases as tires will slide with some withdrawal aside.
Check brakes at various speeds of the car with easy and strong pressing a brake pedal, avoiding blocking of brakes and sliding of tires. Blocking of wheels when braking does not give 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 when sliding of the blocked wheel the coefficient of coupling is less, than at its swing.
Process of braking is influenced three by the main a factor:
– on different wheels there will be unequal conditions of coupling of tires with the road that causes unequal brake forces. Pressure of air and protectors of tires have to be identical;
– brake forces on forward and back axes have to be proportional to the vertical loadings operating on them;
– violation of angles of installation of wheels can become the reason that the car when braking will pull aside.
For check of leak of brake fluid press a brake pedal during the operation of the engine at a frequency of rotation of idling and the lever of switching of the transmission in neutral situation. If the pedal gradually fails with a constant pressure, so there is a leak in system. Visually check existence of leak and level of brake fluid in a tank of the main brake cylinder. Insignificant falling of level of brake fluid happens because of normal wear of blocks. Abnormally low level speaks about leak in system. In hydraulic system both internal, and external leak is possible. If the level of brake fluid is normal, check length of a rod of the vacuum amplifier of brakes. If the inadequate length of a rod is found, adjust length or replace a rod.
Check the main brake cylinder in the following order:
– check for absence of damage the main brake cylinder or for lack of leak of brake fluid around the main brake cylinder. Lowering of the level of brake fluid can speak only about leak existence. An abnormal condition is also moistening of a surface of the main brake cylinder;
– check connection of draft of a pedal and length of a rod. If they are normal, disassemble the main brake cylinder and check for stretching or swelling of epiploons of the cylinder, then for lack of wear of rubber details If there are inflated epiploons, perhaps, the non-standard or polluted brake fluid is used. If the polluted brake fluid is found, all components should be sorted and cleared, and to replace all rubber components. All pipelines should be washed out also.
Improper brake fluid, or mineral oil or water in liquid, can cause boiling of brake fluid or damage of rubber components. If the main epiploons of the piston in the main cylinder bulked up, it means that rubber components are spoiled. This malfunction can be confirmed with the bulked-up epiploons of the piston of the cylinder of the brake drum on wheels. If wear of rubber is confirmed, sort all details of hydraulic system, wash out them alcohol. Before assembly dry details a stream of compressed air. Replace all rubber details in system, including hoses. During the operation of the brake mechanism check lack of liquid in laying. If liquid is found, replace laying. If a condition of epiploons of the piston of the main brake cylinder normal, check existence of leak or an excessive overheat. If these conditions are not found, merge brake fluid, fill the main brake cylinder and repeatedly merge liquid from system.