Air Brake System: a) audible air leaks (defect 1.1)/ b) air loss rate exceeds limit
(defect 1.4M)
Audible Air leak
You must know that it’s necessary to check for leaks regularly, and a vehicle has the above Minor Defect
WHEN ANY AIR LEAK CAN BE HEARD.
Must say: “I would notify the operator of the defect.”
“Enter the defect on the Daily Inspection Report.”
“Be allowed to drive the vehicle; and get it fixed as soon as possible.”
Air loss rate exceeds prescribed limit
You must know the proper method for testing the air-loss rate, and that a vehicle has the above Major Defect
WHEN THE AIR PRESSURE DROPS IN ONE MINUTE MORE THAN THE PRESCRIBED LIMIT OF:
• 28 kPa (4psi) is one minute for Class A
• 21 kPa (3psi) is one minute for Class D
Must say: “I would notify the operator of the defect.”
“Enter the defect on the Daily Inspection Report.”
“I would put the vehicle out of service and not drive it.”
PROCEDURE:
• TELL THE EXAMINER, “For any air leaks heard at any time, I would conduct the air-loss rate test.”
• Ensure the vehicle is secured by wheel chocks.
• Release all spring parking/ emergency brakes.
• Ensure the air-system pressure is over 90 PSI. Shut off the engine and turn the key on (if required).
• Hold the brake pedal in the fully applied position and start the timer.
• Observe the air pressure gauges for one minute and note any change. (Disregard the initial pressure drop
and begin test after the pressure has stabilized) and TELL THE EXAMINER.