Pre-Trip Inspection – Brake Check

Parking Brake Check

Apply parking brake only and shift into a lower gear. Gently pull against the brake by releasing the clutch, and it should hold the vehicle.

Hydraulic Brake Check

With the engine running, apply the foot brake and hold for five seconds. The pedal should not move (lose pressure) during those five seconds.
If equipped with a hydraulic brake reserve system, with the key in the off position, depress the brake pedal and listen for the sound of the reserve system electric motor turning on.
Check that the warning buzzer and light is off.
Check the proper operation of the foot brake by moving the vehicle forward slowly at about 5 mph and applying the brake firmly.

Air Brake System Check

For air brake equipped vehicles, the proper procedures for inspecting the air brake system are as follows:

Test Air Leakage Rate (Static check)

With a fully-charged air system, typically at 120 psi, turn the engine off, chock the wheels, release (push in) the parking brake button and trailer air supply button (for combination vehicles) and time the air pressure drop. After the initial drop, the rate of pressure loss should not be more than 2 psi per minute for single vehicles and no more than 3 psi per minute for combination vehicles

Test Air Brake System for Leaks

Release (push in) the parking brake and trailer air supply button (for combination vehicles), and apply pressure to the foot brake. After the initial drop in pressure, the rate of pressure loss should be no more than 3 psi per minute for single vehicles and no more than 4 psi per minute for combination vehicles.

Test Low Pressure Warning Alarm and/or Signal

Turn the key to the on position. Rapidly depress and release the foot brake to reduce air tank pressure. The low air pressure warning signal must come on before the pressure drops below 60 psi.

Check that the Spring Brakes Activate Automatically

Continue to rapidly apply and release the service brake pedal further reducing air pressure. The trailer air supply button (for combination vehicles) and parking brake button should pop out when the pressure falls to usually between 20 to 40 psi. This should activate the spring brakes.

Check Rate of Air Pressure Buildup

While the engine is operating at 1800 RPM, the pressure should rise from 85 to 100 psi within 45 seconds in dual air systems.

Test Foot (Service) Brakes

With normal air pressure, release the parking brake and trailer air supply button (for combination vehicles), move the vehicle forward slowly at about 5 mph and apply the brakes firmly using the brake pedal. Test for any pulling to any one side or delayed stopping action.