As a vehicle inspector or mechanic, it's crucial to ensure that the braking system of a vehicle is functioning properly to ensure the safety of the driver, passengers, and other road users. A thorough inspection of the brake system is essential to identify any potential issues before they become major problems. In this article, we'll provide a comprehensive checklist for brake system testing, covering the key components and procedures to ensure a thorough inspection.
In-Vehicle/Engine Start
Before starting the inspection, ensure the engine is turned off and the parking brake is engaged. Start the engine and allow it to warm up for a few minutes. This will help to circulate the brake fluid and ensure the brake system is functioning properly.
Parking & Trailer Brake Check
Verify the condition and responsiveness of both parking and trailer brakes:
Push in the trailer parking brake.
Put the truck in drive (D).
Accelerate gently to test the truck parking brake.
Check the trailer brakes:
Pull out the trailer brake.
Push in the truck parking brake.
Accelerate gently to test the trailer brakes.
Service Brake Check
Test the service brakes to ensure they are operational and effective:
Push in the trailer brake.
Move forward at 5 mph.
Apply the service brake.
Check that the steering wheel or truck does not pull left or right.
Pull out the truck and trailer brake valves.
Air Brake Check (LAB)
Check the air brake system:
Air pressure is between 120-140 PSI, governor cut off.
Engine off, switch on.
Push in brake valves.
Fully press the brake pedal.
Wait for the pressure to stabilize.
Check that the pressure does not drop more than 4 pounds in 1 minute.
Check for leaks:
If the pressure drops more than 4 pounds in 1 minute, the truck has leaks.
If the pressure stabilizes, the truck has no leaks.
Check the air brake alarm:
In 55 PSI or before, the air brake alarm activates.
Check the emergency brakes:
Between 20-45 PSI, the emergency brakes pop out.
Fan/pump the brake pedal until both emergency valves come out.
If both valves come out, they are working.
By following this comprehensive checklist, you'll be able to ensure that the braking system of a vehicle is functioning properly and identify any potential issues before they become major problems. Remember to always follow proper safety procedures and consult the vehicle's owner's manual for specific guidelines on brake system testing.
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