The vehicle for the safety of traffic on the highways Turkey braking sys-tems, the use of tested and approved by the authorities of parts is a legal re-quirement. For this purpose, it is necessary to check whether the system is working properly with various tests. In our country, a periodic inspection of approximately one million heavy vehicles is carried out annually. Generally, heavy vehicles have air braking system. In the air brake system; In order to determine the amount of air leakage in the system, tests such as leak test, load adjustment valve (Alb) test, four-way safety valve test, check valve test, yellow and red coupling break test, which adjust the brake forces ac-cording to the load condition of the heavy vehicle, are performed. In this study, it is aimed to carry out “Leak Testing”, which is one of the air brake system tests of heavy vehicles, with computer support, increase the reliability of the test and minimize the time the operator spends for the test. For this purpose, a tester and test software have been developed. As a result of the study, instead of the current manual test, this test device and software devel-oped increased test reliability and saved 4 minutes of test time.