The Commercial Vehicle Safety Alliance (CVSA) is at it again. Next week — Aug. 24-30 — is Brake Safety Week in North America. That means truck inspectors will be out in force, peeking under hoods, poking around your spiders and cams, and probing your drums and rotors.
Is your fleet ready for the “rubber glove” treatment?
CVSA inspectors will conduct routine Level 1 vehicle inspections, focusing on brake systems and components. Special emphasis this year is on brake drums and rotors. According to CVSA, brake drum and rotor issues can affect a truck’s brake efficiency and safety.
“Broken pieces of drums and rotors may become dislodged from the vehicle enroute and damage other vehicles or result in injuries or fatalities to the motoring public,” CVSA noted in a news release.
In April, CVSA conducted an unannounced one-day brake safety inspection and enforcement event focusing on brake drums and rotors. Out of 4,569 logged inspections, 4,171 trucks (91.3%) were found to be free of drum and rotor defects.
Of the 398 trucks sidelined that day (8% of the total), 237 exceeded the 20% brakes OOS (out of service) criterion. A total of 289 brake defects were uncovered, including those that exceeded the 20% margin.
That’s respectable performance, considering the historic OOS rate for brake defects usually runs closer to 12-14%.
Drum and rotor OOS criteria
According to the latest 2025 handbook, the following drum or rotor (disc) conditions are considered standalone OOS violations, meaning the vehicle must be pulled from service immediately:
Drum cracks: Any portion of the brake drum has an external crack or a crack that opens upon brake application.
Missing/dangerously damaged drum or rotor: Any portion of the drum or rotor is missing or appears to be in danger of falling away (ie., large chunks broken off, compromised integrity).
Rotor cracks: Any rotor (disc) that exhibits a crack that spans more than 75% of the friction surface and penetrates completely through the rotor — from either side to the center vent (for vented rotors), through a solid rotor, or through any structural support connecting the friction surfaces.
Rotor worn through vents: The rotor’s friction surface is worn to or through its center vents.
Metal-to-metal contact: Rotor or drum has evidence of metal-to-metal contact on the friction surface.
Rusted rotor: Rotor has severe rusting across the entire friction surface on either side of the rotor.
Contamination: Friction surface contaminated by oil or grease.
Not just about drums and rotors
Any truck pulled in for a brake inspection will get a full going over. Don’t kid yourself — this isn’t about only drums and rotors. A heads-up from Bendix Commercial Vehicle Systems warns brake inspections will run the gamut.
They’ll be checking for:
- Air leaks around brake components and lines;
- Air pressure in the target range of 90-100 psi when checking for air leaks;
- Broken springs in the spring brake housing section of the parking brake;
- Holes in tubing caused by rubbing;
- Mismatched air brake chamber sizes across axles;
- Missing, nonfunctioning, loose, or cracked parts;
- Proper operation of the tractor protection system;
- Proper brake chamber pushrod travel;
- Drum brake S-cam has “cammed over”;
- Slack adjusters on the same axle are not at the same length;
- Warning device functionality.
“What goes on in the wheel-ends and braking system directly impacts multiple aspects of safe vehicle operation,” said Brian Screeton, manager – technical training and service at Bendix. “There’s no overstating the importance of keeping up with maintenance and inspection of those areas.”
There’s lots of redundancy engineered into today’s air brake systems, which can be a blessing and a curse. There’s plenty of stopping power in reserve beyond what you’d call a normal brake application. In many normal braking instances, you might never notice a decrease in performance if a defect was present.
It’s when you get to hard brake applications or situations and release timing as well as balance is critical, that your brakes need to be 100% functional. This issue came up in our recent stories about preventing jackknife and roll-over crashes.
If a CVSA inspector uncovers a brake defect and a roadside inspection, they aren’t just giving you a ticket, they could be doing you a big favor.
“Any indication of something out of compliance can be a sign of potentially wider maintenance issues,” Screeton said. “Taken individually, everything inspectors are looking for – such as kinks in an air hose or an active full-stability light on the dash – may seem inconsequential. One small sign of something out of compliance can be an indicator of more widespread maintenance issues.”
Preparing for Brake Safety Week
With CVSA turning up the heat during Brake Safety Week, now is a perfect time to have a really good look around your brake system, especially the wheel-ends. But really, this is an exercise that demands daily, or at the very least weekly, attention.
“Inspections — pre-, post-trip, and regular — can make a difference toward catching brake-related issues before they become problems, everything from damaged components like air brake chambers or pushrods to loose, chaffed or kinked hoses,” Screeton said.
Here are Screeton’s suggestions for minimum driver brake inspections:
Daily checks:
- Check for damaged or loose-hanging air brake chambers, pushrods, or slack adjusters;
- Make sure slack adjusters on each axle are extended out to the same angle. Different angles can indicate an out-of-adjustment brake, a broken parking brake power spring, or a broken service brake return spring;
- Examine tubing and hose condition, positioning, and connections;
- Check for moisture in the air system to prevent contamination that leads to component deterioration and system leaks.
Weekly checks:
- Perform a 90-to-100 psi brake application with the wheels chocked, the engine off, and the parking brakes released. Listen for leaks and observe pressure gauges for air loss;
- Check disc brake rotors for cracks;
- Inspect drum brake linings and brake drums for wear and cracks.
CVSA offers a one-page brake inspection checklist for drivers to help guide their brake inspections.
If your company operates inspection lanes or vehicle triage lanes, get the truck through one as often as possible. Even a quick look by an expert eye could detect a defect a driver might not notice.
Here’s a bit of advice for shop personnel: procure a copy of CVSA’s North American Standard Out-of-Service Criteria handbook, and allow it to inform your brake maintenance practices. Once you understand the yardstick used by roadside inspectors, you might adjust your brake PMs from mileage-based to as-needed.
It’s not intended as a maintenance guide, as it deals with defects that can sideline a truck. The book offers important clues regarding areas that need attention. It’s available in French, as well.
And for drivers, Brake Safety Week is an educational campaign as well as an enforcement initiative. Inspectors are trained to welcome questions from drivers regarding brake defects and inspection procedures. Most of them are not mechanics, but they can offer invaluable tips on conducting your own brake inspections.
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