CDL Class A Brake Bleed Down Flashcards

Pre-Check Procedures

• Ensure parking brakes are engaged and vehicle placed in 1st gear.
• Keep the vehicle key in your pocket to avoid ignition.
• Use three points of contact when exiting and entering the cab.
• Remove and apply chock blocks to wheels as necessary.
• Always wear a seatbelt while in the cab.

Step 1: Governor Check

• Start engine in neutral and rev to 1200-1400 RPM.
• Build air pressure to 120-125 PSI, ensuring system is fully charged.
• Release parking brakes, observing pressure drop to 100 PSI for governor activation.
• Repeat the revving to confirm governor cut-out.
• Turn off engine, leaving key in ON position for gauge power.

Step 2: 3PSI Air Loss Rate Check

• Release parking brakes and monitor air loss.
• After an initial drop of 5-15 PSI, ensure loss does not exceed 3 PSI in one minute.

Step 3: 4PSI Air Loss Rate Check

• While holding service brake, check air loss.
• After an initial drop of 5-15 PSI, ensure loss does not exceed 4 PSI in one minute.

Step 4: Low Air Pressure Warning Check

• Continuously pump the service brake until low air pressure warning activates between 60-70 PSI.

Step 5: Spring Brake Check

• Pump the service brake until red and yellow valves engage at 20-45 PSI.

Step 6: Compressor Recovery Check

• Start engine in neutral and rev to 1200-1400 RPM.
• Check if air pressure rises from 85-100 PSI within 45 seconds.
• Continue until the system is fully charged and ensure parking brakes are set before leaving the cab.

Step 7: Trailer Parking Brake Check

• With the engine on, release tractor parking brake and attempt to move the vehicle.
• Tug against the trailer parking brake to ensure it holds.

Step 8: Tractor Parking Brake Check

• Release trailer parking brake and test vehicle movement.
• Tug against tractor parking brake to ensure it is functional.

Step 9: Trailer Service Brake Check

• Move the vehicle forward at 5 mph; engage trolley brake to test stopping ability.
• Fully release the trolley brake after the check.

Step 10: Tractor Service Brake Check

• Again moving forward at 5 mph, depress the service brake and ensure the vehicle stops without lateral movement.

After Finishing Brake Bleed Down

• Engage parking brake, shift to lowest gear, and turn off the engine.
• Take the key and exit the cab using three points of contact.
• Always close the door after exiting.

Test your knowledge on the essential steps for the Brake Bleed Down procedure in Class A CDL. This quiz covers key steps to ensure safety and compliance before operating a vehicle. Perfect for CDL students preparing for their examinations.