Method for testing vehicle power braking system

To test a vehicle power braking system, a piston of a power brake pressure generator is displaced twice for a pressure build-up and in between back preferably by a longer distance. Extension of the piston travel during the second displacement is an indication of air in a cylinder of the power brake pressure generator due to an excessively low brake fluid level in a brake fluid reservoir. 为了检查助力车辆制动设备，本发明提出，两次在压力形成的意义上移动助力制动压力产生器（1）的活塞（3）并且在此之间使其返回移动优选更长的行程。如果在第二次移动时的活塞行程延长，那么由于制动液储存容器（16）中太低的制动液水平而可以推断出在所述助力制动压力产生器（1）的缸（3）中存在空气。