Page 1167 - Foton Workshop Manual - Aumark (BJ1099)

BRAKE - MASTER BRAKE CYLINDER & VACUUM BOOSTER 35-19
ONBOARD CHECKING

1. Check the performance of the vacuum booster
(a). Before starting the engine, press the
brake pedal several times and measure
the height of the brake pedal, which shall
remain unchanged.

(b). Press the brake pedal and start the engine.
If feel the the brake pedal is slightly sinking,
it means the vacuum booster is in normal
condition.

2. Check the air-tightness of the vacuum booster
(a). Switch off the engine after running 1-2
minutes. Press the brake pedal several
times (1st, 2nd and 3rd times). If the brake
pedal rises gradually, it means the vacuum
booster is in good air-tightness. 35
(b). When the engine is running, press the
brake pedal and then switch of the
engine. If the height of the pedal remains
unchanged within 30 seconds, it means the
vacuum booster is in good air-tightness. If it
continues to sink, it means the air-tightness
is inferior and needs overhaul.

Page 1167