6.1.2. Check of operation of the vacuum amplifier of brakes without a tester

Fig. 6.3. Check of operation of the vacuum amplifier

Start the engine for one-two minutes and then muffle it. Several times press not a brake pedal with usual effort when braking. If by the first pressing a brake pedal it is squeezed out against the stop, and by the subsequent pressing its course gradually decreases, the vacuum amplifier works normally. If by consecutive pressing a pedal its course remains invariable, the vacuum amplifier of brakes means (fig. 6.3) is faulty.

At the idle engine press several times a pedal of a brake and be convinced that the course of a pedal of a brake changes. Then, without releasing a brake pedal, start the engine. If the brake pedal slightly fell, it means that the vacuum amplifier is serviceable. If after engine start the pedal remained on a place, the vacuum amplifier means is faulty.

Fig. 6.4. Check of serviceability of the vacuum amplifier

At the working engine press a pedal of a brake and then muffle the engine. Hold a pedal of a brake pressed during 30 pages. If the provision of a pedal does not change, the vacuum amplifier of brakes means is serviceable. If the pedal of a brake rises, the vacuum amplifier means (fig. 6.4) is faulty.

If results of one of the carried-out checks appeared unsatisfactory, it is necessary to look for malfunction in a vacuum hose, the return valve or the vacuum amplifier of brakes.