Daewoo Nexia

Since 1994 of release

Repair and car operation

17.3. Check of a technical condition of brake system

THE GENERAL DATA

Brake system check on dry, pure and enough equal platform with a good covering. Reliable check of a condition of brake system on damp or covered with a dirt (including dry sand) a platform will be complicated because of various coupling of tyres with a covering. The rough covering also is not suitable for check of brake system because of strong vertical fluctuations of wheels. The brake system should be checked at various intensity of braking and various speeds of the car. In all cases it is necessary to avoid blocking and sliding of wheels. Blocking of wheels does not speak about effective braking as the brake way thus turns out more in comparison with braking on a coupling limit when the braked wheels continue to rotate. This results from the fact that wheel blocking is accompanied by falling of coupling of the tyre with a road surfacing. The brake system of the car is designed so that to lower probability of blocking of wheels in most cases, most often meeting in usual operation, behind an exception perhaps enough rare emergency braking with extremely big delay. Braking of the car without blocking of wheels not only reduces a brake way, but also provides preservation of stability and controllability of the car.

At the big delays the brake pedal becomes more "rigid".

The external factors influencing for work of brake system:

1) Tyres. The tyres having various contact and coupling with road, will brake differently. It is necessary to support identical pressure of air in tyres. The tyres located on one axis, should have about identical depth of drawing of a protector.

2) car Loading. At non-uniform loading of the car those wheels on which the big share of loading is necessary, demand and большего the brake moment, than the others. Higher efforts are necessary for braking completely the loaded car to a brake pedal.

3) Corners of installation of wheels. Infringement of correct corners of installation of wheels, has especially distributed also a longitudinal inclination of an axis of turn, leads at braking to car withdrawal aside.

The brake system is equipped by a signalling device of malfunction BRAKE which is located on a control panel. At ignition key turn in position START signalling device BRAKE should light up. After return of a key to position RUN the signalling device is switched off. Signalling device BRAKE joins in following cases:

– At inclusion of a lay brake (ignition is included);
– At falling of level of a brake liquid in a tank of the main brake cylinder.

At the idling engine and a neutral in a transmission to press and keep a brake pedal with constant effort. If the brake pedal slowly falls, the possible reason of it are leaks of a brake liquid. It is necessary to examine all brake system on presence of thinnesses. To check up level of a brake liquid in a tank. Small decrease in level of a liquid can be caused normal deterioration brake колодок. Strong falling of level can testify to presence of leaks of a liquid. In a brake hydrodrive are possible both internal, and external leaks of a liquid. If level of a brake liquid normal, it is necessary to check up length of a pusher of the vacuum amplifier. If the length of a pusher differs from norm, it is necessary to adjust or replace a pusher. To check up adjustment of working brake system and a lay brake.

Mentioned below checks of the main brake cylinder do not guarantee detection of all possible malfunctions of knot.

1) to Check up presence of cracks of the case of the cylinder and traces of a brake liquid on an external surface of the cylinder. Falling of drops of a brake liquid testifies to leaks. Cylinder humidifying outside is admissible.

2) to Check up presence of jammings in a drive of a pedal and length of a pusher. If malfunctions it is not revealed, to dismantle and disassemble the cylinder. To check up a condition of consolidations of the cylinder and pistons. If consolidations have inflated or were extended, the possible reason of it is the brake liquid improper or polluted by extraneous substances. In this case необходи мо completely to disassemble the cylinder and to wash out all details. Rubber details are subject to obligatory replacement. It is necessary to wash out all hydrodrive of brake system also.

Application of unrecommended marks of brake liquids, and also hit in a hydrodrive of mineral oil or water leads to decrease in temperature of boiling of a working liquid and failure of rubber consolidations.

Swelling of external sealing covers on the main thing or wheel brake cylinders testifies to failure of internal rubber consolidations.

At detection of signs of swelling of rubber details it is necessary to disassemble and completely to wash out all hydrodrive spirit. Before assemblage it is necessary to dry up a stream of compressed air all details of a hydrodrive for a hit exception in brake system of spirit. Rubber details, including brake hoses, are subject to replacement. It is necessary to check up also presence of traces of a brake liquid on brake overlays. At strong pollution of overlays it is necessary to replace them. If consolidations of the main brake cylinder in an order, the possible reason is the overheat of a brake liquid. In the absence of an overheat it is necessary to merge a brake liquid, to wash out system a fresh brake liquid, to fill in a new brake liquid and to remove air from a hydrodrive.