Air brake checks and adjustment basics

Updated October 2026

Out-of-adjustment brakes are among the most common inspection violations and can put a truck out of service.

Daily

Do your air brake checks during the pre-trip: air pressure build-up, governor cut-out and cut-in, leakage, low air warning and spring brake tests.

Adjustment

Automatic slack adjusters reduce adjustment issues, but they still need inspection. If brakes keep going out of adjustment, have a mechanic find out why.

Brush up on air brakes with the free practice test at CDL Permits.