Maintenance,Brakes/Wheel-end Products
Even if your vehicle isn’t one of the thousands that will be selected for roadside inspections during the Commercial Vehicle Safety Alliance’s (CVSA) 2018 Brake Safety Week (Sept. 16-22), fleets and owner-operators alike should be prepared: The right pre-trip procedures and regular preventive maintenance practices not only support safe vehicle operation, but can help avoid out-of-service violations or fines during compliance checks.
Selected for Inspection? What to Expect
During Brake Safety Week, CVSA inspectors will primarily conduct the North American Standard Level I inspection, which covers a range of driver qualifications, documentation, and vehicle equipment conditions. There’s a detailed breakdown of the complete Level I process at the CVSA website, but here’s the focus in the brake system check:
- Loose or missing parts
- Air or hydraulic fluid leaks
- Worn linings, pads, drums, or rotors
- Mismatched air chamber sizes across axles
- Warning device functionality (such as antilock braking system indicator lights)
- Proper brake adjustment
When they can, inspectors will measure pushrod stroke to ensure brakes are in adjustment. Drivers can incur fines if more than 25 percent of a vehicle’s wheel-ends are noncompliant, and too many out-of-adjustment brakes can lead to an out-of-service violation. A dozen jurisdictions will also be using performance-based brake testing (PBBT) to measure vehicle braking efficiency.
Be Ready before Hitting the Road
Brake-related violations – including being out of adjustment – are consistently among the leading reasons for fines or vehicles being placed out of service during CVSA inspections. Prevention of these situations begins with proper maintenance practices in the shop and driver awareness during pre-trip checks.
Drivers should visually inspect brake components and listen for air system leaks during daily walk-arounds. It takes just a quick look at the wheel-ends to reveal damaged or loose-hanging air chambers, pushrods, or slack adjusters. It’s also pretty easy to check that slack adjusters on each axle are extended out to the same angle – if they’re different, that’s an indicator of an out-of-adjustment brake, or potentially, a broken spring brake power spring.
Getting under the vehicle once or twice a week should be sufficient for checking air disc brake rotors for cracks and inspecting the lining wear on drum brakes. And at least once a month, Bendix suggests checking the air system for moisture: Contamination can break down air system components (air seals, brake modulating valves, and brake chamber diaphragms, for instance) and cause air system leaks. Oil aerosols passed through the compressor can be particularly corrosive, so when it’s time for a replacement, Bendix advises using an oil-coalescing air dryer cartridge like the Bendix® PuraGuard®.
In the garage, maintenance teams should grease generously. Insufficient greasing can leave gaps inside the brake components, like S-cam tubes or automatic slack adjusters, where condensation can form, causing rust and corrosion. Seals inside the S-cam tube are engineered to force old, excess grease out of the end of the tube near the slack adjuster.
Also: Make sure to check friction regularly for cracks, missing pieces, or degradation, while ensuring that the proper friction is used when relining. Not all replacement friction marketed as acceptable for federal stopping distance requirements will actually perform to the standard. Replace friction like-for-like to maintain OEM performance.
All of this matters for the purposes of passing inspections, yes. But it matters for another vital reason as well. While today’s advanced commercial vehicle safety technologies are more effective and complex than ever, their safe operation still depends on the basic physics of a properly maintained braking system, supported by a team of professional technicians and regular, thorough maintenance practices.
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