DOT Brake Inspection: A Preventative Checklist

A DOT Level 1 Inspection is the most comprehensive inspection you can undergo.The inspector will physically get under your truck and trailer.According to the CVSA, brake - related violations account for the highest percentage of Out - of - Service(OOS) orders during roadside inspections.

An OOS order means you cannot move your truck, your load is late, and your carrier's safety rating takes a massive hit. Here is how to pass.

The 4 - Step Brake Checklist

1. Air Leakage Test(The "Applied" Leakage Test)

This is the first thing the DOT officer will ask you to do in the cab.

• Build air pressure to maximum(until the governor cuts out, around 120 - 130 psi).
• Turn the engine OFF.Turn the key to the ON position.
• Release both parking brakes(push the red and yellow valves in).
• Apply firm pressure to the foot brake and hold it for one full minute.
• The Rule: You cannot lose more than 4 psi in one minute for a combination vehicle(truck and trailer).

2. Low Air Warning Alarm Test

- While the engine is still off, rapidly pump the foot brake to fan down the air pressure.

• The Rule: The low air warning light and buzzer MUST activate before the pressure drops below 60 psi.

3. Brake Adjustment(Pushrod Travel)

This is what gets most drivers put Out - Of - Service.Automatic Slack Adjusters(ASAs) are standard now, but they can still fail or be improperly maintained.

• The inspector will measure the pushrod travel when the brakes are applied.
• For a standard Type 30 brake chamber, the legal limit for pushrod travel is 2 inches.If it travels more than 2 inches, the brake is considered out of adjustment.
• If 20 % or more of your brakes are defective or out of adjustment, you are Out - Of - Service immediately. (For an 18 - wheeler with 10 brakes, if just 2 brakes are bad, you are shut down).

4. Visual Inspection of Components

Get under your truck during your pre - trip.Look for:

- Cracked or chafing air hoses.If you can see the colored reinforcement braiding showing through the black rubber tube, it is an OOS violation.

• Missing cotter pins on clevis pins.
• Cracked brake drums.
• Oil or grease leaking from the wheel seal onto the brake linings.

Pro Tip: If an inspector pulls you into the scale house, be polite, be professional, and have a clean dashboard.A clean, organized cab often indicates to the officer that you also maintain your equipment well.